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Diffstat (limited to 'src/upsert.c')
| -rw-r--r-- | src/upsert.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/src/upsert.c b/src/upsert.c new file mode 100644 index 000000000..d98a82743 --- /dev/null +++ b/src/upsert.c @@ -0,0 +1,183 @@ +/* +** 2018-04-12 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** This file contains code to implement various aspects of UPSERT +** processing and handling of the Upsert object. +*/ +#include "sqliteInt.h" + +#ifndef SQLITE_OMIT_UPSERT +/* +** Free a list of Upsert objects +*/ +void sqlite3UpsertDelete(sqlite3 *db, Upsert *p){ + if( p ){ + sqlite3ExprListDelete(db, p->pUpsertTarget); + sqlite3ExprDelete(db, p->pUpsertTargetWhere); + sqlite3ExprListDelete(db, p->pUpsertSet); + sqlite3ExprDelete(db, p->pUpsertWhere); + sqlite3DbFree(db, p); + } +} + +/* +** Duplicate an Upsert object. +*/ +Upsert *sqlite3UpsertDup(sqlite3 *db, Upsert *p){ + if( p==0 ) return 0; + return sqlite3UpsertNew(db, + sqlite3ExprListDup(db, p->pUpsertTarget, 0), + sqlite3ExprDup(db, p->pUpsertTargetWhere, 0), + sqlite3ExprListDup(db, p->pUpsertSet, 0), + sqlite3ExprDup(db, p->pUpsertWhere, 0) + ); +} + +/* +** Create a new Upsert object. +*/ +Upsert *sqlite3UpsertNew( + sqlite3 *db, /* Determines which memory allocator to use */ + ExprList *pTarget, /* Target argument to ON CONFLICT, or NULL */ + Expr *pTargetWhere, /* Optional WHERE clause on the target */ + ExprList *pSet, /* UPDATE columns, or NULL for a DO NOTHING */ + Expr *pWhere /* WHERE clause for the ON CONFLICT UPDATE */ +){ + Upsert *pNew; + pNew = sqlite3DbMallocRaw(db, sizeof(Upsert)); + if( pNew==0 ){ + sqlite3ExprListDelete(db, pTarget); + sqlite3ExprDelete(db, pTargetWhere); + sqlite3ExprListDelete(db, pSet); + sqlite3ExprDelete(db, pWhere); + return 0; + }else{ + pNew->pUpsertTarget = pTarget; + pNew->pUpsertTargetWhere = pTargetWhere; + pNew->pUpsertSet = pSet; + pNew->pUpsertWhere = pWhere; + pNew->pUpsertIdx = 0; + } + return pNew; +} + +/* +** Analyze the ON CONFLICT clause described by pUpsert. Resolve all +** symbols in the conflict-target. +** +** Return SQLITE_OK if everything works, or an error code is something +** is wrong. +*/ +int sqlite3UpsertAnalyzeTarget( + Parse *pParse, /* The parsing context */ + SrcList *pTabList, /* Table into which we are inserting */ + Upsert *pUpsert /* The ON CONFLICT clauses */ +){ + Table *pTab; /* That table into which we are inserting */ + int rc; /* Result code */ + int iCursor; /* Cursor used by pTab */ + Index *pIdx; /* One of the indexes of pTab */ + ExprList *pTarget; /* The conflict-target clause */ + Expr *pTerm; /* One term of the conflict-target clause */ + NameContext sNC; /* Context for resolving symbolic names */ + Expr sCol[2]; /* Index column converted into an Expr */ + + assert( pTabList->nSrc==1 ); + assert( pTabList->a[0].pTab!=0 ); + assert( pUpsert!=0 ); + assert( pUpsert->pUpsertTarget!=0 ); + + /* Resolve all symbolic names in the conflict-target clause, which + ** includes both the list of columns and the optional partial-index + ** WHERE clause. + */ + memset(&sNC, 0, sizeof(sNC)); + sNC.pParse = pParse; + sNC.pSrcList = pTabList; + rc = sqlite3ResolveExprListNames(&sNC, pUpsert->pUpsertTarget); + if( rc ) return rc; + rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertTargetWhere); + if( rc ) return rc; + + /* Check to see if the conflict target matches the rowid. */ + pTab = pTabList->a[0].pTab; + pTarget = pUpsert->pUpsertTarget; + iCursor = pTabList->a[0].iCursor; + if( HasRowid(pTab) + && pTarget->nExpr==1 + && (pTerm = pTarget->a[0].pExpr)->op==TK_COLUMN + && (pTerm->iColumn==XN_ROWID || pTerm->iColumn==pTab->iPKey) + ){ + /* The conflict-target is the rowid of the primary table */ + assert( pUpsert->pUpsertIdx==0 ); + return SQLITE_OK; + } + + /* Initialize sCol[0..1] to be an expression parse tree for a + ** single column of an index. The sCol[0] node will be the TK_COLLATE + ** operator and sCol[1] will be the TK_COLUMN operator. Code below + ** will populate the specific collation and column number values + ** prior to comparing against the conflict-target expression. + */ + memset(sCol, 0, sizeof(sCol)); + sCol[0].op = TK_COLLATE; + sCol[0].pLeft = &sCol[1]; + sCol[1].op = TK_COLUMN; + sCol[1].iTable = pTabList->a[0].iCursor; + + /* Check for matches against other indexes */ + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ + int ii, jj, nn; + if( !IsUniqueIndex(pIdx) ) continue; + if( pTarget->nExpr!=pIdx->nKeyCol ) continue; + if( pIdx->pPartIdxWhere ){ + if( pUpsert->pUpsertTargetWhere==0 ) continue; + if( sqlite3ExprCompare(pParse, pUpsert->pUpsertTargetWhere, + pIdx->pPartIdxWhere, iCursor)!=0 ){ + continue; + } + } + nn = pIdx->nKeyCol; + for(ii=0; ii<nn; ii++){ + Expr *pExpr; + if( pIdx->aiColumn[ii]==XN_EXPR ){ + assert( pIdx->aColExpr!=0 ); + assert( pIdx->aColExpr->nExpr>ii ); + pExpr = pIdx->aColExpr->a[ii].pExpr; + }else{ + sCol[1].iColumn = pIdx->aiColumn[ii]; + sCol[0].u.zToken = (char*)pIdx->azColl[ii]; + pExpr = &sCol[0]; + } + for(jj=0; jj<nn; jj++){ + if( sqlite3ExprCompare(pParse, pTarget->a[jj].pExpr, pExpr,iCursor)<2 ){ + break; /* Column ii of the index matches column jj of target */ + } + } + if( jj>=nn ){ + /* The target contains no match for column jj of the index */ + break; + } + } + if( ii<nn ){ + /* Column ii of the index did not match any term of the conflict target. + ** Continue the search with the next index. */ + continue; + } + pUpsert->pUpsertIdx = pIdx; + return SQLITE_OK; + } + sqlite3ErrorMsg(pParse, "ON CONFLICT clause does not match any " + "PRIMARY KEY or UNIQUE constraint"); + return SQLITE_ERROR; +} + +#endif /* SQLITE_OMIT_UPSERT */ |