SQLite: Check-in [98853f61]

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Overview

Comment:	Generalize the IS and IS NOT operators so that their right-hand side can be an arbitrary expression and not simple the constant NULL. They work like = and <> except that NULL values compare equal to one another an unequal to everything else.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA1:	98853f6104076c50ea92175e17a3254bfbbd4619
User & Date:	drh 2009-09-23 02:29:37

References

2014-10-02
21:25		• New ticket [8c32a33a] Segfault on a syntax error involving the IS operator. (artifact: 7de8fdb3 user: drh)

Context

2009-09-23
03:01		Do not run ON UPDATE actions of a foreign key constraint unless at least one column value really does change. (check-in: 71ac8e28 user: drh tags: trunk)
02:29		Generalize the IS and IS NOT operators so that their right-hand side can be an arbitrary expression and not simple the constant NULL. They work like = and <> except that NULL values compare equal to one another an unequal to everything else. (check-in: 98853f61 user: drh tags: trunk)
2009-09-22
20:08		Factor the UMINUS and UPLUS tokens out of the parser so that the parser tables can go back to using 8-bit values instead of 16-bit values. (check-in: 3fc938c9 user: drh tags: trunk)

Changes

Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to addopcodes.awk.

}
END {
  printf "#define TK_%-29s %4d\n", "TO_TEXT",         ++max
  printf "#define TK_%-29s %4d\n", "TO_BLOB",         ++max
  printf "#define TK_%-29s %4d\n", "TO_NUMERIC",      ++max
  printf "#define TK_%-29s %4d\n", "TO_INT",          ++max
  printf "#define TK_%-29s %4d\n", "TO_REAL",         ++max

  printf "#define TK_%-29s %4d\n", "END_OF_FILE",     ++max
  printf "#define TK_%-29s %4d\n", "ILLEGAL",         ++max
  printf "#define TK_%-29s %4d\n", "SPACE",           ++max
  printf "#define TK_%-29s %4d\n", "UNCLOSED_STRING", ++max
  printf "#define TK_%-29s %4d\n", "FUNCTION",        ++max
  printf "#define TK_%-29s %4d\n", "COLUMN",          ++max
  printf "#define TK_%-29s %4d\n", "AGG_FUNCTION",    ++max
  printf "#define TK_%-29s %4d\n", "AGG_COLUMN",      ++max
  printf "#define TK_%-29s %4d\n", "CONST_FUNC",      ++max
  printf "#define TK_%-29s %4d\n", "UMINUS",          ++max
  printf "#define TK_%-29s %4d\n", "UPLUS",           ++max
}

}
END {
  printf "#define TK_%-29s %4d\n", "TO_TEXT",         ++max
  printf "#define TK_%-29s %4d\n", "TO_BLOB",         ++max
  printf "#define TK_%-29s %4d\n", "TO_NUMERIC",      ++max
  printf "#define TK_%-29s %4d\n", "TO_INT",          ++max
  printf "#define TK_%-29s %4d\n", "TO_REAL",         ++max
  printf "#define TK_%-29s %4d\n", "ISNOT",           ++max
  printf "#define TK_%-29s %4d\n", "END_OF_FILE",     ++max
  printf "#define TK_%-29s %4d\n", "ILLEGAL",         ++max
  printf "#define TK_%-29s %4d\n", "SPACE",           ++max
  printf "#define TK_%-29s %4d\n", "UNCLOSED_STRING", ++max
  printf "#define TK_%-29s %4d\n", "FUNCTION",        ++max
  printf "#define TK_%-29s %4d\n", "COLUMN",          ++max
  printf "#define TK_%-29s %4d\n", "AGG_FUNCTION",    ++max
  printf "#define TK_%-29s %4d\n", "AGG_COLUMN",      ++max
  printf "#define TK_%-29s %4d\n", "CONST_FUNC",      ++max
  printf "#define TK_%-29s %4d\n", "UMINUS",          ++max
  printf "#define TK_%-29s %4d\n", "UPLUS",           ++max
}

Changes to src/expr.c.

** pExpr is a comparison operator.  Return the type affinity that should
** be applied to both operands prior to doing the comparison.
*/
static char comparisonAffinity(Expr *pExpr){
  char aff;
  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
          pExpr->op==TK_NE );
  assert( pExpr->pLeft );
  aff = sqlite3ExprAffinity(pExpr->pLeft);
  if( pExpr->pRight ){
    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
  }else if( ExprHasProperty(pExpr, EP_xIsSelect) ){
    aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
  }else if( !aff ){
................................................................................
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, inReg, SQLITE_STOREP2);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;













    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
    case TK_STAR:
    case TK_MINUS:
    case TK_REM:
................................................................................
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;













    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      testcase( op==TK_ISNULL );
      testcase( op==TK_NOTNULL );
................................................................................
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;













    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      testcase( op==TK_ISNULL );
      testcase( op==TK_NOTNULL );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      sqlite3VdbeAddOp2(v, op, r1, dest);








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** pExpr is a comparison operator.  Return the type affinity that should
** be applied to both operands prior to doing the comparison.
*/
static char comparisonAffinity(Expr *pExpr){
  char aff;
  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
          pExpr->op==TK_NE || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
  assert( pExpr->pLeft );
  aff = sqlite3ExprAffinity(pExpr->pLeft);
  if( pExpr->pRight ){
    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
  }else if( ExprHasProperty(pExpr, EP_xIsSelect) ){
    aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
  }else if( !aff ){
................................................................................
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, inReg, SQLITE_STOREP2);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_IS:
    case TK_ISNOT: {
      testcase( op==TK_IS );
      testcase( op==TK_ISNOT );
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      op = (op==TK_IS) ? TK_EQ : TK_NE;
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, inReg, SQLITE_STOREP2 | SQLITE_NULLEQ);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
    case TK_STAR:
    case TK_MINUS:
    case TK_REM:
................................................................................
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_IS:
    case TK_ISNOT: {
      testcase( op==TK_IS );
      testcase( op==TK_ISNOT );
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      op = (op==TK_IS) ? TK_EQ : TK_NE;
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, SQLITE_NULLEQ);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      testcase( op==TK_ISNULL );
      testcase( op==TK_NOTNULL );
................................................................................
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_IS:
    case TK_ISNOT: {
      testcase( op==TK_IS );
      testcase( op==TK_ISNOT );
      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
                                  pExpr->pRight, &r2, &regFree2);
      op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, SQLITE_NULLEQ);
      testcase( regFree1==0 );
      testcase( regFree2==0 );
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      testcase( op==TK_ISNULL );
      testcase( op==TK_NOTNULL );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      sqlite3VdbeAddOp2(v, op, r1, dest);

Changes to src/parse.y.

    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
    pOut->zStart = pOperand->zStart;
    pOut->zEnd = &pPostOp->z[pPostOp->n];
  }                           
}

expr(A) ::= expr(X) ISNULL|NOTNULL(E).   {spanUnaryPostfix(&A,pParse,@E,&X,&E);}
expr(A) ::= expr(X) IS NULL(E).   {spanUnaryPostfix(&A,pParse,TK_ISNULL,&X,&E);}
expr(A) ::= expr(X) NOT NULL(E). {spanUnaryPostfix(&A,pParse,TK_NOTNULL,&X,&E);}













expr(A) ::= expr(X) IS NOT NULL(E).
                                 {spanUnaryPostfix(&A,pParse,TK_NOTNULL,&X,&E);}






%include {
  /* Construct an expression node for a unary prefix operator
  */
  static void spanUnaryPrefix(
    ExprSpan *pOut,        /* Write the new expression node here */
    Parse *pParse,         /* Parsing context to record errors */








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    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
    pOut->zStart = pOperand->zStart;
    pOut->zEnd = &pPostOp->z[pPostOp->n];
  }                           
}

expr(A) ::= expr(X) ISNULL|NOTNULL(E).   {spanUnaryPostfix(&A,pParse,@E,&X,&E);}

expr(A) ::= expr(X) NOT NULL(E). {spanUnaryPostfix(&A,pParse,TK_NOTNULL,&X,&E);}

//    expr1 IS expr2
//    expr1 IS NOT expr2
//
// If expr2 is NULL then code as TK_ISNULL or TK_NOTNULL.  If expr2
// is any other expression, code as TK_IS or TK_ISNOT.
// 
expr(A) ::= expr(X) IS expr(Y).     {
  spanBinaryExpr(&A,pParse,TK_IS,&X,&Y);
  if( pParse->db->mallocFailed==0  && Y.pExpr->op==TK_NULL ){
    A.pExpr->op = TK_ISNULL;
  }
}
expr(A) ::= expr(X) IS NOT expr(Y). {

  spanBinaryExpr(&A,pParse,TK_ISNOT,&X,&Y);
  if( pParse->db->mallocFailed==0  && Y.pExpr->op==TK_NULL ){
    A.pExpr->op = TK_NOTNULL;
  }
}

%include {
  /* Construct an expression node for a unary prefix operator
  */
  static void spanUnaryPrefix(
    ExprSpan *pOut,        /* Write the new expression node here */
    Parse *pParse,         /* Parsing context to record errors */

Changes to src/sqliteInt.h.


/*
** Additional bit values that can be ORed with an affinity without
** changing the affinity.
*/
#define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */
#define SQLITE_STOREP2      0x10  /* Store result in reg[P2] rather than jump */


/*
** An object of this type is created for each virtual table present in
** the database schema. 
**
** If the database schema is shared, then there is one instance of this
** structure for each database connection (sqlite3*) that uses the shared


/*
** Additional bit values that can be ORed with an affinity without
** changing the affinity.
*/
#define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */
#define SQLITE_STOREP2      0x10  /* Store result in reg[P2] rather than jump */
#define SQLITE_NULLEQ       0x80  /* NULL=NULL */

/*
** An object of this type is created for each virtual table present in
** the database schema. 
**
** If the database schema is shared, then there is one instance of this
** structure for each database connection (sqlite3*) that uses the shared

Changes to src/vdbe.c.

** store a boolean result (either 0, or 1, or NULL) in register P2.
*/
/* Opcode: Ne P1 P2 P3 P4 P5
**
** This works just like the Lt opcode except that the jump is taken if
** the operands in registers P1 and P3 are not equal.  See the Lt opcode for
** additional information.






*/
/* Opcode: Eq P1 P2 P3 P4 P5
**
** This works just like the Lt opcode except that the jump is taken if
** the operands in registers P1 and P3 are equal.
** See the Lt opcode for additional information.






*/
/* Opcode: Le P1 P2 P3 P4 P5
**
** This works just like the Lt opcode except that the jump is taken if
** the content of register P3 is less than or equal to the content of
** register P1.  See the Lt opcode for additional information.
*/
................................................................................
*/
case OP_Eq:               /* same as TK_EQ, jump, in1, in3 */
case OP_Ne:               /* same as TK_NE, jump, in1, in3 */
case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
case OP_Le:               /* same as TK_LE, jump, in1, in3 */
case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
  int flags;
  int res;
  char affinity;

  flags = pIn1->flags|pIn3->flags;

  if( flags&MEM_Null ){










    /* If either operand is NULL then the result is always NULL.
    ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
    */
    if( pOp->p5 & SQLITE_STOREP2 ){
      pOut = &p->aMem[pOp->p2];
      MemSetTypeFlag(pOut, MEM_Null);
      REGISTER_TRACE(pOp->p2, pOut);
    }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
      pc = pOp->p2-1;
    }
    break;
  }



  affinity = pOp->p5 & SQLITE_AFF_MASK;
  if( affinity ){
    applyAffinity(pIn1, affinity, encoding);
    applyAffinity(pIn3, affinity, encoding);
    if( db->mallocFailed ) goto no_mem;
  }

  assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
  ExpandBlob(pIn1);
  ExpandBlob(pIn3);
  res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);

  switch( pOp->opcode ){
    case OP_Eq:    res = res==0;     break;
    case OP_Ne:    res = res!=0;     break;
    case OP_Lt:    res = res<0;      break;
    case OP_Le:    res = res<=0;     break;
    case OP_Gt:    res = res>0;      break;
    default:       res = res>=0;     break;
................................................................................
  int bRev;          /* True for DESCENDING sort order */

  n = pOp->p3;
  pKeyInfo = pOp->p4.pKeyInfo;
  assert( n>0 );
  assert( pKeyInfo!=0 );
  p1 = pOp->p1;
  assert( p1>0 && p1+n<=p->nMem+1 );
  p2 = pOp->p2;








  assert( p2>0 && p2+n<=p->nMem+1 );


  for(i=0; i<n; i++){
    idx = aPermute ? aPermute[i] : i;
    REGISTER_TRACE(p1+idx, &p->aMem[p1+idx]);
    REGISTER_TRACE(p2+idx, &p->aMem[p2+idx]);
    assert( i<pKeyInfo->nField );
    pColl = pKeyInfo->aColl[i];
    bRev = pKeyInfo->aSortOrder[i];








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** store a boolean result (either 0, or 1, or NULL) in register P2.
*/
/* Opcode: Ne P1 P2 P3 P4 P5
**
** This works just like the Lt opcode except that the jump is taken if
** the operands in registers P1 and P3 are not equal.  See the Lt opcode for
** additional information.
**
** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
** true or false and is never NULL.  If both operands are NULL then the result
** of comparison is false.  If either operand is NULL then the result is true.
** If neither operand is NULL the the result is the same as it would be if
** the SQLITE_NULLEQ flag were omitted from P5.
*/
/* Opcode: Eq P1 P2 P3 P4 P5
**
** This works just like the Lt opcode except that the jump is taken if
** the operands in registers P1 and P3 are equal.
** See the Lt opcode for additional information.
**
** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
** true or false and is never NULL.  If both operands are NULL then the result
** of comparison is true.  If either operand is NULL then the result is false.
** If neither operand is NULL the the result is the same as it would be if
** the SQLITE_NULLEQ flag were omitted from P5.
*/
/* Opcode: Le P1 P2 P3 P4 P5
**
** This works just like the Lt opcode except that the jump is taken if
** the content of register P3 is less than or equal to the content of
** register P1.  See the Lt opcode for additional information.
*/
................................................................................
*/
case OP_Eq:               /* same as TK_EQ, jump, in1, in3 */
case OP_Ne:               /* same as TK_NE, jump, in1, in3 */
case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
case OP_Le:               /* same as TK_LE, jump, in1, in3 */
case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
  int res;            /* Result of the comparison of pIn1 against pIn3 */

  char affinity;      /* Affinity to use for comparison */



  if( (pIn1->flags | pIn3->flags)&MEM_Null ){
    /* One or both operands are NULL */
    if( pOp->p5 & SQLITE_NULLEQ ){
      /* If SQLITE_NULLEQ is set (which will only happen if the operator is
      ** OP_Eq or OP_Ne) then take the jump or not depending on whether
      ** or not both operands are null.
      */
      assert( pOp->opcode==OP_Eq || pOp->opcode==OP_Ne );
      res = (pIn1->flags & pIn3->flags & MEM_Null)==0;
    }else{
      /* SQLITE_NULLEQ is clear and at least one operand is NULL,
      ** then the result is always NULL.
      ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
      */
      if( pOp->p5 & SQLITE_STOREP2 ){
        pOut = &p->aMem[pOp->p2];
        MemSetTypeFlag(pOut, MEM_Null);
        REGISTER_TRACE(pOp->p2, pOut);
      }else if( pOp->p5 & SQLITE_JUMPIFNULL ){
        pc = pOp->p2-1;
      }
      break;
    }

  }else{
    /* Neither operand is NULL.  Do a comparison. */
    affinity = pOp->p5 & SQLITE_AFF_MASK;
    if( affinity ){
      applyAffinity(pIn1, affinity, encoding);
      applyAffinity(pIn3, affinity, encoding);
      if( db->mallocFailed ) goto no_mem;
    }

    assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
    ExpandBlob(pIn1);
    ExpandBlob(pIn3);
    res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
  }
  switch( pOp->opcode ){
    case OP_Eq:    res = res==0;     break;
    case OP_Ne:    res = res!=0;     break;
    case OP_Lt:    res = res<0;      break;
    case OP_Le:    res = res<=0;     break;
    case OP_Gt:    res = res>0;      break;
    default:       res = res>=0;     break;
................................................................................
  int bRev;          /* True for DESCENDING sort order */

  n = pOp->p3;
  pKeyInfo = pOp->p4.pKeyInfo;
  assert( n>0 );
  assert( pKeyInfo!=0 );
  p1 = pOp->p1;

  p2 = pOp->p2;
#if SQLITE_DEBUG
  if( aPermute ){
    int k, mx = 0;
    for(k=0; k<n; k++) if( aPermute[k]>mx ) mx = aPermute[k];
    assert( p1>0 && p1+mx<=p->nMem+1 );
    assert( p2>0 && p2+mx<=p->nMem+1 );
  }else{
    assert( p1>0 && p1+n<=p->nMem+1 );
    assert( p2>0 && p2+n<=p->nMem+1 );
  }
#endif /* SQLITE_DEBUG */
  for(i=0; i<n; i++){
    idx = aPermute ? aPermute[i] : i;
    REGISTER_TRACE(p1+idx, &p->aMem[p1+idx]);
    REGISTER_TRACE(p2+idx, &p->aMem[p2+idx]);
    assert( i<pKeyInfo->nField );
    pColl = pKeyInfo->aColl[i];
    bRev = pKeyInfo->aSortOrder[i];