SQLite

      sqlite3VdbeAddOp4Int(v, OP_Found, iCur, iOk, regRec, 0);
  
      sqlite3ReleaseTempReg(pParse, regRec);
      sqlite3ReleaseTempRange(pParse, regTemp, nCol);
    }
  }

  if( !pFKey->isDeferred && !(pParse->db->flags & SQLITE_DeferForeignKeys)
   && !pParse->pToplevel 
   && !pParse->isMultiWrite 
  ){
    /* Special case: If this is an INSERT statement that will insert exactly
    ** one row into the table, raise a constraint immediately instead of
    ** incrementing a counter. This is necessary as the VM code is being
    ** generated for will not open a statement transaction.  */

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

    if( !pFKey->isDeferred && !(db->flags & SQLITE_DeferForeignKeys) 
     && !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;
    }

    sqlite3ResetAllSchemasOfConnection(db);
  }
  sqlite3BtreeLeaveAll(db);

  /* Any deferred constraint violations have now been resolved. */
  db->nDeferredCons = 0;
  db->nDeferredImmCons = 0;
  db->flags &= ~SQLITE_DeferForeignKeys;

  /* If one has been configured, invoke the rollback-hook callback */
  if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
    db->xRollbackCallback(db->pRollbackArg);
  }
}

#endif
    /* The following is VERY experimental */
    { "writable_schema",          SQLITE_WriteSchema|SQLITE_RecoveryMode },

    /* TODO: Maybe it shouldn't be possible to change the ReadUncommitted
    ** flag if there are any active statements. */
    { "read_uncommitted",         SQLITE_ReadUncommitted },
    { "recursive_triggers",       SQLITE_RecTriggers },

    /* This flag may only be set if both foreign-key and trigger support
    ** are present in the build.  */
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
    { "foreign_keys",             SQLITE_ForeignKeys },

#endif
  };
  int i;
  const struct sPragmaType *p;
  for(i=0, p=aPragma; i<ArraySize(aPragma); i++, p++){
    if( sqlite3StrICmp(zLeft, p->zName)==0 ){
      sqlite3 *db = pParse->db;

            mask &= ~(SQLITE_ForeignKeys);
          }

          if( sqlite3GetBoolean(zRight, 0) ){
            db->flags |= mask;
          }else{
            db->flags &= ~mask;

          }

          /* Many of the flag-pragmas modify the code generated by the SQL 
          ** compiler (eg. count_changes). So add an opcode to expire all
          ** compiled SQL statements after modifying a pragma value.
          */
          sqlite3VdbeAddOp2(v, OP_Expire, 0, 0);

          }
          ++i;
          pFK = pFK->pNextFrom;
        }
      }
    }
  }else

  if( sqlite3StrICmp(zLeft, "defer_foreign_keys")==0 ){
    if( zRight ){
      if( sqlite3GetBoolean(zRight, 0) ){
        db->flags |= SQLITE_DeferForeignKeys;
      }else{
        db->flags &= ~SQLITE_DeferForeignKeys;
        db->nDeferredImmCons = 0;
      }
      sqlite3VdbeAddOp2(v, OP_Expire, 0, 0);
    }else{
      int bVal = !!(db->flags & SQLITE_DeferForeignKeys);
      returnSingleInt(pParse, "defer_foreign_keys", bVal);
    }
  }
#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */

#ifndef SQLITE_OMIT_FOREIGN_KEY
#ifndef SQLITE_OMIT_TRIGGER
  if( sqlite3StrICmp(zLeft, "foreign_key_check")==0 ){
    FKey *pFK;             /* A foreign key constraint */
    Table *pTab;           /* Child table contain "REFERENCES" keyword */

#define SQLITE_ReverseOrder   0x00010000  /* Reverse unordered SELECTs */
#define SQLITE_RecTriggers    0x00020000  /* Enable recursive triggers */
#define SQLITE_ForeignKeys    0x00040000  /* Enforce foreign key constraints  */
#define SQLITE_AutoIndex      0x00080000  /* Enable automatic indexes */
#define SQLITE_PreferBuiltin  0x00100000  /* Preference to built-in funcs */
#define SQLITE_LoadExtension  0x00200000  /* Enable load_extension */
#define SQLITE_EnableTrigger  0x00400000  /* True to enable triggers */
#define SQLITE_DeferForeignKeys 0x00800000

/*
** Bits of the sqlite3.dbOptFlags field that are used by the
** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
** selectively disable various optimizations.
*/
#define SQLITE_QueryFlattener 0x0001   /* Query flattening */

**
** Increment a "constraint counter" by P2 (P2 may be negative or positive).
** If P1 is non-zero, the database constraint counter is incremented 
** (deferred foreign key constraints). Otherwise, if P1 is zero, the 
** statement counter is incremented (immediate foreign key constraints).
*/
case OP_FkCounter: {
  if( db->flags & SQLITE_DeferForeignKeys ){
    db->nDeferredImmCons += pOp->p2;
  }else if( pOp->p1 ){
    db->nDeferredCons += pOp->p2;
  }else{
    p->nFkConstraint += pOp->p2;
  }
  break;

          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db, SQLITE_OK);
        }else{
          db->nDeferredCons = 0;
          db->nDeferredImmCons = 0;
          db->flags &= ~SQLITE_DeferForeignKeys;
          sqlite3CommitInternalChanges(db);
        }
      }else{
        sqlite3RollbackAll(db, SQLITE_OK);
      }
      db->nStatement = 0;
    }else if( eStatementOp==0 ){