SQLite

    zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", ((u8*)tname.z) - zSql, zSql, 
       zTableName, tname.z+tname.n);
    sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
  }
}

/*
** This C function implements an SQL user function that is used by SQL code
** generated by the ALTER TABLE ... RENAME command to modify the definition
** of any foreign key constraints that use the table being renamed as the 
** parent table. It is passed three arguments:
**
**   1) The complete text of the CREATE TABLE statement being modified,
**   2) The old name of the table being renamed, and
**   3) The new name of the table being renamed.
**
** It returns the new CREATE TABLE statement. For example:
**
**   sqlite_rename_parent('CREATE TABLE t1(a REFERENCES t2)', 't2', 't3')
**       -> 'CREATE TABLE t1(a REFERENCES t3)'
*/
#ifndef SQLITE_OMIT_FOREIGN_KEY
static void renameParentFunc(
  sqlite3_context *context,
  int NotUsed,
  sqlite3_value **argv
){
  sqlite3 *db = sqlite3_context_db_handle(context);
  char *zOutput = 0;
  char *zResult;
  unsigned char const *zInput = sqlite3_value_text(argv[0]);
  unsigned char const *zOld = sqlite3_value_text(argv[1]);
  unsigned char const *zNew = sqlite3_value_text(argv[2]);

  unsigned const char *z;         /* Pointer to token */
  int n;                          /* Length of token z */
  int token;                      /* Type of token */

  for(z=zInput; *z; z=z+n){
    n = sqlite3GetToken(z, &token);
    if( token==TK_REFERENCES ){
      char *zParent;
      do {
        z += n;
        n = sqlite3GetToken(z, &token);
      }while( token==TK_SPACE );

      zParent = sqlite3DbStrNDup(db, (const char *)z, n);
      sqlite3Dequote(zParent);
      if( 0==sqlite3StrICmp((const char *)zOld, zParent) ){
        char *zOut = sqlite3MPrintf(db, "%s%.*s\"%w\"", 
            (zOutput?zOutput:""), z-zInput, zInput, (const char *)zNew
        );
        sqlite3DbFree(db, zOutput);
        zOutput = zOut;
        zInput = &z[n];
      }
      sqlite3DbFree(db, zParent);
    }
  }

  zResult = sqlite3MPrintf(db, "%s%s", (zOutput?zOutput:""), zInput), 
  sqlite3_result_text(context, zResult, -1, SQLITE_DYNAMIC);
  sqlite3DbFree(db, zOutput);
}
#endif

#ifndef SQLITE_OMIT_TRIGGER
/* This function is used by SQL generated to implement the
** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER 
** statement. The second is a table name. The table name in the CREATE 
** TRIGGER statement is replaced with the third argument and the result 
** returned. This is analagous to renameTableFunc() above, except for CREATE
** TRIGGER, not CREATE INDEX and CREATE TABLE.

void sqlite3AlterFunctions(sqlite3 *db){
  sqlite3CreateFunc(db, "sqlite_rename_table", 2, SQLITE_UTF8, 0,
                         renameTableFunc, 0, 0);
#ifndef SQLITE_OMIT_TRIGGER
  sqlite3CreateFunc(db, "sqlite_rename_trigger", 2, SQLITE_UTF8, 0,
                         renameTriggerFunc, 0, 0);
#endif
#ifndef SQLITE_OMIT_FOREIGN_KEY
  sqlite3CreateFunc(db, "sqlite_rename_parent", 3, SQLITE_UTF8, 0,
                         renameParentFunc, 0, 0);
#endif
}

/*
** This function is used to create the text of expressions of the form:
**
**   name=<constant1> OR name=<constant2> OR ...
**
** If argument zWhere is NULL, then a pointer string containing the text 
** "name=<constant>" is returned, where <constant> is the quoted version
** of the string passed as argument zConstant. The returned buffer is
** allocated using sqlite3DbMalloc(). It is the responsibility of the
** caller to ensure that it is eventually freed.
**
** If argument zWhere is not NULL, then the string returned is 
** "<where> OR name=<constant>", where <where> is the contents of zWhere.
** In this case zWhere is passed to sqlite3DbFree() before returning.
** 
*/
static char *whereOrName(sqlite3 *db, char *zWhere, char *zConstant){
  char *zNew;
  if( !zWhere ){
    zNew = sqlite3MPrintf(db, "name=%Q", zConstant);
  }else{
    zNew = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, zConstant);
    sqlite3DbFree(db, zWhere);
  }
  return zNew;
}

/*
** Generate the text of a WHERE expression which can be used to select all
** tables that have foreign key constraints that refer to table pTab (i.e.
** constraints for which pTab is the parent table) from the sqlite_master
** table.
*/
static char *whereForeignKeys(Parse *pParse, Table *pTab){
  FKey *p;
  char *zWhere = 0;
  for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
    zWhere = whereOrName(pParse->db, zWhere, p->pFrom->zName);
  }
  return zWhere;
}

/*
** Generate the text of a WHERE expression which can be used to select all
** temporary triggers on table pTab from the sqlite_temp_master table. If
** table pTab has no temporary triggers, or is itself stored in the 
** temporary database, NULL is returned.
*/
static char *whereTempTriggers(Parse *pParse, Table *pTab){
  Trigger *pTrig;
  char *zWhere = 0;

  const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */

  /* If the table is not located in the temp-db (in which case NULL is 
  ** returned, loop through the tables list of triggers. For each trigger
  ** that is not part of the temp-db schema, add a clause to the WHERE 
  ** expression being built up in zWhere.
  */
  if( pTab->pSchema!=pTempSchema ){
    sqlite3 *db = pParse->db;
    for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
      if( pTrig->pSchema==pTempSchema ){




        zWhere = whereOrName(db, zWhere, pTrig->zName);


      }
    }
  }
  return zWhere;
}

/*

  for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
    int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
    assert( iTrigDb==iDb || iTrigDb==1 );
    sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->zName, 0);
  }
#endif

  /* 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;
  sqlite3VdbeAddOp4(v, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);

    sqlite3MayAbort(pParse);
  }
#endif

  /* figure out how many UTF-8 characters are in zName */
  zTabName = pTab->zName;
  nTabName = sqlite3Utf8CharLen(zTabName, -1);

#ifndef SQLITE_OMIT_FOREIGN_KEY
  if( db->flags&SQLITE_ForeignKeys ){
    /* If foreign-key support is enabled, rewrite the CREATE TABLE 
    ** statements corresponding to all child tables of foreign key constraints
    ** for which the renamed table is the parent table.  */
    if( (zWhere=whereForeignKeys(pParse, pTab))!=0 ){
      sqlite3NestedParse(pParse, 
          "UPDATE sqlite_master SET "
              "sql = sqlite_rename_parent(sql, %Q, %Q) "
              "WHERE %s;", zTabName, zName, zWhere);
      sqlite3DbFree(db, zWhere);
    }
  }
#endif

  /* Modify the sqlite_master table to use the new table name. */
  sqlite3NestedParse(pParse,
      "UPDATE %Q.%s SET "
#ifdef SQLITE_OMIT_TRIGGER
          "sql = sqlite_rename_table(sql, %Q), "
#else

  if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
    sqlite3NestedParse(pParse, 
        "UPDATE sqlite_temp_master SET "
            "sql = sqlite_rename_trigger(sql, %Q), "
            "tbl_name = %Q "
            "WHERE %s;", zName, zName, zWhere);
    sqlite3DbFree(db, zWhere);
  }
#endif

#ifndef SQLITE_OMIT_FOREIGN_KEY
  if( db->flags&SQLITE_ForeignKeys ){
    FKey *p;
    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
      Table *pFrom = p->pFrom;
      if( pFrom!=pTab ){
        reloadTableSchema(pParse, p->pFrom, pFrom->zName);
      }
    }
  }
#endif

  /* Drop and reload the internal table schema. */
  reloadTableSchema(pParse, pTab, zName);

exit_rename_table:

**
** Calling this function with table "t1" as an argument returns a pointer
** to the FKey structure representing the foreign key constraint on table
** "t2". Calling this function with "t2" as the argument would return a
** NULL pointer (as there are no FK constraints for which t2 is the parent
** table).
*/
FKey *sqlite3FkReferences(Table *pTab){
  int nName = sqlite3Strlen30(pTab->zName);
  return (FKey *)sqlite3HashFind(&pTab->pSchema->fkeyHash, pTab->zName, nName);
}

/*
** The second argument is a Trigger structure allocated by the 
** fkActionTrigger() routine. This function deletes the Trigger structure

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

    sqlite3DbFree(db, aiFree);
  }

  /* Loop through all the foreign key constraints that refer to this table */
  for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
    int iGoto;                    /* Address of OP_Goto instruction */
    Index *pIdx = 0;              /* Foreign key index for pFKey */
    SrcList *pSrc;
    int *aiCol = 0;

    if( !pFKey->isDeferred && !pParse->pToplevel && !pParse->isMultiWrite ){
      assert( regOld==0 && regNew!=0 );

  u32 mask = 0;
  if( pParse->db->flags&SQLITE_ForeignKeys ){
    FKey *p;
    int i;
    for(p=pTab->pFKey; p; p=p->pNextFrom){
      for(i=0; i<p->nCol; i++) mask |= COLUMN_MASK(p->aCol[i].iFrom);
    }
    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
      Index *pIdx = 0;
      locateFkeyIndex(0, pTab, p, &pIdx, 0);
      if( pIdx ){
        for(i=0; i<pIdx->nColumn; i++) mask |= COLUMN_MASK(pIdx->aiColumn[i]);
      }
    }
  }

*/
int sqlite3FkRequired(
  Parse *pParse,                  /* Parse context */
  Table *pTab,                    /* Table being modified */
  ExprList *pChanges              /* Non-NULL for UPDATE operations */
){
  if( pParse->db->flags&SQLITE_ForeignKeys ){
    if( sqlite3FkReferences(pTab) || pTab->pFKey ) return 1;
  }
  return 0;
}

/*
** This function is called when an UPDATE or DELETE operation is being 
** compiled on table pTab, which is the parent table of foreign-key pFKey.

){
  /* If foreign-key support is enabled, iterate through all FKs that 
  ** refer to table pTab. If there is an action associated with the FK 
  ** for this operation (either update or delete), invoke the associated 
  ** trigger sub-program.  */
  if( pParse->db->flags&SQLITE_ForeignKeys ){
    FKey *pFKey;                  /* Iterator variable */
    for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
      Trigger *pAction = fkActionTrigger(pParse, pTab, pFKey, pChanges);
      if( pAction ){
        sqlite3CodeRowTriggerDirect(pParse, pAction, pTab, regOld, OE_Abort, 0);
      }
    }
  }
}

** provided (enforcement of FK constraints requires the triggers sub-system).
*/
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
  void sqlite3FkCheck(Parse*, Table*, ExprList*, int, int);
  void sqlite3FkActions(Parse*, Table*, ExprList*, int);
  int sqlite3FkRequired(Parse*, Table*, ExprList*);
  u32 sqlite3FkOldmask(Parse*, Table*, ExprList*);
  FKey *sqlite3FkReferences(Table *);
#else
  #define sqlite3FkCheck(a,b,c,d,e)
  #define sqlite3FkActions(a,b,c,d)
  #define sqlite3FkRequired(a,b,c) 0
  #define sqlite3FkOldmask(a,b,c)  0
#endif
#ifndef SQLITE_OMIT_FOREIGN_KEY

    PRAGMA foreign_keys = off;
    ALTER TABLE t2 ADD COLUMN h DEFAULT 'text' REFERENCES t1;
    PRAGMA foreign_keys = on;
    SELECT sql FROM sqlite_master WHERE name='t2';
  }
} {{CREATE TABLE t2(a, b, c REFERENCES t1, d DEFAULT NULL REFERENCES t1, e REFERENCES t1 DEFAULT NULL, h DEFAULT 'text' REFERENCES t1)}}


# Test the sqlite_rename_parent() function directly.
#
proc test_rename_parent {zCreate zOld zNew} {
  db eval {SELECT sqlite_rename_parent($zCreate, $zOld, $zNew)}
}
do_test fkey2-14.2.1.1 {
  test_rename_parent {CREATE TABLE t1(a REFERENCES t2)} t2 t3
} {{CREATE TABLE t1(a REFERENCES "t3")}}
do_test fkey2-14.2.1.2 {
  test_rename_parent {CREATE TABLE t1(a REFERENCES t2)} t4 t3
} {{CREATE TABLE t1(a REFERENCES t2)}}
do_test fkey2-14.2.1.3 {
  test_rename_parent {CREATE TABLE t1(a REFERENCES "t2")} t2 t3
} {{CREATE TABLE t1(a REFERENCES "t3")}}

# Test ALTER TABLE RENAME TABLE a bit.
#
do_test fkey2-14.2.2.1 {
  drop_all_tables
  execsql {
    CREATE TABLE t1(a PRIMARY KEY, b REFERENCES t1);
    CREATE TABLE t2(a PRIMARY KEY, b REFERENCES t1, c REFERENCES t2);
    CREATE TABLE t3(a REFERENCES t1, b REFERENCES t2, c REFERENCES t1);
  }
  execsql { SELECT sql FROM sqlite_master WHERE type = 'table'}
} [list \
  {CREATE TABLE t1(a PRIMARY KEY, b REFERENCES t1)}                     \
  {CREATE TABLE t2(a PRIMARY KEY, b REFERENCES t1, c REFERENCES t2)}    \
  {CREATE TABLE t3(a REFERENCES t1, b REFERENCES t2, c REFERENCES t1)}  \
]
do_test fkey2-14.2.2.2 {
  execsql { ALTER TABLE t1 RENAME TO t4 }
  execsql { SELECT sql FROM sqlite_master WHERE type = 'table'}
} [list \
  {CREATE TABLE "t4"(a PRIMARY KEY, b REFERENCES "t4")}                     \
  {CREATE TABLE t2(a PRIMARY KEY, b REFERENCES "t4", c REFERENCES t2)}    \
  {CREATE TABLE t3(a REFERENCES "t4", b REFERENCES t2, c REFERENCES "t4")}  \
]
do_test fkey2-14.2.2.3 {
  catchsql { INSERT INTO t3 VALUES(1, 2, 3) }
} {1 {foreign key constraint failed}}
do_test fkey2-14.2.2.4 {
  execsql { INSERT INTO t4 VALUES(1, NULL) }
} {}
do_test fkey2-14.2.2.5 {
  catchsql { UPDATE t4 SET b = 5 }
} {1 {foreign key constraint failed}}
do_test fkey2-14.2.2.6 {
  catchsql { UPDATE t4 SET b = 1 }
} {0 {}}
do_test fkey2-14.2.2.7 {
  execsql { INSERT INTO t3 VALUES(1, NULL, 1) }
} {}

#-------------------------------------------------------------------------
# The following tests, fkey2-15.*, test that unnecessary FK related scans 
# and lookups are avoided when the constraint counters are zero.
#
drop_all_tables
proc execsqlS {zSql} {
  set ::sqlite_search_count 0