** is the number of free pages currently in the database.  Meta[1]
** through meta[15] are available for use by higher layers.  Meta[0]
** is read-only, the others are read/write.
** 
** The schema layer numbers meta values differently.  At the schema
** layer (and the SetCookie and ReadCookie opcodes) the number of
** free pages is not visible.  So Cookie[0] is the same as Meta[1].







*/
void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
  BtShared *pBt = p->pBt;

  sqlite3BtreeEnter(p);
  assert( p->inTrans>TRANS_NONE );
  assert( SQLITE_OK==querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK) );
  assert( pBt->pPage1 );
  assert( idx>=0 && idx<=15 );




  *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);


  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
  ** database, mark the database as read-only.  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
    pBt->btsFlags |= BTS_READ_ONLY;
  }

** is the number of free pages currently in the database.  Meta[1]
** through meta[15] are available for use by higher layers.  Meta[0]
** is read-only, the others are read/write.
** 
** The schema layer numbers meta values differently.  At the schema
** layer (and the SetCookie and ReadCookie opcodes) the number of
** free pages is not visible.  So Cookie[0] is the same as Meta[1].
**
** This routine treats Meta[BTREE_DATA_VERSION] as a special case.  Instead
** of reading the value out of the header, it instead loads the "DataVersion"
** from the pager.  The BTREE_DATA_VERSION value is not actually stored in the
** database file.  It is a number computed by the pager.  But its access
** pattern is the same as header meta values, and so it is convenient to
** read it from this routine.
*/
void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
  BtShared *pBt = p->pBt;

  sqlite3BtreeEnter(p);
  assert( p->inTrans>TRANS_NONE );
  assert( SQLITE_OK==querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK) );
  assert( pBt->pPage1 );
  assert( idx>=0 && idx<=15 );

  if( idx==BTREE_DATA_VERSION ){
    *pMeta = sqlite3PagerDataVersion(pBt->pPager);
  }else{
    *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);
  }

  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
  ** database, mark the database as read-only.  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
    pBt->btsFlags |= BTS_READ_ONLY;
  }

*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/
#define SQLITE_N_BTREE_META 10

/*
** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
*/
#ifndef SQLITE_DEFAULT_AUTOVACUUM
  #define SQLITE_DEFAULT_AUTOVACUUM 0
................................................................................
** SQLite database header may be found using the following formula:
**
**   offset = 36 + (idx * 4)
**
** For example, the free-page-count field is located at byte offset 36 of
** the database file header. The incr-vacuum-flag field is located at
** byte offset 64 (== 36+4*7).





*/
#define BTREE_FREE_PAGE_COUNT     0
#define BTREE_SCHEMA_VERSION      1
#define BTREE_FILE_FORMAT         2
#define BTREE_DEFAULT_CACHE_SIZE  3
#define BTREE_LARGEST_ROOT_PAGE   4
#define BTREE_TEXT_ENCODING       5
#define BTREE_USER_VERSION        6
#define BTREE_INCR_VACUUM         7
#define BTREE_APPLICATION_ID      8


/*
** Values that may be OR'd together to form the second argument of an
** sqlite3BtreeCursorHints() call.
*/
#define BTREE_BULKLOAD 0x00000001

*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/
#define SQLITE_N_BTREE_META 16

/*
** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
*/
#ifndef SQLITE_DEFAULT_AUTOVACUUM
  #define SQLITE_DEFAULT_AUTOVACUUM 0
................................................................................
** SQLite database header may be found using the following formula:
**
**   offset = 36 + (idx * 4)
**
** For example, the free-page-count field is located at byte offset 36 of
** the database file header. The incr-vacuum-flag field is located at
** byte offset 64 (== 36+4*7).
**
** The BTREE_DATA_VERSION value is not really a value stored in the header.
** It is a read-only number computed by the pager.  But we merge it with
** the header value access routines since its access pattern is the same.
** Call it a "virtual meta value".
*/
#define BTREE_FREE_PAGE_COUNT     0
#define BTREE_SCHEMA_VERSION      1
#define BTREE_FILE_FORMAT         2
#define BTREE_DEFAULT_CACHE_SIZE  3
#define BTREE_LARGEST_ROOT_PAGE   4
#define BTREE_TEXT_ENCODING       5
#define BTREE_USER_VERSION        6
#define BTREE_INCR_VACUUM         7
#define BTREE_APPLICATION_ID      8
#define BTREE_DATA_VERSION        15  /* A virtual meta-value */

/*
** Values that may be OR'd together to form the second argument of an
** sqlite3BtreeCursorHints() call.
*/
#define BTREE_BULKLOAD 0x00000001

    ** incrementing a counter. This is necessary as the VM code is being
    ** generated for will not open a statement transaction.  */
    assert( nIncr==1 );
    sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
        OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
  }else{
    if( nIncr>0 && pFKey->isDeferred==0 ){
      sqlite3ParseToplevel(pParse)->mayAbort = 1;
    }
    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  }

  sqlite3VdbeResolveLabel(v, iOk);
  sqlite3VdbeAddOp1(v, OP_Close, iCur);
}
................................................................................

/*
** This function is called to generate code executed when a row is deleted
** from the parent table of foreign key constraint pFKey and, if pFKey is 
** deferred, when a row is inserted into the same table. When generating
** code for an SQL UPDATE operation, this function may be called twice -
** once to "delete" the old row and once to "insert" the new row.




**
** The code generated by this function scans through the rows in the child
** table that correspond to the parent table row being deleted or inserted.
** For each child row found, one of the following actions is taken:
**
**   Operation | FK type   | Action taken
**   --------------------------------------------------------------------------
................................................................................
  /* Resolve the references in the WHERE clause. */
  memset(&sNameContext, 0, sizeof(NameContext));
  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite3ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. If the constraint is not deferred, throw an exception for
  ** each row found. Otherwise, for deferred constraints, increment the
  ** deferred constraint counter by nIncr for each row selected.  */
  pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
  if( nIncr>0 && pFKey->isDeferred==0 ){
    sqlite3ParseToplevel(pParse)->mayAbort = 1;
  }
  sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite3WhereEnd(pWInfo);
  }

  /* Clean up the WHERE clause constructed above. */
  sqlite3ExprDelete(db, pWhere);
................................................................................
          return 1;
        }
      }
    }
  }
  return 0;
}



















/*
** This function is called when inserting, deleting or updating a row of
** table pTab to generate VDBE code to perform foreign key constraint 
** processing for the operation.
**
** For a DELETE operation, parameter regOld is passed the index of the
................................................................................
  for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
    Table *pTo;                   /* Parent table of foreign key pFKey */
    Index *pIdx = 0;              /* Index on key columns in pTo */
    int *aiFree = 0;
    int *aiCol;
    int iCol;
    int i;
    int isIgnore = 0;

    if( aChange 
     && sqlite3_stricmp(pTab->zName, pFKey->zTo)!=0
     && fkChildIsModified(pTab, pFKey, aChange, bChngRowid)==0 
    ){
      continue;
    }
................................................................................
      /* Request permission to read the parent key columns. If the 
      ** authorization callback returns SQLITE_IGNORE, behave as if any
      ** values read from the parent table are NULL. */
      if( db->xAuth ){
        int rcauth;
        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;
        rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
        isIgnore = (rcauth==SQLITE_IGNORE);
      }
#endif
    }

    /* Take a shared-cache advisory read-lock on the parent table. Allocate 
    ** a cursor to use to search the unique index on the parent key columns 
    ** in the parent table.  */
................................................................................
    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
    pParse->nTab++;

    if( regOld!=0 ){
      /* A row is being removed from the child table. Search for the parent.
      ** If the parent does not exist, removing the child row resolves an 
      ** outstanding foreign key constraint violation. */
      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1,isIgnore);
    }
    if( regNew!=0 ){
      /* A row is being added to the child table. If a parent row cannot
      ** be found, adding the child row has violated the FK constraint. */ 






      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1,isIgnore);
    }

    sqlite3DbFree(db, aiFree);
  }

  /* Loop through all the foreign key constraints that refer to this table.
  ** (the "child" constraints) */
................................................................................
      continue;
    }

    if( !pFKey->isDeferred && !(db->flags & SQLITE_DeferFKs) 
     && !pParse->pToplevel && !pParse->isMultiWrite 
    ){
      assert( regOld==0 && regNew!=0 );
      /* Inserting a single row into a parent table cannot cause an immediate
      ** foreign key violation. So do nothing in this case.  */
      continue;
    }

    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
      if( !isIgnoreErrors || db->mallocFailed ) return;
      continue;
    }
................................................................................
      pItem->pTab->nRef++;
      pItem->iCursor = pParse->nTab++;
  
      if( regNew!=0 ){
        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
      }
      if( regOld!=0 ){
        /* If there is a RESTRICT action configured for the current operation
        ** on the parent table of this FK, then throw an exception 
        ** immediately if the FK constraint is violated, even if this is a
        ** deferred trigger. That's what RESTRICT means. To defer checking
        ** the constraint, the FK should specify NO ACTION (represented
        ** using OE_None). NO ACTION is the default.  */
        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);




















      }
      pItem->zName = 0;
      sqlite3SrcListDelete(db, pSrc);
    }
    sqlite3DbFree(db, aiCol);
  }
}

    ** incrementing a counter. This is necessary as the VM code is being
    ** generated for will not open a statement transaction.  */
    assert( nIncr==1 );
    sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
        OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
  }else{
    if( nIncr>0 && pFKey->isDeferred==0 ){
      sqlite3MayAbort(pParse);
    }
    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  }

  sqlite3VdbeResolveLabel(v, iOk);
  sqlite3VdbeAddOp1(v, OP_Close, iCur);
}
................................................................................

/*
** This function is called to generate code executed when a row is deleted
** from the parent table of foreign key constraint pFKey and, if pFKey is 
** deferred, when a row is inserted into the same table. When generating
** code for an SQL UPDATE operation, this function may be called twice -
** once to "delete" the old row and once to "insert" the new row.
**
** Parameter nIncr is passed -1 when inserting a row (as this may decrease
** the number of FK violations in the db) or +1 when deleting one (as this
** may increase the number of FK constraint problems).
**
** The code generated by this function scans through the rows in the child
** table that correspond to the parent table row being deleted or inserted.
** For each child row found, one of the following actions is taken:
**
**   Operation | FK type   | Action taken
**   --------------------------------------------------------------------------
................................................................................
  /* Resolve the references in the WHERE clause. */
  memset(&sNameContext, 0, sizeof(NameContext));
  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite3ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment either the deferred or immediate
  ** foreign key constraint counter. */

  pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);



  sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite3WhereEnd(pWInfo);
  }

  /* Clean up the WHERE clause constructed above. */
  sqlite3ExprDelete(db, pWhere);
................................................................................
          return 1;
        }
      }
    }
  }
  return 0;
}

/*
** Return true if the parser passed as the first argument is being
** used to code a trigger that is really a "SET NULL" action belonging
** to trigger pFKey.
*/
static int isSetNullAction(Parse *pParse, FKey *pFKey){
  Parse *pTop = sqlite3ParseToplevel(pParse);
  if( pTop->pTriggerPrg ){
    Trigger *p = pTop->pTriggerPrg->pTrigger;
    if( (p==pFKey->apTrigger[0] && pFKey->aAction[0]==OE_SetNull)
     || (p==pFKey->apTrigger[1] && pFKey->aAction[1]==OE_SetNull)
    ){
      return 1;
    }
  }
  return 0;
}

/*
** This function is called when inserting, deleting or updating a row of
** table pTab to generate VDBE code to perform foreign key constraint 
** processing for the operation.
**
** For a DELETE operation, parameter regOld is passed the index of the
................................................................................
  for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
    Table *pTo;                   /* Parent table of foreign key pFKey */
    Index *pIdx = 0;              /* Index on key columns in pTo */
    int *aiFree = 0;
    int *aiCol;
    int iCol;
    int i;
    int bIgnore = 0;

    if( aChange 
     && sqlite3_stricmp(pTab->zName, pFKey->zTo)!=0
     && fkChildIsModified(pTab, pFKey, aChange, bChngRowid)==0 
    ){
      continue;
    }
................................................................................
      /* Request permission to read the parent key columns. If the 
      ** authorization callback returns SQLITE_IGNORE, behave as if any
      ** values read from the parent table are NULL. */
      if( db->xAuth ){
        int rcauth;
        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;
        rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
        bIgnore = (rcauth==SQLITE_IGNORE);
      }
#endif
    }

    /* Take a shared-cache advisory read-lock on the parent table. Allocate 
    ** a cursor to use to search the unique index on the parent key columns 
    ** in the parent table.  */
................................................................................
    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
    pParse->nTab++;

    if( regOld!=0 ){
      /* A row is being removed from the child table. Search for the parent.
      ** If the parent does not exist, removing the child row resolves an 
      ** outstanding foreign key constraint violation. */
      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1, bIgnore);
    }
    if( regNew!=0 && !isSetNullAction(pParse, pFKey) ){
      /* A row is being added to the child table. If a parent row cannot
      ** be found, adding the child row has violated the FK constraint. 
      **
      ** If this operation is being performed as part of a trigger program
      ** that is actually a "SET NULL" action belonging to this very 
      ** foreign key, then omit this scan altogether. As all child key
      ** values are guaranteed to be NULL, it is not possible for adding
      ** this row to cause an FK violation.  */
      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1, bIgnore);
    }

    sqlite3DbFree(db, aiFree);
  }

  /* Loop through all the foreign key constraints that refer to this table.
  ** (the "child" constraints) */
................................................................................
      continue;
    }

    if( !pFKey->isDeferred && !(db->flags & SQLITE_DeferFKs) 
     && !pParse->pToplevel && !pParse->isMultiWrite 
    ){
      assert( regOld==0 && regNew!=0 );
      /* Inserting a single row into a parent table cannot cause (or fix)
      ** an immediate foreign key violation. So do nothing in this case.  */
      continue;
    }

    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
      if( !isIgnoreErrors || db->mallocFailed ) return;
      continue;
    }
................................................................................
      pItem->pTab->nRef++;
      pItem->iCursor = pParse->nTab++;
  
      if( regNew!=0 ){
        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
      }
      if( regOld!=0 ){
        int eAction = pFKey->aAction[aChange!=0];





        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);
        /* If this is a deferred FK constraint, or a CASCADE or SET NULL
        ** action applies, then any foreign key violations caused by
        ** removing the parent key will be rectified by the action trigger.
        ** So do not set the "may-abort" flag in this case.
        **
        ** Note 1: If the FK is declared "ON UPDATE CASCADE", then the
        ** may-abort flag will eventually be set on this statement anyway
        ** (when this function is called as part of processing the UPDATE
        ** within the action trigger).
        **
        ** Note 2: At first glance it may seem like SQLite could simply omit
        ** all OP_FkCounter related scans when either CASCADE or SET NULL
        ** applies. The trouble starts if the CASCADE or SET NULL action 
        ** trigger causes other triggers or action rules attached to the 
        ** child table to fire. In these cases the fk constraint counters
        ** might be set incorrectly if any OP_FkCounter related scans are 
        ** omitted.  */
        if( !pFKey->isDeferred && eAction!=OE_Cascade && eAction!=OE_SetNull ){
          sqlite3MayAbort(pParse);
        }
      }
      pItem->zName = 0;
      sqlite3SrcListDelete(db, pSrc);
    }
    sqlite3DbFree(db, aiCol);
  }
}

  */
  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
  u8 eLock;                   /* Current lock held on database file */
  u8 changeCountDone;         /* Set after incrementing the change-counter */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
  u8 doNotSpill;              /* Do not spill the cache when non-zero */
  u8 subjInMemory;            /* True to use in-memory sub-journals */

  Pgno dbSize;                /* Number of pages in the database */
  Pgno dbOrigSize;            /* dbSize before the current transaction */
  Pgno dbFileSize;            /* Number of pages in the database file */
  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
  int errCode;                /* One of several kinds of errors */
  int nRec;                   /* Pages journalled since last j-header written */
  u32 cksumInit;              /* Quasi-random value added to every checksum */
................................................................................
  sqlite3_file *jfd;          /* File descriptor for main journal */
  sqlite3_file *sjfd;         /* File descriptor for sub-journal */
  i64 journalOff;             /* Current write offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */
  sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
  PagerSavepoint *aSavepoint; /* Array of active savepoints */
  int nSavepoint;             /* Number of elements in aSavepoint[] */

  char dbFileVers[16];        /* Changes whenever database file changes */

  u8 bUseFetch;               /* True to use xFetch() */
  int nMmapOut;               /* Number of mmap pages currently outstanding */
  sqlite3_int64 szMmap;       /* Desired maximum mmap size */
  PgHdr *pMmapFreelist;       /* List of free mmap page headers (pDirty) */
  /*
  ** End of the routinely-changing class members
  ***************************************************************************/

................................................................................
  return rc;
}

/*
** Discard the entire contents of the in-memory page-cache.
*/
static void pager_reset(Pager *pPager){

  sqlite3BackupRestart(pPager->pBackup);
  sqlite3PcacheClear(pPager->pPCache);
}









/*
** Free all structures in the Pager.aSavepoint[] array and set both
** Pager.aSavepoint and Pager.nSavepoint to zero. Close the sub-journal
** if it is open and the pager is not in exclusive mode.
*/
static void releaseAllSavepoints(Pager *pPager){
................................................................................
  ){
    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
    pPager->eState = PAGER_READER;
    return SQLITE_OK;
  }

  PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));

  rc = pager_end_transaction(pPager, pPager->setMaster, 1);
  return pager_error(pPager, rc);
}

/*
** If a write transaction is open, then all changes made within the 
** transaction are reverted and the current write-transaction is closed.

  */
  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
  u8 eLock;                   /* Current lock held on database file */
  u8 changeCountDone;         /* Set after incrementing the change-counter */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
  u8 doNotSpill;              /* Do not spill the cache when non-zero */
  u8 subjInMemory;            /* True to use in-memory sub-journals */
  u8 bUseFetch;               /* True to use xFetch() */
  Pgno dbSize;                /* Number of pages in the database */
  Pgno dbOrigSize;            /* dbSize before the current transaction */
  Pgno dbFileSize;            /* Number of pages in the database file */
  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
  int errCode;                /* One of several kinds of errors */
  int nRec;                   /* Pages journalled since last j-header written */
  u32 cksumInit;              /* Quasi-random value added to every checksum */
................................................................................
  sqlite3_file *jfd;          /* File descriptor for main journal */
  sqlite3_file *sjfd;         /* File descriptor for sub-journal */
  i64 journalOff;             /* Current write offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */
  sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
  PagerSavepoint *aSavepoint; /* Array of active savepoints */
  int nSavepoint;             /* Number of elements in aSavepoint[] */
  u32 iDataVersion;           /* Changes whenever database content changes */
  char dbFileVers[16];        /* Changes whenever database file changes */


  int nMmapOut;               /* Number of mmap pages currently outstanding */
  sqlite3_int64 szMmap;       /* Desired maximum mmap size */
  PgHdr *pMmapFreelist;       /* List of free mmap page headers (pDirty) */
  /*
  ** End of the routinely-changing class members
  ***************************************************************************/

................................................................................
  return rc;
}

/*
** Discard the entire contents of the in-memory page-cache.
*/
static void pager_reset(Pager *pPager){
  pPager->iDataVersion++;
  sqlite3BackupRestart(pPager->pBackup);
  sqlite3PcacheClear(pPager->pPCache);
}

/*
** Return the pPager->iDataVersion value
*/
u32 sqlite3PagerDataVersion(Pager *pPager){
  assert( pPager->eState>PAGER_OPEN );
  return pPager->iDataVersion;
}

/*
** Free all structures in the Pager.aSavepoint[] array and set both
** Pager.aSavepoint and Pager.nSavepoint to zero. Close the sub-journal
** if it is open and the pager is not in exclusive mode.
*/
static void releaseAllSavepoints(Pager *pPager){
................................................................................
  ){
    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
    pPager->eState = PAGER_READER;
    return SQLITE_OK;
  }

  PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
  pPager->iDataVersion++;
  rc = pager_end_transaction(pPager, pPager->setMaster, 1);
  return pager_error(pPager, rc);
}

/*
** If a write transaction is open, then all changes made within the 
** transaction are reverted and the current write-transaction is closed.

#ifdef SQLITE_ENABLE_ZIPVFS
  int sqlite3PagerWalFramesize(Pager *pPager);
#endif

/* Functions used to query pager state and configuration. */
u8 sqlite3PagerIsreadonly(Pager*);

int sqlite3PagerRefcount(Pager*);
int sqlite3PagerMemUsed(Pager*);
const char *sqlite3PagerFilename(Pager*, int);
const sqlite3_vfs *sqlite3PagerVfs(Pager*);
sqlite3_file *sqlite3PagerFile(Pager*);
const char *sqlite3PagerJournalname(Pager*);
int sqlite3PagerNosync(Pager*);

#ifdef SQLITE_ENABLE_ZIPVFS
  int sqlite3PagerWalFramesize(Pager *pPager);
#endif

/* Functions used to query pager state and configuration. */
u8 sqlite3PagerIsreadonly(Pager*);
u32 sqlite3PagerDataVersion(Pager*);
int sqlite3PagerRefcount(Pager*);
int sqlite3PagerMemUsed(Pager*);
const char *sqlite3PagerFilename(Pager*, int);
const sqlite3_vfs *sqlite3PagerVfs(Pager*);
sqlite3_file *sqlite3PagerFile(Pager*);
const char *sqlite3PagerJournalname(Pager*);
int sqlite3PagerNosync(Pager*);

#define PragTyp_ACTIVATE_EXTENSIONS           36
#define PragTyp_HEXKEY                        37
#define PragTyp_KEY                           38
#define PragTyp_REKEY                         39
#define PragTyp_LOCK_STATUS                   40
#define PragTyp_PARSER_TRACE                  41
#define PragFlag_NeedSchema           0x01

static const struct sPragmaNames {
  const char *const zName;  /* Name of pragma */
  u8 ePragTyp;              /* PragTyp_XXX value */
  u8 mPragFlag;             /* Zero or more PragFlag_XXX values */
  u32 iArg;                 /* Extra argument */
} aPragmaNames[] = {
#if defined(SQLITE_HAS_CODEC) || defined(SQLITE_ENABLE_CEROD)
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "application_id",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_AUTOVACUUM)
  { /* zName:     */ "auto_vacuum",
    /* ePragTyp:  */ PragTyp_AUTO_VACUUM,
    /* ePragFlag: */ PragFlag_NeedSchema,
    /* iArg:      */ 0 },
#endif
................................................................................
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_OS_WIN
  { /* zName:     */ "data_store_directory",
    /* ePragTyp:  */ PragTyp_DATA_STORE_DIRECTORY,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif






#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
  { /* zName:     */ "database_list",
    /* ePragTyp:  */ PragTyp_DATABASE_LIST,
    /* ePragFlag: */ PragFlag_NeedSchema,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_ForeignKeys },
#endif
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "freelist_count",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
  { /* zName:     */ "full_column_names",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_FullColNames },
  { /* zName:     */ "fullfsync",
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_ReverseOrder },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "schema_version",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
  { /* zName:     */ "secure_delete",
    /* ePragTyp:  */ PragTyp_SECURE_DELETE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
................................................................................
    /* ePragTyp:  */ PragTyp_THREADS,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "user_version",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
#if defined(SQLITE_DEBUG)
  { /* zName:     */ "vdbe_addoptrace",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_VdbeAddopTrace },
................................................................................
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
  { /* zName:     */ "writable_schema",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_WriteSchema|SQLITE_RecoveryMode },
#endif
};
/* Number of pragmas: 57 on by default, 70 total. */
/* End of the automatically generated pragma table.
***************************************************************************/

/*
** Interpret the given string as a safety level.  Return 0 for OFF,
** 1 for ON or NORMAL and 2 for FULL.  Return 1 for an empty or 
** unrecognized string argument.  The FULL option is disallowed
................................................................................
  ** the schema-version is potentially dangerous and may lead to program
  ** crashes or database corruption. Use with caution!
  **
  ** The user-version is not used internally by SQLite. It may be used by
  ** applications for any purpose.
  */
  case PragTyp_HEADER_VALUE: {
    int iCookie;   /* Cookie index. 1 for schema-cookie, 6 for user-cookie. */
    sqlite3VdbeUsesBtree(v, iDb);
    switch( zLeft[0] ){
      case 'a': case 'A':
        iCookie = BTREE_APPLICATION_ID;
        break;
      case 'f': case 'F':
        iCookie = BTREE_FREE_PAGE_COUNT;
        break;
      case 's': case 'S':
        iCookie = BTREE_SCHEMA_VERSION;
        break;
      default:
        iCookie = BTREE_USER_VERSION;
        break;
    }

    if( zRight && iCookie!=BTREE_FREE_PAGE_COUNT ){
      /* Write the specified cookie value */
      static const VdbeOpList setCookie[] = {
        { OP_Transaction,    0,  1,  0},    /* 0 */
        { OP_Integer,        0,  1,  0},    /* 1 */
        { OP_SetCookie,      0,  0,  1},    /* 2 */
      };
      int addr = sqlite3VdbeAddOpList(v, ArraySize(setCookie), setCookie, 0);

#define PragTyp_ACTIVATE_EXTENSIONS           36
#define PragTyp_HEXKEY                        37
#define PragTyp_KEY                           38
#define PragTyp_REKEY                         39
#define PragTyp_LOCK_STATUS                   40
#define PragTyp_PARSER_TRACE                  41
#define PragFlag_NeedSchema           0x01
#define PragFlag_ReadOnly             0x02
static const struct sPragmaNames {
  const char *const zName;  /* Name of pragma */
  u8 ePragTyp;              /* PragTyp_XXX value */
  u8 mPragFlag;             /* Zero or more PragFlag_XXX values */
  u32 iArg;                 /* Extra argument */
} aPragmaNames[] = {
#if defined(SQLITE_HAS_CODEC) || defined(SQLITE_ENABLE_CEROD)
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "application_id",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ BTREE_APPLICATION_ID },
#endif
#if !defined(SQLITE_OMIT_AUTOVACUUM)
  { /* zName:     */ "auto_vacuum",
    /* ePragTyp:  */ PragTyp_AUTO_VACUUM,
    /* ePragFlag: */ PragFlag_NeedSchema,
    /* iArg:      */ 0 },
#endif
................................................................................
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_OS_WIN
  { /* zName:     */ "data_store_directory",
    /* ePragTyp:  */ PragTyp_DATA_STORE_DIRECTORY,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "data_version",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ PragFlag_ReadOnly,
    /* iArg:      */ BTREE_DATA_VERSION },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
  { /* zName:     */ "database_list",
    /* ePragTyp:  */ PragTyp_DATABASE_LIST,
    /* ePragFlag: */ PragFlag_NeedSchema,
    /* iArg:      */ 0 },
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_ForeignKeys },
#endif
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "freelist_count",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ PragFlag_ReadOnly,
    /* iArg:      */ BTREE_FREE_PAGE_COUNT },
#endif
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
  { /* zName:     */ "full_column_names",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_FullColNames },
  { /* zName:     */ "fullfsync",
................................................................................
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_ReverseOrder },
#endif
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "schema_version",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ BTREE_SCHEMA_VERSION },
#endif
#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
  { /* zName:     */ "secure_delete",
    /* ePragTyp:  */ PragTyp_SECURE_DELETE,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#endif
................................................................................
    /* ePragTyp:  */ PragTyp_THREADS,
    /* ePragFlag: */ 0,
    /* iArg:      */ 0 },
#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
  { /* zName:     */ "user_version",
    /* ePragTyp:  */ PragTyp_HEADER_VALUE,
    /* ePragFlag: */ 0,
    /* iArg:      */ BTREE_USER_VERSION },
#endif
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
#if defined(SQLITE_DEBUG)
  { /* zName:     */ "vdbe_addoptrace",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_VdbeAddopTrace },
................................................................................
#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
  { /* zName:     */ "writable_schema",
    /* ePragTyp:  */ PragTyp_FLAG,
    /* ePragFlag: */ 0,
    /* iArg:      */ SQLITE_WriteSchema|SQLITE_RecoveryMode },
#endif
};
/* Number of pragmas: 58 on by default, 71 total. */
/* End of the automatically generated pragma table.
***************************************************************************/

/*
** Interpret the given string as a safety level.  Return 0 for OFF,
** 1 for ON or NORMAL and 2 for FULL.  Return 1 for an empty or 
** unrecognized string argument.  The FULL option is disallowed
................................................................................
  ** the schema-version is potentially dangerous and may lead to program
  ** crashes or database corruption. Use with caution!
  **
  ** The user-version is not used internally by SQLite. It may be used by
  ** applications for any purpose.
  */
  case PragTyp_HEADER_VALUE: {
    int iCookie = aPragmaNames[mid].iArg;  /* Which cookie to read or write */
    sqlite3VdbeUsesBtree(v, iDb);
    if( zRight && (aPragmaNames[mid].mPragFlag & PragFlag_ReadOnly)==0 ){















      /* Write the specified cookie value */
      static const VdbeOpList setCookie[] = {
        { OP_Transaction,    0,  1,  0},    /* 0 */
        { OP_Integer,        0,  1,  0},    /* 1 */
        { OP_SetCookie,      0,  0,  1},    /* 2 */
      };
      int addr = sqlite3VdbeAddOpList(v, ArraySize(setCookie), setCookie, 0);

** match, or false otherwise. This function is intended to be used as
** part of an assert statement in the compiler. Similar to:
**
**   assert( sqlite3VdbeAssertMayAbort(pParse->pVdbe, pParse->mayAbort) );
*/
int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
  int hasAbort = 0;

  Op *pOp;
  VdbeOpIter sIter;
  memset(&sIter, 0, sizeof(sIter));
  sIter.v = v;

  while( (pOp = opIterNext(&sIter))!=0 ){
    int opcode = pOp->opcode;
    if( opcode==OP_Destroy || opcode==OP_VUpdate || opcode==OP_VRename 
#ifndef SQLITE_OMIT_FOREIGN_KEY
     || (opcode==OP_FkCounter && pOp->p1==0 && pOp->p2==1) 
#endif
     || ((opcode==OP_Halt || opcode==OP_HaltIfNull) 
      && ((pOp->p1&0xff)==SQLITE_CONSTRAINT && pOp->p2==OE_Abort))
    ){
      hasAbort = 1;
      break;
    }





  }
  sqlite3DbFree(v->db, sIter.apSub);

  /* Return true if hasAbort==mayAbort. Or if a malloc failure occurred.
  ** If malloc failed, then the while() loop above may not have iterated
  ** through all opcodes and hasAbort may be set incorrectly. Return
  ** true for this case to prevent the assert() in the callers frame
  ** from failing.  */
  return ( v->db->mallocFailed || hasAbort==mayAbort );
}
#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */

/*
** Loop through the program looking for P2 values that are negative
** on jump instructions.  Each such value is a label.  Resolve the
** label by setting the P2 value to its correct non-zero value.

** match, or false otherwise. This function is intended to be used as
** part of an assert statement in the compiler. Similar to:
**
**   assert( sqlite3VdbeAssertMayAbort(pParse->pVdbe, pParse->mayAbort) );
*/
int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
  int hasAbort = 0;
  int hasFkCounter = 0;
  Op *pOp;
  VdbeOpIter sIter;
  memset(&sIter, 0, sizeof(sIter));
  sIter.v = v;

  while( (pOp = opIterNext(&sIter))!=0 ){
    int opcode = pOp->opcode;
    if( opcode==OP_Destroy || opcode==OP_VUpdate || opcode==OP_VRename 



     || ((opcode==OP_Halt || opcode==OP_HaltIfNull) 
      && ((pOp->p1&0xff)==SQLITE_CONSTRAINT && pOp->p2==OE_Abort))
    ){
      hasAbort = 1;
      break;
    }
#ifndef SQLITE_OMIT_FOREIGN_KEY
    if( opcode==OP_FkCounter && pOp->p1==0 && pOp->p2==1 ){
      hasFkCounter = 1;
    }
#endif
  }
  sqlite3DbFree(v->db, sIter.apSub);

  /* Return true if hasAbort==mayAbort. Or if a malloc failure occurred.
  ** If malloc failed, then the while() loop above may not have iterated
  ** through all opcodes and hasAbort may be set incorrectly. Return
  ** true for this case to prevent the assert() in the callers frame
  ** from failing.  */
  return ( v->db->mallocFailed || hasAbort==mayAbort || hasFkCounter );
}
#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */

/*
** Loop through the program looking for P2 values that are negative
** on jump instructions.  Each such value is a label.  Resolve the
** label by setting the P2 value to its correct non-zero value.

} {

  eval $code

  reset_db
  do_execsql_test 1.$tn.0 { PRAGMA journal_mode = WAL } {wal}
  do_execsql_test 1.$tn.1 { CREATE TABLE t1(a, b) }
  set shmfd [open "test.db-shm"]

  # EVIDENCE-OF: R-41531-51083 Every new database connection defaults to
  # having the auto-checkpoint enabled with a threshold of 1000 or
  # SQLITE_DEFAULT_WAL_AUTOCHECKPOINT pages.
  #
  do_autocommit_threshold_test 1.$tn.2 1000
  db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }

} {

  eval $code

  reset_db
  do_execsql_test 1.$tn.0 { PRAGMA journal_mode = WAL } {wal}
  do_execsql_test 1.$tn.1 { CREATE TABLE t1(a, b) }
  set shmfd [open "test.db-shm" rb]

  # EVIDENCE-OF: R-41531-51083 Every new database connection defaults to
  # having the auto-checkpoint enabled with a threshold of 1000 or
  # SQLITE_DEFAULT_WAL_AUTOCHECKPOINT pages.
  #
  do_autocommit_threshold_test 1.$tn.2 1000
  db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for foreign keys.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix fkey8

ifcapable {!foreignkey} {
  finish_test
  return
}
do_execsql_test 1.0 { PRAGMA foreign_keys = 1; }


foreach {tn use_stmt sql schema} {
  1   1 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1);
  }

  2.1     0 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE CASCADE);
  }
  2.2   0 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE SET NULL);
  }
  2.3   1 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE SET DEFAULT);
  }

  3   1 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE CASCADE);
    CREATE TRIGGER ct1 AFTER DELETE ON c1 BEGIN
      INSERT INTO p1 VALUES('x');
    END;
  }

  4   1 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE CASCADE, c PRIMARY KEY);
    CREATE TABLE cc1(d REFERENCES c1);
  }

  5.1   0 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE CASCADE, c PRIMARY KEY);
    CREATE TABLE cc1(d REFERENCES c1 ON DELETE CASCADE);
  }
  5.2   0 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE CASCADE, c PRIMARY KEY);
    CREATE TABLE cc1(d REFERENCES c1 ON DELETE SET NULL);
  }
  5.3   1 "DELETE FROM p1" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON DELETE CASCADE, c PRIMARY KEY);
    CREATE TABLE cc1(d REFERENCES c1 ON DELETE SET DEFAULT);
  }

  6.1   1 "UPDATE p1 SET a = ?" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON UPDATE SET NULL, c);
  }
  6.2   0 "UPDATE OR IGNORE p1 SET a = ?" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON UPDATE SET NULL, c);
  }
  6.3   1 "UPDATE OR IGNORE p1 SET a = ?" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b REFERENCES p1 ON UPDATE CASCADE, c);
  }
  6.4   1 "UPDATE OR IGNORE p1 SET a = ?" {
    CREATE TABLE p1(a PRIMARY KEY);
    CREATE TABLE c1(b NOT NULL REFERENCES p1 ON UPDATE SET NULL, c);
  }

} {
  drop_all_tables
  do_test 1.$tn {
    execsql $schema
    set stmt [sqlite3_prepare_v2 db $sql -1 dummy]
    set ret [uses_stmt_journal $stmt]
    sqlite3_finalize $stmt
    set ret
  } $use_stmt
}


finish_test

# 2014-12-19
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for PRAGMA data_version command.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

do_execsql_test pragma3-100 {
  PRAGMA data_version;
} {1}
do_execsql_test pragma3-101 {
  PRAGMA temp.data_version;
} {1}

# Writing to the pragma is a no-op 
do_execsql_test pragma3-102 {
  PRAGMA main.data_version=1234;
  PRAGMA main.data_version;
} {1 1}

# EVIDENCE-OF: R-27726-60934 The "PRAGMA data_version" command provides
# an indication that the database file has been modified.
#
# EVIDENCE-OF: R-30058-27547 The integer values returned by two
# invocations of "PRAGMA data_version" will be different if changes
# where committed to that database in between the two invocations.
#
# EVIDENCE-OF: R-10201-09349 The "PRAGMA data_version" command responses
# to changes committed by the same database connection, by database
# connections sharing a cache in shared cache mode, and by completely
# independent database connections including connections in separate
# threads and processes.
#
# In this test, it response to two separate changes on the same database
# connection.
#
do_execsql_test pragma3-110 {
  CREATE TABLE t1(a);
  INSERT INTO t1 VALUES(100),(200),(300);
  SELECT * FROM t1;
  PRAGMA data_version;
} {100 200 300 3}

sqlite3 db2 test.db
do_test pragma3-120 {
  db2 eval {
    SELECT * FROM t1;
    PRAGMA data_version;
  }
} {100 200 300 1}

do_execsql_test pragma3-130 {
  INSERT INTO t1 VALUES(400),(500);
  SELECT * FROM t1;
  PRAGMA data_version;
} {100 200 300 400 500 4}

# EVIDENCE-OF: R-10201-09349 The "PRAGMA data_version" command responses
# to changes committed by the same database connection, by database
# connections sharing a cache in shared cache mode, and by completely
# independent database connections including connections in separate
# threads and processes.
#
# In these test, it response to changes in a different database connection
# part of the same process.
#
do_test pragma3-140 {
  db2 eval {
    SELECT * FROM t1;
    PRAGMA data_version;
    UPDATE t1 SET a=a+1;
    SELECT * FROM t1;
    PRAGMA data_version;
  }
} {100 200 300 400 500 2 101 201 301 401 501 3}
do_execsql_test pragma3-150 {
  SELECT * FROM t1;
  PRAGMA data_version;
} {101 201 301 401 501 5}

# EVIDENCE-OF: R-10201-09349 The "PRAGMA data_version" command responses
# to changes committed by the same database connection, by database
# connections sharing a cache in shared cache mode, and by completely
# independent database connections including connections in separate
# threads and processes.
#
# This test verifies behavior when a separate process changes the database
# file.
#
do_test pragma3-200 {
  set fd [open pragma3.txt wb]
  puts $fd {
     sqlite3 db test.db;
     db eval {DELETE FROM t1 WHERE a>300};
     db close;
     exit;
  }
  close $fd
  exec [info nameofexec] pragma3.txt
  forcedelete pragma3.txt
  db eval {
    PRAGMA data_version;
    SELECT * FROM t1;
  }
} {6 101 201}
db2 close
db close

# EVIDENCE-OF: R-10201-09349 The "PRAGMA data_version" command responses
# to changes committed by the same database connection, by database
# connections sharing a cache in shared cache mode, and by completely
# independent database connections including connections in separate
# threads and processes.
#
# The next series of tests verifies the behavior for shared-cache
# database connections.
#
ifcapable shared_cache {
  set ::enable_shared_cache [sqlite3_enable_shared_cache 1]
  sqlite3 db test.db
  sqlite3 db2 test.db
  do_test pragma3-300 {
    db eval {
      PRAGMA data_version;
      CREATE TABLE t3(a,b,c);
      PRAGMA data_version;
    }
  } {1 2}
  do_test pragma3-310 {
    db2 eval {
      PRAGMA data_version;
      INSERT INTO t3(a,b,c) VALUES('abc','def','ghi');
      SELECT * FROM t3;
      PRAGMA data_version;
    }
  } {2 abc def ghi 3}
  do_test pragma3-320 {
    db eval {
      PRAGMA data_version;
      SELECT * FROM t3;
    }
  } {3 abc def ghi}
  db2 close
  db close
  sqlite3_enable_shared_cache $::enable_shared_cache
}

# Make sure this also works in WAL mode
#
ifcapable wal {
  sqlite3 db test.db
  db eval {PRAGMA journal_mode=WAL}
  sqlite3 db2 test.db
  do_test pragma3-400 {
    db eval {
      PRAGMA data_version;
      PRAGMA journal_mode;
      SELECT * FROM t1;
    }
  } {3 wal 101 201}
  do_test pragma3-410 {
    db2 eval {
      PRAGMA data_version;
      PRAGMA journal_mode;
      SELECT * FROM t1;
    }
  } {2 wal 101 201}
  do_test pragma3-420 {
    db eval {UPDATE t1 SET a=111*(a/100); PRAGMA data_version; SELECT * FROM t1}
  } {4 111 222}
  do_test pragma3-430 {
    db2 eval {PRAGMA data_version; SELECT * FROM t1;}
  } {3 111 222}
  db2 close
}

finish_test

  IF:   !defined(SQLITE_OMIT_INTEGRITY_CHECK)

  NAME: encoding
  IF:   !defined(SQLITE_OMIT_UTF16)

  NAME: schema_version
  TYPE: HEADER_VALUE

  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: user_version
  TYPE: HEADER_VALUE







  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: freelist_count
  TYPE: HEADER_VALUE


  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: application_id
  TYPE: HEADER_VALUE

  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: compile_options
  IF:   !defined(SQLITE_OMIT_COMPILEOPTION_DIAGS)

  NAME: wal_checkpoint
  FLAG: NeedSchema

  IF:   !defined(SQLITE_OMIT_INTEGRITY_CHECK)

  NAME: encoding
  IF:   !defined(SQLITE_OMIT_UTF16)

  NAME: schema_version
  TYPE: HEADER_VALUE
  ARG:  BTREE_SCHEMA_VERSION
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: user_version
  TYPE: HEADER_VALUE
  ARG:  BTREE_USER_VERSION
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: data_version
  TYPE: HEADER_VALUE
  ARG:  BTREE_DATA_VERSION
  FLAG: ReadOnly
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: freelist_count
  TYPE: HEADER_VALUE
  ARG:  BTREE_FREE_PAGE_COUNT
  FLAG: ReadOnly
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: application_id
  TYPE: HEADER_VALUE
  ARG:  BTREE_APPLICATION_ID
  IF:   !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)

  NAME: compile_options
  IF:   !defined(SQLITE_OMIT_COMPILEOPTION_DIAGS)

  NAME: wal_checkpoint
  FLAG: NeedSchema