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Enhancements to sqlite3ExprImpliesExpr() so that it realizes that

Browse Source 
"iif(A,B)" implies "A".

FossilOrigin-Name: d96ecbee59b50eca25447456dfff2c168e8eade7a68e542932d5829f97debb31
This commit is contained in:
drh
2024-11-28 00:34:20 +00:00
parent 0bce1d6c9f
commit 60ad526639
4 changed files with 83 additions and 29 deletions
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19
manifest
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@@ -1,5 +1,5 @@
C Fix\san\sinaccuracy\sin\sthe\sdocumentation\sin\sfts5.h.
D 2024-11-27T18:01:25.186
C Enhancements\sto\ssqlite3ExprImpliesExpr()\sso\sthat\sit\srealizes\sthat\n"iif(A,B)"\simplies\s"A".
D 2024-11-28T00:34:20.169
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md e108e1e69ae8e8a59e93c455654b8ac9356a11720d3345df2a4743e9590fb20d
@@ -726,7 +726,7 @@ F src/date.c 89ce1ff20512a7fa5070ba6e7dd5c171148ca7d580955795bf97c79c2456144a
F src/dbpage.c db1be8adaf1f839ad733c08baeac5c22aa912f7b535865c0c061382602081360
F src/dbstat.c 73362c0df0f40ad5523a6f5501224959d0976757b511299bf892313e79d14f5c
F src/delete.c 03a77ba20e54f0f42ebd8eddf15411ed6bdb06a2c472ac4b6b336521bf7cea42
F src/expr.c a9d9f5fdfbdd3b2c94d7af1b11f181464b8a641736cf32cb92fa3c5e7ecb30df
F src/expr.c bc1e0266dfd88c996e509550220b74b46c7654b0818909adba8ba8227452cd3e
F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
F src/func.c 49489dcce46d2d491cedb451e974264150c473e5f5bba448498a9aa4c1993537
@@ -860,7 +860,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
F src/wal.c 8b7e309a8012659ac9275ad8cdcc6acaf73fa04b1090e38a01335f230fd10681
F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
F src/walker.c d5006d6b005e4ea7302ad390957a8d41ed83faa177e412f89bc5600a7462a014
F src/where.c 504d72098437ab97dfd3a71cea85e554381650f9dffde277c66603f3e34daddc
F src/where.c b34adb09fdb2a4f57a0bafd4194b501047ef383976fef9f0ac3f395f4881694d
F src/whereInt.h 1e36ec50392f7cc3d93d1152d4338064cd522b87156a0739388b7e273735f0ca
F src/wherecode.c 0c3d3199a2b769a5e2bb70feb5003dc85b3d86842ecaf903a47f2b4205ca5dab
F src/whereexpr.c 0f93a29cabd3a338d09a1f5c6770620a1ac51ec1157f3229502a7e7767c60b6f
@@ -2201,8 +2201,11 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
P 1e405c39a8405e2081ce061559d1aacc70055fc74ab86d886b973076a3fb124b
R 306a37bedf7a72c95bbfd16141af1dca
U dan
Z 0f8994542e0c6b090d32b7bcc99e7877
P ec3ca6f17972a9624018ae352e5a4be8dc34602a4569c80e827e09cd7fbed7f7
R 7e7059a06e37f0bd3101b74065b6331a
T *branch * expr-implies-expr
T *sym-expr-implies-expr *
T -sym-trunk *
U drh
Z 9da80189eab742fa7806914a5f17a037
# Remove this line to create a well-formed Fossil manifest.

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@@ -1 +1 @@
ec3ca6f17972a9624018ae352e5a4be8dc34602a4569c80e827e09cd7fbed7f7
d96ecbee59b50eca25447456dfff2c168e8eade7a68e542932d5829f97debb31

90
src/expr.c
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@@ -6180,16 +6180,20 @@ void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
** same as that currently bound to variable pVar, non-zero is returned.
** Otherwise, if the values are not the same or if pExpr is not a simple
** SQL value, zero is returned.
**
** If the SQLITE_EnableQPSG flag is set on the database connection, then
** this routine always returns false.
*/
static int exprCompareVariable(
static SQLITE_NOINLINE int exprCompareVariable(
const Parse *pParse,
const Expr *pVar,
const Expr *pExpr
){
int res = 0;
int res = 2;
int iVar;
sqlite3_value *pL, *pR = 0;
if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) return 2;
sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB, &pR);
if( pR ){
iVar = pVar->iColumn;
@@ -6199,12 +6203,11 @@ static int exprCompareVariable(
if( sqlite3_value_type(pL)==SQLITE_TEXT ){
sqlite3_value_text(pL); /* Make sure the encoding is UTF-8 */
}
res = 0==sqlite3MemCompare(pL, pR, 0);
res = sqlite3MemCompare(pL, pR, 0) ? 2 : 0;
}
sqlite3ValueFree(pR);
sqlite3ValueFree(pL);
}
return res;
}
@@ -6230,12 +6233,10 @@ static int exprCompareVariable(
** just might result in some slightly slower code. But returning
** an incorrect 0 or 1 could lead to a malfunction.
**
** If pParse is not NULL then TK_VARIABLE terms in pA with bindings in
** pParse->pReprepare can be matched against literals in pB. The
** pParse->pVdbe->expmask bitmask is updated for each variable referenced.
** If pParse is NULL (the normal case) then any TK_VARIABLE term in
** Argument pParse should normally be NULL. If it is not NULL and pA or
** pB causes a return value of 2.
** If pParse is not NULL and SQLITE_EnableQPSG is off then TK_VARIABLE
** terms in pA with bindings in pParse->pReprepare can be matched against
** literals in pB. The pParse->pVdbe->expmask bitmask is updated for
** each variable referenced.
*/
int sqlite3ExprCompare(
const Parse *pParse,
@@ -6247,8 +6248,8 @@ int sqlite3ExprCompare(
if( pA==0 || pB==0 ){
return pB==pA ? 0 : 2;
}
if( pParse && pA->op==TK_VARIABLE && exprCompareVariable(pParse, pA, pB) ){
return 0;
if( pParse && pA->op==TK_VARIABLE ){
return exprCompareVariable(pParse, pA, pB);
}
combinedFlags = pA->flags | pB->flags;
if( combinedFlags & EP_IntValue ){
@@ -6443,18 +6444,66 @@ static int exprImpliesNotNull(
return 0;
}
/*
** Return true if the boolean value of the expression is always either
** FALSE or NULL.
*/
static int sqlite3ExprIsNotTrue(Expr *pExpr){
int v;
if( pExpr->op==TK_NULL ) return 1;
if( pExpr->op==TK_TRUEFALSE && sqlite3ExprTruthValue(pExpr)==0 ) return 1;
v = 1;
if( sqlite3ExprIsInteger(pExpr, &v, 0) && v==0 ) return 1;
return 0;
}
/*
** Return true if the expression is one of the following:
**
** CASE WHEN x THEN y END
** CASE WHEN x THEN y ELSE NULL END
** CASE WHEN x THEN y ELSE false END
** iif(x,y)
** iif(x,y,NULL)
** iif(x,y,false)
*/
static int sqlite3ExprIsIIF(sqlite3 *db, const Expr *pExpr){
ExprList *pList;
if( pExpr->op==TK_FUNCTION ){
const char *z = pExpr->u.zToken;
FuncDef *pDef;
if( (z[0]!='i' && z[0]!='I') ) return 0;
if( pExpr->x.pList==0 ) return 0;
pDef = sqlite3FindFunction(db, z, pExpr->x.pList->nExpr, ENC(db), 0);
if( pDef==0 ) return 0;
if( (pDef->funcFlags & SQLITE_FUNC_INLINE)==0 ) return 0;
if( SQLITE_PTR_TO_INT(pDef->pUserData)!=INLINEFUNC_iif ) return 0;
}else if( pExpr->op==TK_CASE ){
if( pExpr->pLeft!=0 ) return 0;
}else{
return 0;
}
pList = pExpr->x.pList;
assert( pList!=0 );
if( pList->nExpr==2 ) return 1;
if( pList->nExpr==3 && sqlite3ExprIsNotTrue(pList->a[2].pExpr) ) return 1;
return 0;
}
/*
** Return true if we can prove the pE2 will always be true if pE1 is
** true. Return false if we cannot complete the proof or if pE2 might
** be false. Examples:
**
** pE1: x==5 pE2: x==5 Result: true
** pE1: x>0 pE2: x==5 Result: false
** pE1: x=21 pE2: x=21 OR y=43 Result: true
** pE1: x!=123 pE2: x IS NOT NULL Result: true
** pE1: x!=?1 pE2: x IS NOT NULL Result: true
** pE1: x IS NULL pE2: x IS NOT NULL Result: false
** pE1: x IS ?2 pE2: x IS NOT NULL Result: false
** pE1: x==5 pE2: x==5 Result: true
** pE1: x>0 pE2: x==5 Result: false
** pE1: x=21 pE2: x=21 OR y=43 Result: true
** pE1: x!=123 pE2: x IS NOT NULL Result: true
** pE1: x!=?1 pE2: x IS NOT NULL Result: true
** pE1: x IS NULL pE2: x IS NOT NULL Result: false
** pE1: x IS ?2 pE2: x IS NOT NULL Result: false
** pE1: iif(x,y) pE2: x Result: true
** PE1: iif(x,y,0) pE2: x Result: true
**
** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
** Expr.iTable<0 then assume a table number given by iTab.
@@ -6488,6 +6537,9 @@ int sqlite3ExprImpliesExpr(
){
return 1;
}
if( sqlite3ExprIsIIF(pParse->db, pE1) ){
return sqlite3ExprImpliesExpr(pParse,pE1->x.pList->a[0].pExpr,pE2,iTab);
}
return 0;
}

1
src/where.c
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@@ -3564,7 +3564,6 @@ static int whereUsablePartialIndex(
if( !whereUsablePartialIndex(iTab,jointype,pWC,pWhere->pLeft) ) return 0;
pWhere = pWhere->pRight;
}
if( pParse->db->flags & SQLITE_EnableQPSG ) pParse = 0;
for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
Expr *pExpr;
pExpr = pTerm->pExpr;