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Add support for common table expressions (WITH clauses).

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FossilOrigin-Name: 0171e3bb4f663a9414b0e8b64c87b5d0683855b5
This commit is contained in:
dan
2014-01-17 15:15:10 +00:00
parent 6ade453cd8 b290f11775
commit 718569443d
21 changed files with 1063 additions and 68 deletions
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6
src/btree.c
View File

@@ -7350,6 +7350,7 @@ static int clearDatabasePage(
int rc;
unsigned char *pCell;
int i;
int hdr;
assert( sqlite3_mutex_held(pBt->mutex) );
if( pgno>btreePagecount(pBt) ){
@@ -7358,6 +7359,7 @@ static int clearDatabasePage(
rc = getAndInitPage(pBt, pgno, &pPage, 0);
if( rc ) return rc;
hdr = pPage->hdrOffset;
for(i=0; i<pPage->nCell; i++){
pCell = findCell(pPage, i);
if( !pPage->leaf ){
@@ -7368,7 +7370,7 @@ static int clearDatabasePage(
if( rc ) goto cleardatabasepage_out;
}
if( !pPage->leaf ){
rc = clearDatabasePage(pBt, get4byte(&pPage->aData[8]), 1, pnChange);
rc = clearDatabasePage(pBt, get4byte(&pPage->aData[hdr+8]), 1, pnChange);
if( rc ) goto cleardatabasepage_out;
}else if( pnChange ){
assert( pPage->intKey );
@@ -7377,7 +7379,7 @@ static int clearDatabasePage(
if( freePageFlag ){
freePage(pPage, &rc);
}else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
zeroPage(pPage, pPage->aData[0] | PTF_LEAF);
zeroPage(pPage, pPage->aData[hdr] | PTF_LEAF);
}
cleardatabasepage_out:

70
src/build.c
View File

@@ -4198,3 +4198,73 @@ KeyInfo *sqlite3KeyInfoOfIndex(Parse *pParse, Index *pIdx){
}
return sqlite3KeyInfoRef(pIdx->pKeyInfo);
}
#ifndef SQLITE_OMIT_CTE
/*
** This routine is invoked once per CTE by the parser while parsing a
** WITH clause.
*/
With *sqlite3WithAdd(
Parse *pParse, /* Parsing context */
With *pWith, /* Existing WITH clause, or NULL */
Token *pName, /* Name of the common-table */
ExprList *pArglist, /* Optional column name list for the table */
Select *pQuery /* Query used to initialize the table */
){
sqlite3 *db = pParse->db;
With *pNew;
char *zName;
/* Check that the CTE name is unique within this WITH clause. If
** not, store an error in the Parse structure. */
zName = sqlite3NameFromToken(pParse->db, pName);
if( zName && pWith ){
int i;
for(i=0; i<pWith->nCte; i++){
if( sqlite3StrICmp(zName, pWith->a[i].zName)==0 ){
sqlite3ErrorMsg(pParse, "duplicate WITH table name: %s", zName);
}
}
}
if( pWith ){
int nByte = sizeof(*pWith) + (sizeof(pWith->a[1]) * pWith->nCte);
pNew = sqlite3DbRealloc(db, pWith, nByte);
}else{
pNew = sqlite3DbMallocZero(db, sizeof(*pWith));
}
assert( zName!=0 || pNew==0 );
assert( db->mallocFailed==0 || pNew==0 );
if( pNew==0 ){
sqlite3ExprListDelete(db, pArglist);
sqlite3SelectDelete(db, pQuery);
sqlite3DbFree(db, zName);
pNew = pWith;
}else{
pNew->a[pNew->nCte].pSelect = pQuery;
pNew->a[pNew->nCte].pCols = pArglist;
pNew->a[pNew->nCte].zName = zName;
pNew->a[pNew->nCte].zErr = 0;
pNew->nCte++;
}
return pNew;
}
/*
** Free the contents of the With object passed as the second argument.
*/
void sqlite3WithDelete(sqlite3 *db, With *pWith){
if( pWith ){
int i;
for(i=0; i<pWith->nCte; i++){
struct Cte *pCte = &pWith->a[i];
sqlite3ExprListDelete(db, pCte->pCols);
sqlite3SelectDelete(db, pCte->pSelect);
sqlite3DbFree(db, pCte->zName);
}
sqlite3DbFree(db, pWith);
}
}
#endif /* !defined(SQLITE_OMIT_CTE) */

37
src/expr.c
View File

@@ -895,6 +895,33 @@ static Expr *exprDup(sqlite3 *db, Expr *p, int flags, u8 **pzBuffer){
return pNew;
}
/*
** Create and return a deep copy of the object passed as the second
** argument. If an OOM condition is encountered, NULL is returned
** and the db->mallocFailed flag set.
*/
#ifndef SQLITE_OMIT_CTE
static With *withDup(sqlite3 *db, With *p){
With *pRet = 0;
if( p ){
int nByte = sizeof(*p) + sizeof(p->a[0]) * (p->nCte-1);
pRet = sqlite3DbMallocZero(db, nByte);
if( pRet ){
int i;
pRet->nCte = p->nCte;
for(i=0; i<p->nCte; i++){
pRet->a[i].pSelect = sqlite3SelectDup(db, p->a[i].pSelect, 0);
pRet->a[i].pCols = sqlite3ExprListDup(db, p->a[i].pCols, 0);
pRet->a[i].zName = sqlite3DbStrDup(db, p->a[i].zName);
}
}
}
return pRet;
}
#else
# define withDup(x,y) 0
#endif
/*
** The following group of routines make deep copies of expressions,
** expression lists, ID lists, and select statements. The copies can
@@ -975,6 +1002,7 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p, int flags){
pNewItem->regReturn = pOldItem->regReturn;
pNewItem->isCorrelated = pOldItem->isCorrelated;
pNewItem->viaCoroutine = pOldItem->viaCoroutine;
pNewItem->isRecursive = pOldItem->isRecursive;
pNewItem->zIndex = sqlite3DbStrDup(db, pOldItem->zIndex);
pNewItem->notIndexed = pOldItem->notIndexed;
pNewItem->pIndex = pOldItem->pIndex;
@@ -1036,6 +1064,7 @@ Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
pNew->addrOpenEphm[0] = -1;
pNew->addrOpenEphm[1] = -1;
pNew->addrOpenEphm[2] = -1;
pNew->pWith = withDup(db, p->pWith);
return pNew;
}
#else
@@ -1555,9 +1584,11 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
iCol = (i16)pExpr->iColumn;
/* Code an OP_VerifyCookie and OP_TableLock for <table>. */
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3CodeVerifySchema(pParse, iDb);
sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
if( pTab->pSchema ){
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
sqlite3CodeVerifySchema(pParse, iDb);
sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
}
/* This function is only called from two places. In both cases the vdbe
** has already been allocated. So assume sqlite3GetVdbe() is always

3
src/insert.c
View File

@@ -667,7 +667,8 @@ void sqlite3Insert(
**
** This is the 2nd template.
*/
if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
if( pColumn==0 && pParse->pWith==0
&& xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
assert( !pTrigger );
assert( pList==0 );
goto insert_end;

72
src/parse.y
View File

@@ -204,8 +204,8 @@ columnid(A) ::= nm(X). {
ABORT ACTION AFTER ANALYZE ASC ATTACH BEFORE BEGIN BY CASCADE CAST COLUMNKW
CONFLICT DATABASE DEFERRED DESC DETACH EACH END EXCLUSIVE EXPLAIN FAIL FOR
IGNORE IMMEDIATE INITIALLY INSTEAD LIKE_KW MATCH NO PLAN
QUERY KEY OF OFFSET PRAGMA RAISE RELEASE REPLACE RESTRICT ROW ROLLBACK
SAVEPOINT TEMP TRIGGER VACUUM VIEW VIRTUAL WITHOUT
QUERY KEY OF OFFSET PRAGMA RAISE RECURSIVE RELEASE REPLACE RESTRICT ROW
ROLLBACK SAVEPOINT TEMP TRIGGER VACUUM VIEW VIRTUAL WITH WITHOUT
%ifdef SQLITE_OMIT_COMPOUND_SELECT
EXCEPT INTERSECT UNION
%endif SQLITE_OMIT_COMPOUND_SELECT
@@ -407,12 +407,23 @@ cmd ::= select(X). {
%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type selectnowith {Select*}
%destructor selectnowith {sqlite3SelectDelete(pParse->db, $$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete(pParse->db, $$);}
select(A) ::= oneselect(X). {A = X;}
select(A) ::= with(W) selectnowith(X). {
if( X ){
X->pWith = W;
}else{
sqlite3WithDelete(pParse->db, W);
}
A = X;
}
selectnowith(A) ::= oneselect(X). {A = X;}
%ifndef SQLITE_OMIT_COMPOUND_SELECT
select(A) ::= select(X) multiselect_op(Y) oneselect(Z). {
selectnowith(A) ::= selectnowith(X) multiselect_op(Y) oneselect(Z). {
if( Z ){
Z->op = (u8)Y;
Z->pPrior = X;
@@ -648,15 +659,17 @@ limit_opt(A) ::= LIMIT expr(X) COMMA expr(Y).
/////////////////////////// The DELETE statement /////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= DELETE FROM fullname(X) indexed_opt(I) where_opt(W)
cmd ::= with(C) DELETE FROM fullname(X) indexed_opt(I) where_opt(W)
orderby_opt(O) limit_opt(L). {
sqlite3WithPush(pParse, C, 1);
sqlite3SrcListIndexedBy(pParse, X, &I);
W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "DELETE");
sqlite3DeleteFrom(pParse,X,W);
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= DELETE FROM fullname(X) indexed_opt(I) where_opt(W). {
cmd ::= with(C) DELETE FROM fullname(X) indexed_opt(I) where_opt(W). {
sqlite3WithPush(pParse, C, 1);
sqlite3SrcListIndexedBy(pParse, X, &I);
sqlite3DeleteFrom(pParse,X,W);
}
@@ -671,8 +684,9 @@ where_opt(A) ::= WHERE expr(X). {A = X.pExpr;}
////////////////////////// The UPDATE command ////////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y) where_opt(W)
orderby_opt(O) limit_opt(L). {
cmd ::= with(C) UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
where_opt(W) orderby_opt(O) limit_opt(L). {
sqlite3WithPush(pParse, C, 1);
sqlite3SrcListIndexedBy(pParse, X, &I);
sqlite3ExprListCheckLength(pParse,Y,"set list");
W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "UPDATE");
@@ -680,8 +694,9 @@ cmd ::= UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y) where_opt(W)
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
cmd ::= with(C) UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
where_opt(W). {
sqlite3WithPush(pParse, C, 1);
sqlite3SrcListIndexedBy(pParse, X, &I);
sqlite3ExprListCheckLength(pParse,Y,"set list");
sqlite3Update(pParse,X,Y,W,R);
@@ -702,10 +717,15 @@ setlist(A) ::= nm(X) EQ expr(Y). {
////////////////////////// The INSERT command /////////////////////////////////
//
cmd ::= insert_cmd(R) INTO fullname(X) inscollist_opt(F) select(S).
{sqlite3Insert(pParse, X, S, F, R);}
cmd ::= insert_cmd(R) INTO fullname(X) inscollist_opt(F) DEFAULT VALUES.
{sqlite3Insert(pParse, X, 0, F, R);}
cmd ::= with(W) insert_cmd(R) INTO fullname(X) inscollist_opt(F) select(S). {
sqlite3WithPush(pParse, W, 1);
sqlite3Insert(pParse, X, S, F, R);
}
cmd ::= with(W) insert_cmd(R) INTO fullname(X) inscollist_opt(F) DEFAULT VALUES.
{
sqlite3WithPush(pParse, W, 1);
sqlite3Insert(pParse, X, 0, F, R);
}
%type insert_cmd {u8}
insert_cmd(A) ::= INSERT orconf(R). {A = R;}
@@ -851,10 +871,8 @@ expr(A) ::= expr(X) STAR|SLASH|REM(OP) expr(Y).
{spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) CONCAT(OP) expr(Y). {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
%type likeop {struct LikeOp}
likeop(A) ::= LIKE_KW(X). {A.eOperator = X; A.bNot = 0;}
likeop(A) ::= NOT LIKE_KW(X). {A.eOperator = X; A.bNot = 1;}
likeop(A) ::= MATCH(X). {A.eOperator = X; A.bNot = 0;}
likeop(A) ::= NOT MATCH(X). {A.eOperator = X; A.bNot = 1;}
likeop(A) ::= LIKE_KW|MATCH(X). {A.eOperator = X; A.bNot = 0;}
likeop(A) ::= NOT LIKE_KW|MATCH(X). {A.eOperator = X; A.bNot = 1;}
expr(A) ::= expr(X) likeop(OP) expr(Y). [LIKE_KW] {
ExprList *pList;
pList = sqlite3ExprListAppend(pParse,0, Y.pExpr);
@@ -1364,3 +1382,23 @@ anylist ::= .
anylist ::= anylist LP anylist RP.
anylist ::= anylist ANY.
%endif SQLITE_OMIT_VIRTUALTABLE
//////////////////////// COMMON TABLE EXPRESSIONS ////////////////////////////
%type with {With*}
%type wqlist {With*}
%destructor with {sqlite3WithDelete(pParse->db, $$);}
%destructor wqlist {sqlite3WithDelete(pParse->db, $$);}
with(A) ::= . {A = 0;}
%ifndef SQLITE_OMIT_CTE
with(A) ::= WITH wqlist(W). { A = W; }
with(A) ::= WITH RECURSIVE wqlist(W). { A = W; }
wqlist(A) ::= nm(X) idxlist_opt(Y) AS LP select(Z) RP. {
A = sqlite3WithAdd(pParse, 0, &X, Y, Z);
}
wqlist(A) ::= wqlist(W) COMMA nm(X) idxlist_opt(Y) AS LP select(Z) RP. {
A = sqlite3WithAdd(pParse, W, &X, Y, Z);
}
%endif SQLITE_OMIT_CTE

311
src/select.c
View File

@@ -29,6 +29,7 @@ static void clearSelect(sqlite3 *db, Select *p){
sqlite3SelectDelete(db, p->pPrior);
sqlite3ExprDelete(db, p->pLimit);
sqlite3ExprDelete(db, p->pOffset);
sqlite3WithDelete(db, p->pWith);
}
/*
@@ -690,12 +691,26 @@ static void selectInnerLoop(
/* Store the result as data using a unique key.
*/
case SRT_DistTable:
case SRT_Table:
case SRT_EphemTab: {
int r1 = sqlite3GetTempReg(pParse);
testcase( eDest==SRT_Table );
testcase( eDest==SRT_EphemTab );
sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
#ifndef SQLITE_OMIT_CTE
if( eDest==SRT_DistTable ){
/* If the destination is DistTable, then cursor (iParm+1) is open
** on an ephemeral index. If the current row is already present
** in the index, do not write it to the output. If not, add the
** current row to the index and proceed with writing it to the
** output table as well. */
int addr = sqlite3VdbeCurrentAddr(v) + 4;
sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r1);
assert( pOrderBy==0 );
}
#endif
if( pOrderBy ){
pushOntoSorter(pParse, pOrderBy, p, r1);
}else{
@@ -1202,7 +1217,7 @@ static const char *columnTypeImpl(
sNC.pParse = pNC->pParse;
zType = columnType(&sNC, p,&zOrigDb,&zOrigTab,&zOrigCol, &estWidth);
}
}else if( ALWAYS(pTab->pSchema) ){
}else if( pTab->pSchema ){
/* A real table */
assert( !pS );
if( iCol<0 ) iCol = pTab->iPKey;
@@ -1729,6 +1744,7 @@ static int multiSelect(
** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
*/
assert( p && p->pPrior ); /* Calling function guarantees this much */
assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
db = pParse->db;
pPrior = p->pPrior;
assert( pPrior->pRightmost!=pPrior );
@@ -1774,11 +1790,91 @@ static int multiSelect(
goto multi_select_end;
}
#ifndef SQLITE_OMIT_CTE
if( p->selFlags & SF_Recursive ){
SrcList *pSrc = p->pSrc;
int nCol = p->pEList->nExpr;
int addrNext;
int addrSwap;
int iCont, iBreak;
int tmp1; /* Intermediate table */
int tmp2; /* Next intermediate table */
int tmp3 = 0; /* To ensure unique results if UNION */
int eDest = SRT_Table;
SelectDest tmp2dest;
int i;
/* Check that there is no ORDER BY or LIMIT clause. Neither of these
** are supported on recursive queries. */
assert( p->pOffset==0 || p->pLimit );
if( p->pOrderBy || p->pLimit ){
sqlite3ErrorMsg(pParse, "%s in a recursive query is not allowed",
p->pOrderBy ? "ORDER BY" : "LIMIT"
);
goto multi_select_end;
}
if( sqlite3AuthCheck(pParse, SQLITE_RECURSIVE, 0, 0, 0) ){
goto multi_select_end;
}
iBreak = sqlite3VdbeMakeLabel(v);
iCont = sqlite3VdbeMakeLabel(v);
for(i=0; ALWAYS(i<pSrc->nSrc); i++){
if( pSrc->a[i].isRecursive ){
tmp1 = pSrc->a[i].iCursor;
break;
}
}
tmp2 = pParse->nTab++;
if( p->op==TK_UNION ){
eDest = SRT_DistTable;
tmp3 = pParse->nTab++;
}
sqlite3SelectDestInit(&tmp2dest, eDest, tmp2);
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tmp1, nCol);
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tmp2, nCol);
if( tmp3 ){
p->addrOpenEphm[0] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tmp3, 0);
p->selFlags |= SF_UsesEphemeral;
}
/* Store the results of the initial SELECT in tmp2. */
rc = sqlite3Select(pParse, pPrior, &tmp2dest);
if( rc ) goto multi_select_end;
/* Clear tmp1. Then switch the contents of tmp1 and tmp2. Then return
** the contents of tmp1 to the caller. Or, if tmp1 is empty at this
** point, the recursive query has finished - jump to address iBreak. */
addrSwap = sqlite3VdbeAddOp2(v, OP_SwapCursors, tmp1, tmp2);
sqlite3VdbeAddOp2(v, OP_Rewind, tmp1, iBreak);
addrNext = sqlite3VdbeCurrentAddr(v);
selectInnerLoop(pParse, p, p->pEList, tmp1, p->pEList->nExpr,
0, 0, &dest, iCont, iBreak);
sqlite3VdbeResolveLabel(v, iCont);
sqlite3VdbeAddOp2(v, OP_Next, tmp1, addrNext);
/* Execute the recursive SELECT. Store the results in tmp2. While this
** SELECT is running, the contents of tmp1 are read by recursive
** references to the current CTE. */
p->pPrior = 0;
rc = sqlite3Select(pParse, p, &tmp2dest);
assert( p->pPrior==0 );
p->pPrior = pPrior;
if( rc ) goto multi_select_end;
sqlite3VdbeAddOp2(v, OP_Goto, 0, addrSwap);
sqlite3VdbeResolveLabel(v, iBreak);
}else
#endif
/* Compound SELECTs that have an ORDER BY clause are handled separately.
*/
if( p->pOrderBy ){
return multiSelectOrderBy(pParse, p, pDest);
}
}else
/* Generate code for the left and right SELECT statements.
*/
@@ -2842,6 +2938,14 @@ static void substSelect(
** (21) The subquery does not use LIMIT or the outer query is not
** DISTINCT. (See ticket [752e1646fc]).
**
** (22) The subquery is not a recursive CTE.
**
** (23) The parent is not a recursive CTE, or the sub-query is not a
** compound query. This restriction is because transforming the
** parent to a compound query confuses the code that handles
** recursive queries in multiSelect().
**
**
** In this routine, the "p" parameter is a pointer to the outer query.
** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
@@ -2913,6 +3017,8 @@ static int flattenSubquery(
if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
return 0; /* Restriction (21) */
}
if( pSub->selFlags & SF_Recursive ) return 0; /* Restriction (22) */
if( (p->selFlags & SF_Recursive) && pSub->pPrior ) return 0; /* (23) */
/* OBSOLETE COMMENT 1:
** Restriction 3: If the subquery is a join, make sure the subquery is
@@ -3394,6 +3500,183 @@ static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
return WRC_Continue;
}
#ifndef SQLITE_OMIT_CTE
/*
** Argument pWith (which may be NULL) points to a linked list of nested
** WITH contexts, from inner to outermost. If the table identified by
** FROM clause element pItem is really a common-table-expression (CTE)
** then return a pointer to the CTE definition for that table. Otherwise
** return NULL.
*/
static struct Cte *searchWith(With *pWith, struct SrcList_item *pItem){
const char *zName;
if( pItem->zDatabase==0 && (zName = pItem->zName)!=0 ){
With *p;
for(p=pWith; p; p=p->pOuter){
int i;
for(i=0; i<p->nCte; i++){
if( sqlite3StrICmp(zName, p->a[i].zName)==0 ){
return &p->a[i];
}
}
}
}
return 0;
}
/* The code generator maintains a stack of active WITH clauses
** with the inner-most WITH clause being at the top of the stack.
**
** This routine pushes the WITH clause passed as the second argument
** onto the top of the stack. If argument bFree is true, then this
** WITH clause will never be popped from the stack. In this case it
** should be freed along with the Parse object. In other cases, when
** bFree==0, the With object will be freed along with the SELECT
** statement with which it is associated.
*/
void sqlite3WithPush(Parse *pParse, With *pWith, u8 bFree){
assert( bFree==0 || pParse->pWith==0 );
if( pWith ){
pWith->pOuter = pParse->pWith;
pParse->pWith = pWith;
pParse->bFreeWith = bFree;
}
}
/*
** This function checks if argument pFrom refers to a CTE declared by
** a WITH clause on the stack currently maintained by the parser. And,
** if currently processing a CTE expression, if it is a recursive
** reference to the current CTE.
**
** If pFrom falls into either of the two categories above, pFrom->pTab
** and other fields are populated accordingly. The caller should check
** (pFrom->pTab!=0) to determine whether or not a successful match
** was found.
**
** Whether or not a match is found, SQLITE_OK is returned if no error
** occurs. If an error does occur, an error message is stored in the
** parser and some error code other than SQLITE_OK returned.
*/
static int withExpand(
Walker *pWalker,
struct SrcList_item *pFrom
){
Table *pTab;
Parse *pParse = pWalker->pParse;
sqlite3 *db = pParse->db;
struct Cte *pCte;
assert( pFrom->pTab==0 );
pCte = searchWith(pParse->pWith, pFrom);
if( pCte ){
ExprList *pEList;
Select *pSel;
Select *pLeft; /* Left-most SELECT statement */
int bMayRecursive; /* True if compound joined by UNION [ALL] */
/* If pCte->zErr is non-NULL at this point, then this is an illegal
** recursive reference to CTE pCte. Leave an error in pParse and return
** early. If pCte->zErr is NULL, then this is not a recursive reference.
** In this case, proceed. */
if( pCte->zErr ){
sqlite3ErrorMsg(pParse, pCte->zErr, pCte->zName);
return WRC_Abort;
}
pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
if( pTab==0 ) return WRC_Abort;
pTab->nRef = 1;
pTab->zName = sqlite3DbStrDup(db, pCte->zName);
pTab->iPKey = -1;
pTab->nRowEst = 1048576;
pTab->tabFlags |= TF_Ephemeral;
pFrom->pSelect = sqlite3SelectDup(db, pCte->pSelect, 0);
if( db->mallocFailed ) return SQLITE_NOMEM;
assert( pFrom->pSelect );
/* Check if this is a recursive CTE. */
pSel = pFrom->pSelect;
bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION );
if( bMayRecursive ){
int i;
SrcList *pSrc = pFrom->pSelect->pSrc;
for(i=0; i<pSrc->nSrc; i++){
struct SrcList_item *pItem = &pSrc->a[i];
if( pItem->zDatabase==0
&& pItem->zName!=0
&& 0==sqlite3StrICmp(pItem->zName, pCte->zName)
){
pItem->pTab = pTab;
pItem->isRecursive = 1;
pTab->nRef++;
pSel->selFlags |= SF_Recursive;
}
}
}
/* Only one recursive reference is permitted. */
if( pTab->nRef>2 ){
sqlite3ErrorMsg(
pParse, "multiple references to recursive table: %s", pCte->zName
);
return WRC_Abort;
}
assert( pTab->nRef==1 || ((pSel->selFlags&SF_Recursive) && pTab->nRef==2 ));
pCte->zErr = "circular reference: %s";
sqlite3WalkSelect(pWalker, bMayRecursive ? pSel->pPrior : pSel);
for(pLeft=pSel; pLeft->pPrior; pLeft=pLeft->pPrior);
pEList = pLeft->pEList;
if( pCte->pCols ){
if( pEList->nExpr!=pCte->pCols->nExpr ){
sqlite3ErrorMsg(pParse, "table %s has %d values for %d columns",
pCte->zName, pEList->nExpr, pCte->pCols->nExpr
);
return WRC_Abort;
}
pEList = pCte->pCols;
}
selectColumnsFromExprList(pParse, pEList, &pTab->nCol, &pTab->aCol);
if( bMayRecursive ){
if( pSel->selFlags & SF_Recursive ){
pCte->zErr = "multiple recursive references: %s";
}else{
pCte->zErr = "recursive reference in a subquery: %s";
}
sqlite3WalkSelect(pWalker, pSel);
}
pCte->zErr = 0;
}
return SQLITE_OK;
}
#endif
#ifndef SQLITE_OMIT_CTE
/*
** If the SELECT passed as the second argument has an associated WITH
** clause, pop it from the stack stored as part of the Parse object.
**
** This function is used as the xSelectCallback2() callback by
** sqlite3SelectExpand() when walking a SELECT tree to resolve table
** names and other FROM clause elements.
*/
static void selectPopWith(Walker *pWalker, Select *p){
Parse *pParse = pWalker->pParse;
if( p->pWith ){
assert( pParse->pWith==p->pWith );
pParse->pWith = p->pWith->pOuter;
}
return WRC_Continue;
}
#else
#define selectPopWith 0
#endif
/*
** This routine is a Walker callback for "expanding" a SELECT statement.
** "Expanding" means to do the following:
@@ -3437,6 +3720,7 @@ static int selectExpander(Walker *pWalker, Select *p){
}
pTabList = p->pSrc;
pEList = p->pEList;
sqlite3WithPush(pParse, p->pWith, 0);
/* Make sure cursor numbers have been assigned to all entries in
** the FROM clause of the SELECT statement.
@@ -3449,12 +3733,21 @@ static int selectExpander(Walker *pWalker, Select *p){
*/
for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
Table *pTab;
assert( pFrom->isRecursive==0 || pFrom->pTab );
if( pFrom->isRecursive ) continue;
if( pFrom->pTab!=0 ){
/* This statement has already been prepared. There is no need
** to go further. */
assert( i==0 );
#ifndef SQLITE_OMIT_CTE
selectPopWith(pWalker, p);
#endif
return WRC_Prune;
}
#ifndef SQLITE_OMIT_CTE
if( withExpand(pWalker, pFrom) ) return WRC_Abort;
if( pFrom->pTab ) {} else
#endif
if( pFrom->zName==0 ){
#ifndef SQLITE_OMIT_SUBQUERY
Select *pSel = pFrom->pSelect;
@@ -3717,6 +4010,7 @@ static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
sqlite3WalkSelect(&w, pSelect);
}
w.xSelectCallback = selectExpander;
w.xSelectCallback2 = selectPopWith;
sqlite3WalkSelect(&w, pSelect);
}
@@ -3735,7 +4029,7 @@ static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
** at that point because identifiers had not yet been resolved. This
** routine is called after identifier resolution.
*/
static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
Parse *pParse;
int i;
SrcList *pTabList;
@@ -3751,13 +4045,13 @@ static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
if( ALWAYS(pTab!=0) && (pTab->tabFlags & TF_Ephemeral)!=0 ){
/* A sub-query in the FROM clause of a SELECT */
Select *pSel = pFrom->pSelect;
assert( pSel );
while( pSel->pPrior ) pSel = pSel->pPrior;
selectAddColumnTypeAndCollation(pParse, pTab, pSel);
if( pSel ){
while( pSel->pPrior ) pSel = pSel->pPrior;
selectAddColumnTypeAndCollation(pParse, pTab, pSel);
}
}
}
}
return WRC_Continue;
}
#endif
@@ -3773,10 +4067,9 @@ static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
#ifndef SQLITE_OMIT_SUBQUERY
Walker w;
memset(&w, 0, sizeof(w));
w.xSelectCallback = selectAddSubqueryTypeInfo;
w.xSelectCallback2 = selectAddSubqueryTypeInfo;
w.xExprCallback = exprWalkNoop;
w.pParse = pParse;
w.bSelectDepthFirst = 1;
sqlite3WalkSelect(&w, pSelect);
#endif
}

1
src/sqlite.h.in
View File

@@ -2561,6 +2561,7 @@ int sqlite3_set_authorizer(
#define SQLITE_FUNCTION 31 /* NULL Function Name */
#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
#define SQLITE_COPY 0 /* No longer used */
#define SQLITE_RECURSIVE 33 /* NULL NULL */
/*
** CAPI3REF: Tracing And Profiling Functions

35
src/sqliteInt.h
View File

@@ -760,6 +760,7 @@ typedef struct VTable VTable;
typedef struct VtabCtx VtabCtx;
typedef struct Walker Walker;
typedef struct WhereInfo WhereInfo;
typedef struct With With;
/*
** Defer sourcing vdbe.h and btree.h until after the "u8" and
@@ -1428,7 +1429,7 @@ struct Table {
};
/*
** Allowed values for Tabe.tabFlags.
** Allowed values for Table.tabFlags.
*/
#define TF_Readonly 0x01 /* Read-only system table */
#define TF_Ephemeral 0x02 /* An ephemeral table */
@@ -1436,6 +1437,7 @@ struct Table {
#define TF_Autoincrement 0x08 /* Integer primary key is autoincrement */
#define TF_Virtual 0x10 /* Is a virtual table */
#define TF_WithoutRowid 0x20 /* No rowid used. PRIMARY KEY is the key */
#define TF_Recursive 0x40 /* Recursive reference within CTE */
/*
@@ -2017,6 +2019,7 @@ struct SrcList {
unsigned notIndexed :1; /* True if there is a NOT INDEXED clause */
unsigned isCorrelated :1; /* True if sub-query is correlated */
unsigned viaCoroutine :1; /* Implemented as a co-routine */
unsigned isRecursive :1; /* True for recursive reference in WITH */
#ifndef SQLITE_OMIT_EXPLAIN
u8 iSelectId; /* If pSelect!=0, the id of the sub-select in EQP */
#endif
@@ -2143,6 +2146,7 @@ struct Select {
Select *pRightmost; /* Right-most select in a compound select statement */
Expr *pLimit; /* LIMIT expression. NULL means not used. */
Expr *pOffset; /* OFFSET expression. NULL means not used. */
With *pWith; /* WITH clause attached to this select. Or NULL. */
};
/*
@@ -2160,6 +2164,7 @@ struct Select {
#define SF_Materialize 0x0100 /* Force materialization of views */
#define SF_NestedFrom 0x0200 /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert 0x0400 /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive 0x0800 /* The recursive part of a recursive CTE */
/*
@@ -2180,6 +2185,7 @@ struct Select {
#define SRT_Table 8 /* Store result as data with an automatic rowid */
#define SRT_EphemTab 9 /* Create transient tab and store like SRT_Table */
#define SRT_Coroutine 10 /* Generate a single row of result */
#define SRT_DistTable 11 /* Like SRT_TABLE, but unique results only */
/*
** An instance of this object describes where to put of the results of
@@ -2364,6 +2370,8 @@ struct Parse {
#endif
Table *pZombieTab; /* List of Table objects to delete after code gen */
TriggerPrg *pTriggerPrg; /* Linked list of coded triggers */
With *pWith; /* Current WITH clause, or NULL */
u8 bFreeWith; /* True if pWith should be freed with parser */
};
/*
@@ -2605,9 +2613,9 @@ struct Sqlite3Config {
struct Walker {
int (*xExprCallback)(Walker*, Expr*); /* Callback for expressions */
int (*xSelectCallback)(Walker*,Select*); /* Callback for SELECTs */
void (*xSelectCallback2)(Walker*,Select*);/* Second callback for SELECTs */
Parse *pParse; /* Parser context. */
int walkerDepth; /* Number of subqueries */
u8 bSelectDepthFirst; /* Do subqueries first */
union { /* Extra data for callback */
NameContext *pNC; /* Naming context */
int i; /* Integer value */
@@ -2631,6 +2639,21 @@ int sqlite3WalkSelectFrom(Walker*, Select*);
#define WRC_Prune 1 /* Omit children but continue walking siblings */
#define WRC_Abort 2 /* Abandon the tree walk */
/*
** An instance of this structure represents a set of one or more CTEs
** (common table expressions) created by a single WITH clause.
*/
struct With {
int nCte; /* Number of CTEs in the WITH clause */
With *pOuter; /* Containing WITH clause, or NULL */
struct Cte { /* For each CTE in the WITH clause.... */
char *zName; /* Name of this CTE */
ExprList *pCols; /* List of explicit column names, or NULL */
Select *pSelect; /* The definition of this CTE */
const char *zErr; /* Error message for circular references */
} a[1];
};
/*
** Assuming zIn points to the first byte of a UTF-8 character,
** advance zIn to point to the first byte of the next UTF-8 character.
@@ -3329,6 +3352,14 @@ const char *sqlite3JournalModename(int);
int sqlite3Checkpoint(sqlite3*, int, int, int*, int*);
int sqlite3WalDefaultHook(void*,sqlite3*,const char*,int);
#endif
#ifndef SQLITE_OMIT_CTE
With *sqlite3WithAdd(Parse*,With*,Token*,ExprList*,Select*);
void sqlite3WithDelete(sqlite3*,With*);
void sqlite3WithPush(Parse*, With*, u8);
#else
#define sqlite3WithPush(x,y,z)
#define sqlite3WithDelete(x,y)
#endif
/* Declarations for functions in fkey.c. All of these are replaced by
** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign

1
src/tclsqlite.c
View File

@@ -914,6 +914,7 @@ static int auth_callback(
case SQLITE_DROP_VTABLE : zCode="SQLITE_DROP_VTABLE"; break;
case SQLITE_FUNCTION : zCode="SQLITE_FUNCTION"; break;
case SQLITE_SAVEPOINT : zCode="SQLITE_SAVEPOINT"; break;
case SQLITE_RECURSIVE : zCode="SQLITE_RECURSIVE"; break;
default : zCode="????"; break;
}
Tcl_DStringInit(&str);

6
src/test_config.c
View File

@@ -225,6 +225,12 @@ static void set_options(Tcl_Interp *interp){
Tcl_SetVar2(interp, "sqlite_options", "check", "1", TCL_GLOBAL_ONLY);
#endif
#ifdef SQLITE_OMIT_CTE
Tcl_SetVar2(interp, "sqlite_options", "cte", "0", TCL_GLOBAL_ONLY);
#else
Tcl_SetVar2(interp, "sqlite_options", "cte", "1", TCL_GLOBAL_ONLY);
#endif
#ifdef SQLITE_ENABLE_COLUMN_METADATA
Tcl_SetVar2(interp, "sqlite_options", "columnmetadata", "1", TCL_GLOBAL_ONLY);
#else

1
src/tokenize.c
View File

@@ -494,6 +494,7 @@ abort_parse:
sqlite3DeleteTable(db, pParse->pNewTable);
}
if( pParse->bFreeWith ) sqlite3WithDelete(db, pParse->pWith);
sqlite3DeleteTrigger(db, pParse->pNewTrigger);
for(i=pParse->nzVar-1; i>=0; i--) sqlite3DbFree(db, pParse->azVar[i]);
sqlite3DbFree(db, pParse->azVar);

26
src/vdbe.c
View File

@@ -3369,6 +3369,32 @@ case OP_OpenEphemeral: {
break;
}
#ifndef SQLITE_OMIT_CTE
/* Opcode: SwapCursors P1 P2 * * *
**
** Parameters P1 and P2 are both cursors opened by the OpenEphemeral
** opcode. This opcode deletes the contents of epheremal table P1,
** then renames P2 to P1 and P1 to P2. In other words, following this
** opcode cursor P2 is open on an empty table and P1 is open on the
** table that was initially accessed by P2.
*/
case OP_SwapCursors: {
Mem tmp;
VdbeCursor *pTmp;
tmp = p->aMem[p->nMem - pOp->p1];
p->aMem[p->nMem - pOp->p1] = p->aMem[p->nMem - pOp->p2];
p->aMem[p->nMem - pOp->p2] = tmp;
pTmp = p->apCsr[pOp->p1];
p->apCsr[pOp->p1] = p->apCsr[pOp->p2];
p->apCsr[pOp->p2] = pTmp;
rc = sqlite3BtreeClearTable(pTmp->pBt, MASTER_ROOT + !pTmp->isTable, 0);
break;
}
#endif /* ifndef SQLITE_OMIT_CTE */
/* Opcode: SorterOpen P1 * * P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens

23
src/walker.c
View File

@@ -113,9 +113,12 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
/*
** Call sqlite3WalkExpr() for every expression in Select statement p.
** Invoke sqlite3WalkSelect() for subqueries in the FROM clause and
** on the compound select chain, p->pPrior. Invoke the xSelectCallback()
** either before or after the walk of expressions and FROM clause, depending
** on whether pWalker->bSelectDepthFirst is false or true, respectively.
** on the compound select chain, p->pPrior.
**
** If it is not NULL, the xSelectCallback() callback is invoked before
** the walk of the expressions and FROM clause. The xSelectCallback2()
** method, if it is not NULL, is invoked following the walk of the
** expressions and FROM clause.
**
** Return WRC_Continue under normal conditions. Return WRC_Abort if
** there is an abort request.
@@ -125,11 +128,13 @@ int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
*/
int sqlite3WalkSelect(Walker *pWalker, Select *p){
int rc;
if( p==0 || pWalker->xSelectCallback==0 ) return WRC_Continue;
if( p==0 || (pWalker->xSelectCallback==0 && pWalker->xSelectCallback2==0) ){
return WRC_Continue;
}
rc = WRC_Continue;
pWalker->walkerDepth++;
while( p ){
if( !pWalker->bSelectDepthFirst ){
if( pWalker->xSelectCallback ){
rc = pWalker->xSelectCallback(pWalker, p);
if( rc ) break;
}
@@ -139,12 +144,8 @@ int sqlite3WalkSelect(Walker *pWalker, Select *p){
pWalker->walkerDepth--;
return WRC_Abort;
}
if( pWalker->bSelectDepthFirst ){
rc = pWalker->xSelectCallback(pWalker, p);
/* Depth-first search is currently only used for
** selectAddSubqueryTypeInfo() and that routine always returns
** WRC_Continue (0). So the following branch is never taken. */
if( NEVER(rc) ) break;
if( pWalker->xSelectCallback2 ){
pWalker->xSelectCallback2(pWalker, p);
}
p = p->pPrior;
}

1
src/where.c
View File

@@ -4196,6 +4196,7 @@ static int whereLoopAddBtree(
&& !pSrc->notIndexed
&& HasRowid(pTab)
&& !pSrc->isCorrelated
&& !pSrc->isRecursive
){
/* Generate auto-index WhereLoops */
WhereTerm *pTerm;