SQLite

        ** row cannot cause an FK violation. Jump directly to addrOk in 
        ** this case. */
        for(j=0; j<pFK->nCol; j++){
          int iCol = aiCols ? aiCols[j] : pFK->aCol[j].iFrom;
          sqlite3ExprCodeGetColumnOfTable(v, pTab, 0, iCol, regRow+j);
          sqlite3VdbeAddOp2(v, OP_IsNull, regRow+j, addrOk); VdbeCoverage(v);
        }
        if( regRow+j>pParse->nMem ) pParse->nMem = regRow+j;

        /* Generate code to query the parent index for a matching parent
        ** key. If a match is found, jump to addrOk. */
        if( pIdx ){
          sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, pFK->nCol, regKey,
              sqlite3IndexAffinityStr(db,pIdx), pFK->nCol);
          sqlite3VdbeAddOp4Int(v, OP_Found, i, addrOk, regKey, 0);

  INSERT INTO c1 VALUES(1);
} {1 {foreign key mismatch - "c1" referencing "p1"}}

do_execsql_test 6.2 {
  CREATE UNIQUE INDEX p1x2 ON p1(x);
  INSERT INTO c1 VALUES(1);
} {}

# 2021-07-03 https://sqlite.org/forum/forumpost/a6b0c05277
# Failure to allocate enough registers in the VDBE for a
# PRAGMA foreign_key_check when the foreign key has more
# columns than the table.
#
reset_db
do_execsql_test 7.1 {
  PRAGMA foreign_keys=OFF;
  CREATE TABLE t1(a,b,c,FOREIGN KEY(a,a,a,a,a,a,a,a,a,a,a,a,a,a) REFERENCES t0);
  INSERT INTO t1 VALUES(1,2,3);
  PRAGMA foreign_key_check;
} {t1 1 t0 0}


finish_test