SQLite

      for(i=0; i<nCol; i++){
        sqlite3VdbeAddOp2(v, OP_Copy, aiCol[i]+1+regData, regTemp+i);
      }
  
      /* If the parent table is the same as the child table, and we are about
      ** to increment the constraint-counter (i.e. this is an INSERT operation),
      ** then check if the row being inserted matches itself. If so, do not
      ** increment the constraint-counter. 
      **
      ** If any of the parent-key values are NULL, then the row cannot match 
      ** itself. So set JUMPIFNULL to make sure we do the OP_Found if any
      ** of the parent-key values are NULL (at this point it is known that
      ** none of the child key values are).
      */
      if( pTab==pFKey->pFrom && nIncr==1 ){
        int iJump = sqlite3VdbeCurrentAddr(v) + nCol + 1;
        for(i=0; i<nCol; i++){
          int iChild = aiCol[i]+1+regData;
          int iParent = pIdx->aiColumn[i]+1+regData;
          assert( aiCol[i]!=pTab->iPKey );
          if( pIdx->aiColumn[i]==pTab->iPKey ){
            /* The parent key is a composite key that includes the IPK column */
            iParent = regData;
          }
          sqlite3VdbeAddOp3(v, OP_Ne, iChild, iJump, iParent);
          sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
        }
        sqlite3VdbeAddOp2(v, OP_Goto, 0, iOk);
      }
  
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regTemp, nCol, regRec);
      sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v,pIdx), P4_TRANSIENT);
      sqlite3VdbeAddOp4Int(v, OP_Found, iCur, iOk, regRec, 0);

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

ifcapable {!foreignkey||!trigger} {
  finish_test
  return
}

set testprefix fkey3

# Create a table and some data to work with.
#
do_test fkey3-1.1 {
  execsql {
    PRAGMA foreign_keys=ON;
    CREATE TABLE t1(x INTEGER PRIMARY KEY);

    INSERT INTO t2 VALUES(100);
    INSERT INTO t2 VALUES(101);
    SELECT 1, x FROM t1;
    SELECT 2, y FROM t2;
  }
} {1 100 1 101 2 100 2 101}


#-------------------------------------------------------------------------
# The following tests - fkey-3.* - test some edge cases to do with 
# inserting rows into tables that have foreign keys where the parent
# table is the same as the child table. Especially cases where the
# new row being inserted matches itself.
#
do_execsql_test 3.1.1 {
  CREATE TABLE t3(a, b, c, d, 
    UNIQUE(a, b),
    FOREIGN KEY(c, d) REFERENCES t3(a, b)
  );
  INSERT INTO t3 VALUES(1, 2, 1, 2);
} {}
do_catchsql_test 3.1.2 {
  INSERT INTO t3 VALUES(NULL, 2, 5, 2);
} {1 {foreign key constraint failed}}
do_catchsql_test 3.1.3 {
  INSERT INTO t3 VALUES(NULL, 3, 5, 2);
} {1 {foreign key constraint failed}}

do_execsql_test 3.2.1 {
  CREATE TABLE t4(a UNIQUE, b REFERENCES t4(a));
}
do_catchsql_test 3.2.2 {
  INSERT INTO t4 VALUES(NULL, 1);
} {1 {foreign key constraint failed}}

do_execsql_test 3.3.1 {
  CREATE TABLE t5(a INTEGER PRIMARY KEY, b REFERENCES t5(a));
  INSERT INTO t5 VALUES(NULL, 1);
} {}
do_catchsql_test 3.3.2 {
  INSERT INTO t5 VALUES(NULL, 3);
} {1 {foreign key constraint failed}}

do_execsql_test 3.4.1 {
  CREATE TABLE t6(a INTEGER PRIMARY KEY, b, c, d,
    FOREIGN KEY(c, d) REFERENCES t6(a, b)
  );
  CREATE UNIQUE INDEX t6i ON t6(b, a);
}
do_execsql_test 3.4.2  { INSERT INTO t6 VALUES(NULL, 'a', 1, 'a'); } {}
do_execsql_test 3.4.3  { INSERT INTO t6 VALUES(2, 'a', 2, 'a');    } {}
do_execsql_test 3.4.4  { INSERT INTO t6 VALUES(NULL, 'a', 1, 'a'); } {}
do_execsql_test 3.4.5  { INSERT INTO t6 VALUES(5, 'a', 2, 'a'); } {}
do_catchsql_test 3.4.6 { 
  INSERT INTO t6 VALUES(NULL, 'a', 65, 'a');    
} {1 {foreign key constraint failed}}

do_execsql_test 3.4.7 {
  INSERT INTO t6 VALUES(100, 'one', 100, 'one');
  DELETE FROM t6 WHERE a = 100;
}
do_execsql_test 3.4.8 {
  INSERT INTO t6 VALUES(100, 'one', 100, 'one');
  UPDATE t6 SET c = 1, d = 'a' WHERE a = 100;
  DELETE FROM t6 WHERE a = 100;
}

do_execsql_test 3.5.1 {
  CREATE TABLE t7(a, b, c, d INTEGER PRIMARY KEY,
    FOREIGN KEY(c, d) REFERENCES t7(a, b)
  );
  CREATE UNIQUE INDEX t7i ON t7(a, b);
}
do_execsql_test 3.5.2  { INSERT INTO t7 VALUES('x', 1, 'x', NULL) } {}
do_execsql_test 3.5.3  { INSERT INTO t7 VALUES('x', 2, 'x', 2) } {}
do_catchsql_test 3.5.4  { 
  INSERT INTO t7 VALUES('x', 450, 'x', NULL);
} {1 {foreign key constraint failed}}
do_catchsql_test 3.5.5  { 
  INSERT INTO t7 VALUES('x', 450, 'x', 451);
} {1 {foreign key constraint failed}}

finish_test