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If an update does not modify any child or parent key columns, omit foreign key processing for the statement.

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FossilOrigin-Name: edff3500058eb8ad2381f855ef7a09ecb680f7b8
This commit is contained in:
dan
2009-10-01 16:09:04 +00:00
parent d583502e7d
commit e7a94d8128
9 changed files with 94 additions and 59 deletions
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74
src/fkey.c
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@@ -672,14 +672,11 @@ void sqlite3FkDropTable(Parse *pParse, SrcList *pName, Table *pTab){
** For an UPDATE operation, this function is called twice. Once before
** the original record is deleted from the table using the calling convention
** described for DELETE. Then again after the original record is deleted
** but before the new record is inserted using the INSERT convention. In
** both cases parameter pChanges is passed the list of columns being
** updated by the statement.
** but before the new record is inserted using the INSERT convention.
*/
void sqlite3FkCheck(
Parse *pParse, /* Parse context */
Table *pTab, /* Row is being deleted from this table */
ExprList *pChanges, /* Changed columns if this is an UPDATE */
int regOld, /* Previous row data is stored here */
int regNew /* New row data is stored here */
){
@@ -725,11 +722,6 @@ void sqlite3FkCheck(
}
assert( pFKey->nCol==1 || (aiFree && pIdx) );
/* If the key does not overlap with the pChanges list, skip this FK. */
if( pChanges ){
/* TODO */
}
if( aiFree ){
aiCol = aiFree;
}else{
@@ -782,14 +774,6 @@ void sqlite3FkCheck(
}
assert( aiCol || pFKey->nCol==1 );
/* Check if this update statement has modified any of the child key
** columns for this foreign key constraint. If it has not, there is
** no need to search the child table for rows in violation. This is
** just an optimization. Things would work fine without this check. */
if( pChanges ){
/* TODO */
}
/* Create a SrcList structure containing a single table (the table
** the foreign key that refers to this table is attached to). This
** is required for the sqlite3WhereXXX() interface. */
@@ -822,14 +806,11 @@ void sqlite3FkCheck(
/*
** This function is called before generating code to update or delete a
** row contained in table pTab. If the operation is an update, then
** pChanges is a pointer to the list of columns to modify. If this is a
** delete, then pChanges is NULL.
** row contained in table pTab.
*/
u32 sqlite3FkOldmask(
Parse *pParse, /* Parse context */
Table *pTab, /* Table being modified */
ExprList *pChanges /* Non-NULL for UPDATE operations */
Table *pTab /* Table being modified */
){
u32 mask = 0;
if( pParse->db->flags&SQLITE_ForeignKeys ){
@@ -851,9 +832,13 @@ u32 sqlite3FkOldmask(
/*
** This function is called before generating code to update or delete a
** row contained in table pTab. If the operation is an update, then
** pChanges is a pointer to the list of columns to modify. If this is a
** delete, then pChanges is NULL.
** row contained in table pTab. If the operation is a DELETE, then
** parameter aChange is passed a NULL value. For an UPDATE, aChange points
** to an array of size N, where N is the number of columns in table pTab.
** If the i'th column is not modified by the UPDATE, then the corresponding
** entry in the aChange[] array is set to -1. If the column is modified,
** the value is 0 or greater. Parameter chngRowid is set to true if the
** UPDATE statement modifies the rowid fields of the table.
**
** If any foreign key processing will be required, this function returns
** true. If there is no foreign key related processing, this function
@@ -862,10 +847,45 @@ u32 sqlite3FkOldmask(
int sqlite3FkRequired(
Parse *pParse, /* Parse context */
Table *pTab, /* Table being modified */
ExprList *pChanges /* Non-NULL for UPDATE operations */
int *aChange, /* Non-NULL for UPDATE operations */
int chngRowid /* True for UPDATE that affects rowid */
){
if( pParse->db->flags&SQLITE_ForeignKeys ){
if( sqlite3FkReferences(pTab) || pTab->pFKey ) return 1;
if( !aChange ){
/* A DELETE operation. Foreign key processing is required if the
** table in question is either the child or parent table for any
** foreign key constraint. */
return (sqlite3FkReferences(pTab) || pTab->pFKey);
}else{
/* This is an UPDATE. Foreign key processing is only required if the
** operation modifies one or more child or parent key columns. */
int i;
FKey *p;
/* Check if any child key columns are being modified. */
for(p=pTab->pFKey; p; p=p->pNextFrom){
for(i=0; i<p->nCol; i++){
int iChildKey = p->aCol[i].iFrom;
if( aChange[iChildKey]>=0 ) return 1;
if( iChildKey==pTab->iPKey && chngRowid ) return 1;
}
}
/* Check if any parent key columns are being modified. */
for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
for(i=0; i<p->nCol; i++){
char *zKey = p->aCol[i].zCol;
int iKey;
for(iKey=0; iKey<pTab->nCol; iKey++){
Column *pCol = &pTab->aCol[iKey];
if( (zKey ? !sqlite3StrICmp(pCol->zName, zKey) : pCol->isPrimKey) ){
if( aChange[iKey]>=0 ) return 1;
if( iKey==pTab->iPKey && chngRowid ) return 1;
}
}
}
}
}
}
return 0;
}