/* Drop the table and index from the internal schema.  */
  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);

  /* Reload the table, index and permanent trigger schemas. */
  zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
  if( !zWhere ) return;
  sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);

#ifndef SQLITE_OMIT_TRIGGER
  /* Now, if the table is not stored in the temp database, reload any temp 
  ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. 
  */
  if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
    sqlite3VdbeAddParseSchemaOp(v, 1, zWhere);
  }
#endif
}

/*
** Parameter zName is the name of a table that is about to be altered
** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).

  /* Drop the table and index from the internal schema.  */
  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);

  /* Reload the table, index and permanent trigger schemas. */
  zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
  if( !zWhere ) return;
  sqlite3VdbeAddParseSchemaOp(pParse, iDb, zWhere);

#ifndef SQLITE_OMIT_TRIGGER
  /* Now, if the table is not stored in the temp database, reload any temp 
  ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined. 
  */
  if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
    sqlite3VdbeAddParseSchemaOp(pParse, 1, zWhere);
  }
#endif
}

/*
** Parameter zName is the name of a table that is about to be altered
** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).

  sqlite3 *db = pParse->db;
  Schema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
  HashElem *k;
  int iStatCur;
  int iMem;
  int iTab;


  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab;
  pParse->nTab += 3;
  openStatTable(pParse, iDb, iStatCur, 0, 0);
  iMem = pParse->nMem+1;
  iTab = pParse->nTab;
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );

  sqlite3 *db = pParse->db;
  Schema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
  HashElem *k;
  int iStatCur;
  int iMem;
  int iTab;

  sqlite3SchemaWritable(pParse, iDb);
  sqlite3BeginWriteOperation(pParse, 0, iDb);
  iStatCur = pParse->nTab;
  pParse->nTab += 3;
  openStatTable(pParse, iDb, iStatCur, 0, 0);
  iMem = pParse->nMem+1;
  iTab = pParse->nTab;
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );

}

/*
** Reset the schema for the database at index iDb.  Also reset the
** TEMP schema.
*/
void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
  Db *pDb;
  assert( iDb<db->nDb );

  /* Case 1:  Reset the single schema identified by iDb */

  pDb = &db->aDb[iDb];
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
  assert( pDb->pSchema!=0 );
  sqlite3SchemaClear(pDb->pSchema);

  /* If any database other than TEMP is reset, then also reset TEMP
  ** since TEMP might be holding triggers that reference tables in the
  ** other database.
  */

  if( iDb!=1 ){
    pDb = &db->aDb[1];
    assert( pDb->pSchema!=0 );
    sqlite3SchemaClear(pDb->pSchema);
  }
  return;
}

/*
** Erase all schema information from all attached databases (including
** "main" and "temp") for a single database connection.
*/
void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
  int i;
  sqlite3BtreeEnterAll(db);
  for(i=0; i<db->nDb; i++){
    Db *pDb = &db->aDb[i];
    if( pDb->pSchema ){
      sqlite3SchemaClear(pDb->pSchema);
    }

  }
  db->mDbFlags &= ~DBFLAG_SchemaChange;
  sqlite3VtabUnlockList(db);
  sqlite3BtreeLeaveAll(db);
  sqlite3CollapseDatabaseArray(db);
}

/*
................................................................................
          pDb->zDbSName
        );
      }
    }
#endif

    /* Reparse everything to update our internal data structures */
    sqlite3VdbeAddParseSchemaOp(v, iDb,
           sqlite3MPrintf(db, "tbl_name='%q' AND type!='trigger'", p->zName));
  }


  /* Add the table to the in-memory representation of the database.
  */
  if( db->init.busy ){
................................................................................

  if( pTab==0 ){
    if( noErr ) sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
    goto exit_drop_table;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb>=0 && iDb<db->nDb );


  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
  ** it is initialized.
  */
  if( IsVirtual(pTab) && sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto exit_drop_table;
  }
................................................................................

    /* Fill the index with data and reparse the schema. Code an OP_Expire
    ** to invalidate all pre-compiled statements.
    */
    if( pTblName ){
      sqlite3RefillIndex(pParse, pIndex, iMem);
      sqlite3ChangeCookie(pParse, iDb);
      sqlite3VdbeAddParseSchemaOp(v, iDb,
         sqlite3MPrintf(db, "name='%q' AND type='index'", pIndex->zName));
      sqlite3VdbeAddOp0(v, OP_Expire);
    }

    sqlite3VdbeJumpHere(v, pIndex->tnum);
  }

................................................................................
  }
  if( pIndex->idxType!=SQLITE_IDXTYPE_APPDEF ){
    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
      "or PRIMARY KEY constraint cannot be dropped", 0);
    goto exit_drop_index;
  }
  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_INDEX;
    Table *pTab = pIndex->pTable;
    const char *zDb = db->aDb[iDb].zDbSName;
    const char *zTab = SCHEMA_TABLE(iDb);
    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){

}

/*
** Reset the schema for the database at index iDb.  Also reset the
** TEMP schema.
*/
void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
  /* If any database other than TEMP is reset, then also reset TEMP
  ** since TEMP might be holding triggers that reference tables in the


  ** other database.  */
  Db *pDb = &db->aDb[1];

  assert( pDb->pSchema!=0 );
  sqlite3SchemaClear(pDb->pSchema);

  assert( iDb<db->nDb );
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
  assert( db->aDb[iDb].pSchema!=0 );


  if( iDb!=1 ){


    sqlite3SchemaUnuse(db, iDb);
  }
  return;
}

/*
** Erase all schema information from all attached databases (including
** "main" and "temp") for a single database connection.
*/
void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
  int i;
  sqlite3BtreeEnterAll(db);
  for(i=0; i<db->nDb; i = (i?i+1:2)){


    sqlite3SchemaUnuse(db, i);
  }
  sqlite3SchemaClear(db->aDb[1].pSchema);

  db->mDbFlags &= ~DBFLAG_SchemaChange;
  sqlite3VtabUnlockList(db);
  sqlite3BtreeLeaveAll(db);
  sqlite3CollapseDatabaseArray(db);
}

/*
................................................................................
          pDb->zDbSName
        );
      }
    }
#endif

    /* Reparse everything to update our internal data structures */
    sqlite3VdbeAddParseSchemaOp(pParse, iDb,
           sqlite3MPrintf(db, "tbl_name='%q' AND type!='trigger'", p->zName));
  }


  /* Add the table to the in-memory representation of the database.
  */
  if( db->init.busy ){
................................................................................

  if( pTab==0 ){
    if( noErr ) sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
    goto exit_drop_table;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb>=0 && iDb<db->nDb );
  sqlite3SchemaWritable(pParse, iDb);

  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
  ** it is initialized.
  */
  if( IsVirtual(pTab) && sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto exit_drop_table;
  }
................................................................................

    /* Fill the index with data and reparse the schema. Code an OP_Expire
    ** to invalidate all pre-compiled statements.
    */
    if( pTblName ){
      sqlite3RefillIndex(pParse, pIndex, iMem);
      sqlite3ChangeCookie(pParse, iDb);
      sqlite3VdbeAddParseSchemaOp(pParse, iDb,
         sqlite3MPrintf(db, "name='%q' AND type='index'", pIndex->zName));
      sqlite3VdbeAddOp0(v, OP_Expire);
    }

    sqlite3VdbeJumpHere(v, pIndex->tnum);
  }

................................................................................
  }
  if( pIndex->idxType!=SQLITE_IDXTYPE_APPDEF ){
    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
      "or PRIMARY KEY constraint cannot be dropped", 0);
    goto exit_drop_index;
  }
  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
  sqlite3SchemaWritable(pParse, iDb);
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_INDEX;
    Table *pTab = pIndex->pTable;
    const char *zDb = db->aDb[iDb].zDbSName;
    const char *zTab = SCHEMA_TABLE(iDb);
    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){

  sqlite3HashClear(&pSchema->fkeyHash);
  pSchema->pSeqTab = 0;
  if( pSchema->schemaFlags & DB_SchemaLoaded ){
    pSchema->iGeneration++;
    pSchema->schemaFlags &= ~DB_SchemaLoaded;
  }
}

/*






































































































** Find and return the schema associated with a BTree.  Create
** a new one if necessary.
*/
Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
  Schema * p;
  if( pBt ){

    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
  }else{
    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
  }
  if( !p ){
    sqlite3OomFault(db);
  }else if ( 0==p->file_format ){
    sqlite3HashInit(&p->tblHash);
    sqlite3HashInit(&p->idxHash);
    sqlite3HashInit(&p->trigHash);
    sqlite3HashInit(&p->fkeyHash);
    p->enc = SQLITE_UTF8;

  }
  return p;
}

  sqlite3HashClear(&pSchema->fkeyHash);
  pSchema->pSeqTab = 0;
  if( pSchema->schemaFlags & DB_SchemaLoaded ){
    pSchema->iGeneration++;
    pSchema->schemaFlags &= ~DB_SchemaLoaded;
  }
}

/*
** Global linked list of sharable Schema objects. Read and write access must
** be protected by the SQLITE_MUTEX_STATIC_MASTER mutex.
*/
static Schema *SQLITE_WSD sharedSchemaList = 0;

/*
** Check that the schema of db iDb is writable (either because it is the temp
** db schema or because the db handle was opened without
** SQLITE_OPEN_REUSE_SCHEMA). If so, do nothing. Otherwise, leave an 
** error in the Parse object.
*/
void sqlite3SchemaWritable(Parse *pParse, int iDb){
  if( iDb!=1 && (pParse->db->openFlags & SQLITE_OPEN_REUSE_SCHEMA) ){
    sqlite3ErrorMsg(pParse, "attempt to modify read-only schema");
  }
}

/*
** Replace the Schema object currently associated with database iDb with
** an empty schema object, ready to be populated. If there are multiple
** users of the Schema, this means decrementing the current objects ref
** count and replacing it with a pointer to a new, empty, object. Or, if
** the database handle passed as the first argument of the schema object 
** is the only user, remove it from the shared list (if applicable) and 
** clear it in place.
*/
void sqlite3SchemaUnuse(sqlite3 *db, int iDb){
  Db *pDb = &db->aDb[iDb];
  Schema *pSchema;
  assert( iDb!=1 );
  if( (pSchema = pDb->pSchema) ){

    if( (db->openFlags & SQLITE_OPEN_REUSE_SCHEMA) ){
      sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
      assert( pSchema->nRef>=1 );
      if( pSchema->nRef==1 ){
        Schema **pp;
        for(pp=&sharedSchemaList; (*pp); pp=&(*pp)->pNext){
          if( *pp==pSchema ){
            *pp = pSchema->pNext;
            break;
          }
        }
        pSchema->pNext = 0;
      }else{
        assert( db->openFlags & SQLITE_OPEN_REUSE_SCHEMA );
        pSchema->nRef--;
        pDb->pSchema = pSchema = 0;
      }
      sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
    }

    if( pSchema==0 ){
      db->aDb[iDb].pSchema = sqlite3SchemaGet(db, 0);
    }else{
      sqlite3SchemaClear(pSchema);
    }
  }
}

/*
** The schema for database iDb of database handle db, which was opened
** with SQLITE_OPEN_REUSE_SCHEMA, has just been parsed. This function
** checks the global list (sharedSchemaList) for a matching schema and,
** if one is found, frees the newly parsed Schema object and adds a pointer 
** to the existing shared schema in its place. Or, if there is no matching
** schema in the list, then the new schema is added to it.
*/
void sqlite3SchemaReuse(sqlite3 *db, int iDb){
  Schema *pSchema = db->aDb[iDb].pSchema;
  Schema *p;
  assert( pSchema && iDb!=1 );

  sqlite3_mutex_enter( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );
  for(p=sharedSchemaList; p; p=p->pNext){
    if( p->cksum==pSchema->cksum 
        && p->schema_cookie==pSchema->schema_cookie 
      ){
      break;
    }
  }
  if( !p ){
    /* No matching schema was found. */
    pSchema->pNext = sharedSchemaList;
    sharedSchemaList = pSchema;
  }else{
    /* Found a matching schema. Increase its ref count. */
    p->nRef++;
  }
  sqlite3_mutex_leave( sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER) );

  /* If a matching schema was found in the shared schema list, free the
  ** schema object just parsed, and add a pointer to the matching schema
  ** to the db handle.  */
  if( p ){
    sqlite3SchemaClear(pSchema);
    sqlite3DbFree(0, pSchema);
    db->aDb[iDb].pSchema = p;
  }
}

/*
** Find and return the schema associated with a BTree.  Create
** a new one if necessary.
*/
Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
  Schema * p;

  if( pBt && (db->openFlags & SQLITE_OPEN_REUSE_SCHEMA)==0 ){
    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
  }else{
    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
  }
  if( !p ){
    sqlite3OomFault(db);
  }else if ( 0==p->file_format ){
    sqlite3HashInit(&p->tblHash);
    sqlite3HashInit(&p->idxHash);
    sqlite3HashInit(&p->trigHash);
    sqlite3HashInit(&p->fkeyHash);
    p->enc = SQLITE_UTF8;
    p->nRef = 1;
  }
  return p;
}

  /* Close all database connections */
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){
      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){




        pDb->pSchema = 0;
      }
    }
  }
  /* Clear the TEMP schema separately and last */
  if( db->aDb[1].pSchema ){
    sqlite3SchemaClear(db->aDb[1].pSchema);

  /* Close all database connections */
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){
      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){
        if( db->openFlags & SQLITE_OPEN_REUSE_SCHEMA ){
          sqlite3SchemaUnuse(db, j);
          sqlite3DbFree(0, pDb->pSchema);
        }
        pDb->pSchema = 0;
      }
    }
  }
  /* Clear the TEMP schema separately and last */
  if( db->aDb[1].pSchema ){
    sqlite3SchemaClear(db->aDb[1].pSchema);

    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
    if( zExtra ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);
    sqlite3DbFree(db, *pData->pzErrMsg);
    *pData->pzErrMsg = z;
  }
  pData->rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_CORRUPT_BKPT;
}





















/*
** This is the callback routine for the code that initializes the
** database.  See sqlite3Init() below for additional information.
** This routine is also called from the OP_ParseSchema opcode of the VDBE.
**
** Each callback contains the following information:
................................................................................
      ** safely ignore the index on the permanent table.
      */
      /* Do Nothing */;
    }else if( sqlite3GetInt32(argv[1], &pIndex->tnum)==0 ){
      corruptSchema(pData, argv[0], "invalid rootpage");
    }
  }










  return 0;
}

/*
** Attempt to read the database schema and initialize internal
** data structures for a single database file.  The index of the
** database file is given by iDb.  iDb==0 is used for the main
................................................................................
    ** of the schema was loaded before the error occurred. The primary
    ** purpose of this is to allow access to the sqlite_master table
    ** even when its contents have been corrupted.
    */
    DbSetProperty(db, iDb, DB_SchemaLoaded);
    rc = SQLITE_OK;
  }





  /* Jump here for an error that occurs after successfully allocating
  ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
  ** before that point, jump to error_out.
  */
initone_error_out:
  if( openedTransaction ){

    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
    if( zExtra ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);
    sqlite3DbFree(db, *pData->pzErrMsg);
    *pData->pzErrMsg = z;
  }
  pData->rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_CORRUPT_BKPT;
}

/*
** Update the Schema.cksum checksum to account for the database object
** specified by the three arguments following the first.
*/
void schemaUpdateChecksum(
  Schema *pSchema,                /* Schema object being parsed */
  const char *zName,              /* Name of new database object */
  const char *zRoot,              /* Root page of new database object */
  const char *zSql                /* SQL used to create new database object */
){
  int i;
  u64 cksum = pSchema->cksum;
  if( zName ){
    for(i=0; zName[i]; i++) cksum += (cksum<<3) + zName[i];
  }
  if( zRoot ) for(i=0; zRoot[i]; i++) cksum += (cksum<<3) + zRoot[i];
  if( zSql ) for(i=0; zSql[i]; i++) cksum += (cksum<<3) + zSql[i];
  pSchema->cksum = cksum;
}

/*
** This is the callback routine for the code that initializes the
** database.  See sqlite3Init() below for additional information.
** This routine is also called from the OP_ParseSchema opcode of the VDBE.
**
** Each callback contains the following information:
................................................................................
      ** safely ignore the index on the permanent table.
      */
      /* Do Nothing */;
    }else if( sqlite3GetInt32(argv[1], &pIndex->tnum)==0 ){
      corruptSchema(pData, argv[0], "invalid rootpage");
    }
  }

  if( iDb!=1 && (db->openFlags & SQLITE_OPEN_REUSE_SCHEMA) ){
    /* If this schema might be used by multiple connections, ensure that
    ** the affinity string is allocated here. Otherwise, there might be
    ** a race condition where two threads attempt to allocate it
    ** simultaneously.  */
    Index *pIndex = sqlite3FindIndex(db, argv[0], db->aDb[iDb].zDbSName);
    if( pIndex ) sqlite3IndexAffinityStr(db, pIndex);
    schemaUpdateChecksum(db->aDb[iDb].pSchema, argv[0], argv[1], argv[2]);
  }
  return 0;
}

/*
** Attempt to read the database schema and initialize internal
** data structures for a single database file.  The index of the
** database file is given by iDb.  iDb==0 is used for the main
................................................................................
    ** of the schema was loaded before the error occurred. The primary
    ** purpose of this is to allow access to the sqlite_master table
    ** even when its contents have been corrupted.
    */
    DbSetProperty(db, iDb, DB_SchemaLoaded);
    rc = SQLITE_OK;
  }

  if( iDb!=1 && (db->openFlags & SQLITE_OPEN_REUSE_SCHEMA) ){
    sqlite3SchemaReuse(db, iDb);
  }

  /* Jump here for an error that occurs after successfully allocating
  ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
  ** before that point, jump to error_out.
  */
initone_error_out:
  if( openedTransaction ){

#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */

/* Reserved:                         0x00F00000 */



/*
** CAPI3REF: Device Characteristics
**
** The xDeviceCharacteristics method of the [sqlite3_io_methods]
** object returns an integer which is a vector of these
** bit values expressing I/O characteristics of the mass storage

#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */

/* Reserved:                         0x00F00000 */
#define SQLITE_OPEN_REUSE_SCHEMA     0x01000000  /* Ok for sqlite3_open_v2() */


/*
** CAPI3REF: Device Characteristics
**
** The xDeviceCharacteristics method of the [sqlite3_io_methods]
** object returns an integer which is a vector of these
** bit values expressing I/O characteristics of the mass storage

  Hash trigHash;       /* All triggers indexed by name */
  Hash fkeyHash;       /* All foreign keys by referenced table name */
  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
  u8 file_format;      /* Schema format version for this file */
  u8 enc;              /* Text encoding used by this database */
  u16 schemaFlags;     /* Flags associated with this schema */
  int cache_size;      /* Number of pages to use in the cache */




};

/*
** These macros can be used to test, set, or clear bits in the
** Db.pSchema->flags field.
*/
#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->schemaFlags&(P))==(P))
................................................................................
int sqlite3FindDbName(sqlite3 *, const char *);
int sqlite3AnalysisLoad(sqlite3*,int iDB);
void sqlite3DeleteIndexSamples(sqlite3*,Index*);
void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
void sqlite3SchemaClear(void *);



Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
KeyInfo *sqlite3KeyInfoAlloc(sqlite3*,int,int);
void sqlite3KeyInfoUnref(KeyInfo*);
KeyInfo *sqlite3KeyInfoRef(KeyInfo*);
KeyInfo *sqlite3KeyInfoOfIndex(Parse*, Index*);
#ifdef SQLITE_DEBUG

  Hash trigHash;       /* All triggers indexed by name */
  Hash fkeyHash;       /* All foreign keys by referenced table name */
  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
  u8 file_format;      /* Schema format version for this file */
  u8 enc;              /* Text encoding used by this database */
  u16 schemaFlags;     /* Flags associated with this schema */
  int cache_size;      /* Number of pages to use in the cache */

  int nRef;            /* Number of connections using this schema */
  u64 cksum;           /* Checksum for this database schema */
  Schema *pNext;       /* Next schema in shared schema list */
};

/*
** These macros can be used to test, set, or clear bits in the
** Db.pSchema->flags field.
*/
#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->schemaFlags&(P))==(P))
................................................................................
int sqlite3FindDbName(sqlite3 *, const char *);
int sqlite3AnalysisLoad(sqlite3*,int iDB);
void sqlite3DeleteIndexSamples(sqlite3*,Index*);
void sqlite3DefaultRowEst(Index*);
void sqlite3RegisterLikeFunctions(sqlite3*, int);
int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
void sqlite3SchemaClear(void *);
void sqlite3SchemaUnuse(sqlite3*, int);
void sqlite3SchemaReuse(sqlite3*, int);
void sqlite3SchemaWritable(Parse*, int);
Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
KeyInfo *sqlite3KeyInfoAlloc(sqlite3*,int,int);
void sqlite3KeyInfoUnref(KeyInfo*);
KeyInfo *sqlite3KeyInfoRef(KeyInfo*);
KeyInfo *sqlite3KeyInfoOfIndex(Parse*, Index*);
#ifdef SQLITE_DEBUG

      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b ){
        flags |= SQLITE_OPEN_URI;
      }else{
        flags &= ~SQLITE_OPEN_URI;
      }








    }else{
      Tcl_AppendResult(interp, "unknown option: ", zArg, (char*)0);
      return TCL_ERROR;
    }
  }
  if( objc<3 || (objc&1)!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv,
      "HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"

#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_CODEC_FROM_TCL)
      " ?-key CODECKEY?"
#endif
    );
    return TCL_ERROR;
  }
  zErrMsg = 0;

      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b ){
        flags |= SQLITE_OPEN_URI;
      }else{
        flags &= ~SQLITE_OPEN_URI;
      }
    }else if( strcmp(zArg, "-reuse-schema")==0 ){
      int b;
      if( Tcl_GetBooleanFromObj(interp, objv[i+1], &b) ) return TCL_ERROR;
      if( b ){
        flags |= SQLITE_OPEN_REUSE_SCHEMA;
      }else{
        flags &= ~SQLITE_OPEN_REUSE_SCHEMA;
      }
    }else{
      Tcl_AppendResult(interp, "unknown option: ", zArg, (char*)0);
      return TCL_ERROR;
    }
  }
  if( objc<3 || (objc&1)!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv,
      "HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
      " ?-reuse-schema BOOLEAN?"
#if defined(SQLITE_HAS_CODEC) && !defined(SQLITE_OMIT_CODEC_FROM_TCL)
      " ?-key CODECKEY?"
#endif
    );
    return TCL_ERROR;
  }
  zErrMsg = 0;

    testcase( z==0 );
    sqlite3NestedParse(pParse,
       "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
       db->aDb[iDb].zDbSName, MASTER_NAME, zName,
       pTrig->table, z);
    sqlite3DbFree(db, z);
    sqlite3ChangeCookie(pParse, iDb);
    sqlite3VdbeAddParseSchemaOp(v, iDb,
        sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName));
  }

  if( db->init.busy ){
    Trigger *pLink = pTrig;
    Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
................................................................................
  Table   *pTable;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
  assert( iDb>=0 && iDb<db->nDb );

  pTable = tableOfTrigger(pTrigger);
  assert( pTable );
  assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_TRIGGER;
    const char *zDb = db->aDb[iDb].zDbSName;

    testcase( z==0 );
    sqlite3NestedParse(pParse,
       "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
       db->aDb[iDb].zDbSName, MASTER_NAME, zName,
       pTrig->table, z);
    sqlite3DbFree(db, z);
    sqlite3ChangeCookie(pParse, iDb);
    sqlite3VdbeAddParseSchemaOp(pParse, iDb,
        sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName));
  }

  if( db->init.busy ){
    Trigger *pLink = pTrig;
    Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
................................................................................
  Table   *pTable;
  Vdbe *v;
  sqlite3 *db = pParse->db;
  int iDb;

  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
  assert( iDb>=0 && iDb<db->nDb );
  sqlite3SchemaWritable(pParse, iDb);
  pTable = tableOfTrigger(pTrigger);
  assert( pTable );
  assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_TRIGGER;
    const char *zDb = db->aDb[iDb].zDbSName;

    ** The buggy behavior is required for binary compatibility with some
    ** legacy applications. */
    iDb = sqlite3FindDb(pParse->db, pNm);
    if( iDb<0 ) iDb = 0;
#endif
  }
  if( iDb!=1 ){

    sqlite3VdbeAddOp1(v, OP_Vacuum, iDb);
    sqlite3VdbeUsesBtree(v, iDb);
  }
  return;
}

/*

    ** The buggy behavior is required for binary compatibility with some
    ** legacy applications. */
    iDb = sqlite3FindDb(pParse->db, pNm);
    if( iDb<0 ) iDb = 0;
#endif
  }
  if( iDb!=1 ){
    sqlite3SchemaWritable(pParse, iDb);
    sqlite3VdbeAddOp1(v, OP_Vacuum, iDb);
    sqlite3VdbeUsesBtree(v, iDb);
  }
  return;
}

/*

  void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N);
  void sqlite3VdbeVerifyNoResultRow(Vdbe *p);
#else
# define sqlite3VdbeVerifyNoMallocRequired(A,B)
# define sqlite3VdbeVerifyNoResultRow(A)
#endif
VdbeOp *sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp, int iLineno);
void sqlite3VdbeAddParseSchemaOp(Vdbe*,int,char*);
void sqlite3VdbeChangeOpcode(Vdbe*, u32 addr, u8);
void sqlite3VdbeChangeP1(Vdbe*, u32 addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, u32 addr, int P2);
void sqlite3VdbeChangeP3(Vdbe*, u32 addr, int P3);
void sqlite3VdbeChangeP5(Vdbe*, u16 P5);
void sqlite3VdbeJumpHere(Vdbe*, int addr);
int sqlite3VdbeChangeToNoop(Vdbe*, int addr);

  void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N);
  void sqlite3VdbeVerifyNoResultRow(Vdbe *p);
#else
# define sqlite3VdbeVerifyNoMallocRequired(A,B)
# define sqlite3VdbeVerifyNoResultRow(A)
#endif
VdbeOp *sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp, int iLineno);
void sqlite3VdbeAddParseSchemaOp(Parse*,int,char*);
void sqlite3VdbeChangeOpcode(Vdbe*, u32 addr, u8);
void sqlite3VdbeChangeP1(Vdbe*, u32 addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, u32 addr, int P2);
void sqlite3VdbeChangeP3(Vdbe*, u32 addr, int P3);
void sqlite3VdbeChangeP5(Vdbe*, u16 P5);
void sqlite3VdbeJumpHere(Vdbe*, int addr);
int sqlite3VdbeChangeToNoop(Vdbe*, int addr);

** Add an OP_ParseSchema opcode.  This routine is broken out from
** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees
** as having been used.
**
** The zWhere string must have been obtained from sqlite3_malloc().
** This routine will take ownership of the allocated memory.
*/
void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere){

  int j;

  sqlite3VdbeAddOp4(p, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
}

/*
** Add an opcode that includes the p4 value as an integer.
*/

** Add an OP_ParseSchema opcode.  This routine is broken out from
** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees
** as having been used.
**
** The zWhere string must have been obtained from sqlite3_malloc().
** This routine will take ownership of the allocated memory.
*/
void sqlite3VdbeAddParseSchemaOp(Parse *pParse, int iDb, char *zWhere){
  Vdbe *p = pParse->pVdbe;
  int j;
  sqlite3SchemaWritable(pParse, iDb);
  sqlite3VdbeAddOp4(p, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
}

/*
** Add an opcode that includes the p4 value as an integer.
*/

    );
    sqlite3DbFree(db, zStmt);
    v = sqlite3GetVdbe(pParse);
    sqlite3ChangeCookie(pParse, iDb);

    sqlite3VdbeAddOp0(v, OP_Expire);
    zWhere = sqlite3MPrintf(db, "name='%q' AND type='table'", pTab->zName);
    sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);

    iReg = ++pParse->nMem;
    sqlite3VdbeLoadString(v, iReg, pTab->zName);
    sqlite3VdbeAddOp2(v, OP_VCreate, iDb, iReg);
  }

  /* If we are rereading the sqlite_master table create the in-memory

    );
    sqlite3DbFree(db, zStmt);
    v = sqlite3GetVdbe(pParse);
    sqlite3ChangeCookie(pParse, iDb);

    sqlite3VdbeAddOp0(v, OP_Expire);
    zWhere = sqlite3MPrintf(db, "name='%q' AND type='table'", pTab->zName);
    sqlite3VdbeAddParseSchemaOp(pParse, iDb, zWhere);

    iReg = ++pParse->nMem;
    sqlite3VdbeLoadString(v, iReg, pTab->zName);
    sqlite3VdbeAddOp2(v, OP_VCreate, iDb, iReg);
  }

  /* If we are rereading the sqlite_master table create the in-memory

# 2017 August 9
#
# 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.
#
#***********************************************************************
#
#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix reuse1


forcedelete test.db2
sqlite3 db2 test.db2

do_execsql_test 1.0 {
  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
  CREATE INDEX i1 ON t1(z);
  PRAGMA schema_version;
} {2}

do_execsql_test -db db2 1.1 {
  CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z);
  CREATE INDEX i1 ON t1(z);
  PRAGMA schema_version;
} {2}

do_test 1.2 {
  db close
  db2 close
  sqlite3 db2 test.db2 -reuse-schema 1
  sqlite3 db  test.db -reuse-schema 1
} {}

do_execsql_test -db db2 1.3.1 {
  INSERT INTO t1 VALUES(1, 2, 3);
  INSERT INTO t1 VALUES(4, 5, 6);
}

do_execsql_test 1.3.2 {
  SELECT * FROM t1;
  PRAGMA integrity_check;
} {ok}

do_execsql_test -db db2 1.3.3 {
  SELECT * FROM t1;
  PRAGMA integrity_check;
} {1 2 3 4 5 6 ok}

sqlite3 db3 test.db2
do_execsql_test -db db3 1.4.1 {
  ALTER TABLE t1 ADD COLUMN a;
}
do_execsql_test -db db2 1.4.2 {
  SELECT * FROM t1;
} {1 2 3 {} 4 5 6 {}}
do_execsql_test 1.4.3 {
  SELECT * FROM t1;
} {}

db3 close
sqlite3 db3 test.db
do_execsql_test -db db3 1.5.0 {
  CREATE TRIGGER tr1 AFTER INSERT ON t1 BEGIN
    SELECT 1, 2, 3;
  END;
}

# Check that the schema cannot be modified if the db was opened with
# SQLITE_OPEN_REUSE_SCHEMA.
#
foreach {tn sql} {
  1  { CREATE TABLE t2(x, y) }
  2  { CREATE INDEX i2 ON t1(z) }
  3  { CREATE VIEW v2 AS SELECT * FROM t2 }
  4  { ALTER TABLE t1 RENAME TO t3 }
  5  { ALTER TABLE t1 ADD COLUMN xyz }
  6  { VACUUM }
  7  { DROP INDEX i1 }
  8  { DROP TABLE t1 }
  9  { DROP TRIGGER tr1 }
  10 { ANALYZE }
} {
  do_catchsql_test 1.5.$tn $sql {1 {attempt to modify read-only schema}}
}

finish_test

# $Id: tclsqlite.test,v 1.73 2009/03/16 13:19:36 danielk1977 Exp $

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

# Check the error messages generated by tclsqlite
#
set r "sqlite_orig HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN? ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
if {[sqlite3 -has-codec]} {
  append r " ?-key CODECKEY?"
}
do_test tcl-1.1 {
  set v [catch {sqlite3 bogus} msg]
  regsub {really_sqlite3} $msg {sqlite3} msg
  lappend v $msg

# $Id: tclsqlite.test,v 1.73 2009/03/16 13:19:36 danielk1977 Exp $

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

# Check the error messages generated by tclsqlite
#
set r "sqlite_orig HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN? ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN? ?-reuse-schema BOOLEAN?"
if {[sqlite3 -has-codec]} {
  append r " ?-key CODECKEY?"
}
do_test tcl-1.1 {
  set v [catch {sqlite3 bogus} msg]
  regsub {really_sqlite3} $msg {sqlite3} msg
  lappend v $msg