Add missing comments to fkey.c. Also, change the terminology used for comments and names in fkey.c from "referenced/referencing" to "parent/child". This is arguably less correct, but is easier to follow.
FossilOrigin-Name: 540c2d18e14c277b55f95729fbafc04ca66466b2
diff --git a/src/build.c b/src/build.c
index 06c0a0f..53d8b32 100644
--- a/src/build.c
+++ b/src/build.c
@@ -2226,9 +2226,8 @@
}
}
pFKey->isDeferred = 0;
- pFKey->deleteConf = (u8)(flags & 0xff);
- pFKey->updateConf = (u8)((flags >> 8 ) & 0xff);
- pFKey->insertConf = (u8)((flags >> 16 ) & 0xff);
+ pFKey->aAction[0] = (u8)(flags & 0xff); /* ON DELETE action */
+ pFKey->aAction[1] = (u8)((flags >> 8 ) & 0xff); /* ON UPDATE action */
pNextTo = (FKey *)sqlite3HashInsert(&p->pSchema->fkeyHash,
pFKey->zTo, sqlite3Strlen30(pFKey->zTo), (void *)pFKey
diff --git a/src/fkey.c b/src/fkey.c
index 1e64310..2dc93b6 100644
--- a/src/fkey.c
+++ b/src/fkey.c
@@ -48,26 +48,26 @@
**
** INSERT operations:
**
-** I.1) For each FK for which the table is the referencing table, search
-** the referenced table for a match. If none is found, throw an
+** I.1) For each FK for which the table is the child table, search
+** the parent table for a match. If none is found, throw an
** exception for an immediate FK, or increment the counter for a
** deferred FK.
**
-** I.2) For each deferred FK for which the table is the referenced table,
-** search the referencing table for rows that correspond to the new
-** row in the referenced table. Decrement the counter for each row
+** I.2) For each deferred FK for which the table is the parent table,
+** search the child table for rows that correspond to the new
+** row in the parent table. Decrement the counter for each row
** found (as the constraint is now satisfied).
**
** DELETE operations:
**
-** D.1) For each deferred FK for which the table is the referencing table,
-** search the referenced table for a row that corresponds to the
-** deleted row in the referencing table. If such a row is not found,
+** D.1) For each deferred FK for which the table is the child table,
+** search the parent table for a row that corresponds to the
+** deleted row in the child table. If such a row is not found,
** decrement the counter.
**
-** D.2) For each FK for which the table is the referenced table, search
-** the referencing table for rows that correspond to the deleted row
-** in the referenced table. For each found, throw an exception for an
+** D.2) For each FK for which the table is the parent table, search
+** the child table for rows that correspond to the deleted row
+** in the parent table. For each found, throw an exception for an
** immediate FK, or increment the counter for a deferred FK.
**
** UPDATE operations:
@@ -87,9 +87,8 @@
**
** TODO: How should dropping a table be handled? How should renaming a
** table be handled?
-*/
-
-/*
+**
+**
** Query API Notes
** ---------------
**
@@ -99,8 +98,19 @@
** row are required by the FK processing VDBE code (i.e. if FKs were
** implemented using triggers, which of the old.* columns would be
** accessed). No information is required by the code-generator before
-** coding an INSERT operation.
+** coding an INSERT operation. The functions used by the UPDATE/DELETE
+** generation code to query for this information are:
**
+** sqlite3FkRequired() - Test to see if FK processing is required.
+** sqlite3FkOldmask() - Query for the set of required old.* columns.
+**
+**
+** Externally accessible module functions
+** --------------------------------------
+**
+** sqlite3FkCheck() - Check for foreign key violations.
+** sqlite3FkActions() - Code triggers for ON UPDATE/ON DELETE actions.
+** sqlite3FkDelete() - Delete an FKey structure.
*/
/*
@@ -121,51 +131,63 @@
*/
/*
-** ON UPDATE and ON DELETE clauses
-** -------------------------------
-*/
-
-/*
-** Externally accessible module functions
-** --------------------------------------
-**
-** sqlite3FkRequired()
-** sqlite3FkOldmask()
-**
-** sqlite3FkCheck()
-** sqlite3FkActions()
-**
-** sqlite3FkDelete()
-**
-*/
-
-/*
-** A foreign key constraint requires that the key columns in the referenced
+** A foreign key constraint requires that the key columns in the parent
** table are collectively subject to a UNIQUE or PRIMARY KEY constraint.
-** Given that pTo is the referenced table for foreign key constraint
-** pFKey, check that the columns in pTo are indeed subject to a such a
-** constraint. If they are not, return non-zero and leave an error in pParse.
+** Given that pParent is the parent table for foreign key constraint pFKey,
+** search the schema a unique index on the parent key columns.
**
-** If an error does not occur, return zero.
+** If successful, zero is returned. If the parent key is an INTEGER PRIMARY
+** KEY column, then output variable *ppIdx is set to NULL. Otherwise, *ppIdx
+** is set to point to the unique index.
+**
+** If the parent key consists of a single column (the foreign key constraint
+** is not a composite foreign key), output variable *paiCol is set to NULL.
+** Otherwise, it is set to point to an allocated array of size N, where
+** N is the number of columns in the parent key. The first element of the
+** array is the index of the child table column that is mapped by the FK
+** constraint to the parent table column stored in the left-most column
+** of index *ppIdx. The second element of the array is the index of the
+** child table column that corresponds to the second left-most column of
+** *ppIdx, and so on.
+**
+** If the required index cannot be found, either because:
+**
+** 1) The named parent key columns do not exist, or
+**
+** 2) The named parent key columns do exist, but are not subject to a
+** UNIQUE or PRIMARY KEY constraint, or
+**
+** 3) No parent key columns were provided explicitly as part of the
+** foreign key definition, and the parent table does not have a
+** PRIMARY KEY, or
+**
+** 4) No parent key columns were provided explicitly as part of the
+** foreign key definition, and the PRIMARY KEY of the parent table
+** consists of a a different number of columns to the child key in
+** the child table.
+**
+** then non-zero is returned, and a "foreign key mismatch" error loaded
+** into pParse. If an OOM error occurs, non-zero is returned and the
+** pParse->db->mallocFailed flag is set.
*/
static int locateFkeyIndex(
Parse *pParse, /* Parse context to store any error in */
- Table *pTo, /* Referenced table */
+ Table *pParent, /* Parent table of FK constraint pFKey */
FKey *pFKey, /* Foreign key to find index for */
- Index **ppIdx, /* OUT: Unique index on referenced table */
+ Index **ppIdx, /* OUT: Unique index on parent table */
int **paiCol /* OUT: Map of index columns in pFKey */
){
- Index *pIdx = 0;
- int *aiCol = 0;
- int nCol = pFKey->nCol;
- char *zFirst = pFKey->aCol[0].zCol;
+ Index *pIdx = 0; /* Value to return via *ppIdx */
+ int *aiCol = 0; /* Value to return via *paiCol */
+ int nCol = pFKey->nCol; /* Number of columns in parent key */
+ char *zKey = pFKey->aCol[0].zCol; /* Name of left-most parent key column */
/* The caller is responsible for zeroing output parameters. */
assert( ppIdx && *ppIdx==0 );
assert( !paiCol || *paiCol==0 );
/* If this is a non-composite (single column) foreign key, check if it
- ** maps to the INTEGER PRIMARY KEY of table pTo. If so, leave *ppIdx
+ ** maps to the INTEGER PRIMARY KEY of table pParent. If so, leave *ppIdx
** and *paiCol set to zero and return early.
**
** Otherwise, for a composite foreign key (more than one column), allocate
@@ -177,14 +199,14 @@
**
** 1) The FK is explicitly mapped to "rowid", "oid" or "_rowid_", or
** 2) There is an explicit INTEGER PRIMARY KEY column and the FK is
- ** implicitly mapped to the primary key of table pTo, or
+ ** implicitly mapped to the primary key of table pParent, or
** 3) The FK is explicitly mapped to a column declared as INTEGER
** PRIMARY KEY.
*/
- if( zFirst && sqlite3IsRowid(zFirst) ) return 0;
- if( pTo->iPKey>=0 ){
- if( !zFirst ) return 0;
- if( !sqlite3StrICmp(pTo->aCol[pTo->iPKey].zName, zFirst) ) return 0;
+ if( zKey && sqlite3IsRowid(zKey) ) return 0;
+ if( pParent->iPKey>=0 ){
+ if( !zKey ) return 0;
+ if( !sqlite3StrICmp(pParent->aCol[pParent->iPKey].zName, zKey) ) return 0;
}
}else if( paiCol ){
assert( nCol>1 );
@@ -193,27 +215,27 @@
*paiCol = aiCol;
}
- for(pIdx=pTo->pIndex; pIdx; pIdx=pIdx->pNext){
+ for(pIdx=pParent->pIndex; pIdx; pIdx=pIdx->pNext){
if( pIdx->nColumn==nCol && pIdx->onError!=OE_None ){
/* pIdx is a UNIQUE index (or a PRIMARY KEY) and has the right number
** of columns. If each indexed column corresponds to a foreign key
** column of pFKey, then this index is a winner. */
- if( zFirst==0 ){
- /* If zFirst is NULL, then this foreign key is implicitly mapped to
- ** the PRIMARY KEY of table pTo. The PRIMARY KEY index may be
+ if( zKey==0 ){
+ /* If zKey is NULL, then this foreign key is implicitly mapped to
+ ** the PRIMARY KEY of table pParent. The PRIMARY KEY index may be
** identified by the test (Index.autoIndex==2). */
if( pIdx->autoIndex==2 ){
if( aiCol ) memcpy(aiCol, pIdx->aiColumn, sizeof(int)*nCol);
break;
}
}else{
- /* If zFirst is non-NULL, then this foreign key was declared to
- ** map to an explicit list of columns in table pTo. Check if this
+ /* If zKey is non-NULL, then this foreign key was declared to
+ ** map to an explicit list of columns in table pParent. Check if this
** index matches those columns. */
int i, j;
for(i=0; i<nCol; i++){
- char *zIdxCol = pTo->aCol[pIdx->aiColumn[i]].zName;
+ char *zIdxCol = pParent->aCol[pIdx->aiColumn[i]].zName;
for(j=0; j<nCol; j++){
if( sqlite3StrICmp(pFKey->aCol[j].zCol, zIdxCol)==0 ){
if( aiCol ) aiCol[i] = pFKey->aCol[j].iFrom;
@@ -237,34 +259,60 @@
return 0;
}
-static void fkCheckReference(
+/*
+** This function is called when a row is inserted into the child table of
+** foreign key constraint pFKey and, if pFKey is deferred, when a row is
+** deleted from the child table of pFKey. If an SQL UPDATE is executed on
+** the child table of pFKey, this function is invoked twice for each row
+** affected - once to "delete" the old row, and then again to "insert" the
+** new row.
+**
+** Each time it is called, this function generates VDBE code to locate the
+** row in the parent table that corresponds to the row being inserted into
+** or deleted from the child table. If the parent row can be found, no
+** special action is taken. Otherwise, if the parent row can *not* be
+** found in the parent table:
+**
+** Operation | FK type | Action taken
+** --------------------------------------------------------------------------
+** INSERT immediate Throw a "foreign key constraint failed" exception.
+**
+** INSERT deferred Increment the "deferred constraint counter".
+**
+** DELETE deferred Decrement the "deferred constraint counter".
+**
+** This function is never called for a delete on the child table of an
+** immediate foreign key constraint. These operations are identified in
+** the comment at the top of this file (fkey.c) as "I.1" and "D.1".
+*/
+static void fkLookupParent(
Parse *pParse, /* Parse context */
int iDb, /* Index of database housing pTab */
- Table *pTab, /* Table referenced by FK pFKey */
- Index *pIdx, /* Index ensuring uniqueness of FK in pTab */
- FKey *pFKey, /* Foreign key to check */
- int *aiCol, /* Map from FK column to referencing table column */
- int regData, /* Address of array containing referencing row */
+ Table *pTab, /* Parent table of FK pFKey */
+ Index *pIdx, /* Unique index on parent key columns in pTab */
+ FKey *pFKey, /* Foreign key constraint */
+ int *aiCol, /* Map from parent key columns to child table columns */
+ int regData, /* Address of array containing child table row */
int nIncr /* If deferred FK, increment counter by this */
){
- int i;
- Vdbe *v = sqlite3GetVdbe(pParse);
- int iCur = pParse->nTab - 1;
- int iOk = sqlite3VdbeMakeLabel(v);
+ int i; /* Iterator variable */
+ Vdbe *v = sqlite3GetVdbe(pParse); /* Vdbe to add code to */
+ int iCur = pParse->nTab - 1; /* Cursor number to use */
+ int iOk = sqlite3VdbeMakeLabel(v); /* jump here if parent key found */
assert( pFKey->isDeferred || nIncr==1 );
- /* Check if any of the key columns in the referencing table are
+ /* Check if any of the key columns in the child table row are
** NULL. If any are, then the constraint is satisfied. No need
- ** to search for a matching row in the referenced table. */
+ ** to search for a matching row in the parent table. */
for(i=0; i<pFKey->nCol; i++){
int iReg = aiCol[i] + regData + 1;
sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iOk);
}
if( pIdx==0 ){
- /* If pIdx is NULL, then the foreign key constraint references the
- ** INTEGER PRIMARY KEY column in the referenced table (table pTab). */
+ /* If pIdx is NULL, then the parent key is the INTEGER PRIMARY KEY
+ ** column of the parent table (table pTab). */
int iReg = pFKey->aCol[0].iFrom + regData + 1;
sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iReg);
@@ -307,12 +355,37 @@
sqlite3VdbeResolveLabel(v, iOk);
}
-static void fkScanReferences(
+/*
+** This function is called to generate code executed when a row is deleted
+** from the parent table of foreign key constraint pFKey and, if pFKey is
+** deferred, when a row is inserted into the same table. When generating
+** code for an SQL UPDATE operation, this function may be called twice -
+** once to "delete" the old row and once to "insert" the new row.
+**
+** The code generated by this function scans through the rows in the child
+** table that correspond to the parent table row being deleted or inserted.
+** For each child row found, one of the following actions is taken:
+**
+** Operation | FK type | Action taken
+** --------------------------------------------------------------------------
+** DELETE immediate Throw a "foreign key constraint failed" exception.
+**
+** DELETE deferred Increment the "deferred constraint counter".
+** Or, if the ON (UPDATE|DELETE) action is RESTRICT,
+** throw a "foreign key constraint failed" exception.
+**
+** INSERT deferred Decrement the "deferred constraint counter".
+**
+** This function is never called for an INSERT operation on the parent table
+** of an immediate foreign key constraint. These operations are identified in
+** the comment at the top of this file (fkey.c) as "I.2" and "D.2".
+*/
+static void fkScanChildren(
Parse *pParse, /* Parse context */
SrcList *pSrc, /* SrcList containing the table to scan */
Index *pIdx, /* Foreign key index */
FKey *pFKey, /* Foreign key relationship */
- int *aiCol, /* Map from FK to referenced table columns */
+ int *aiCol, /* Map from pIdx cols to child table cols */
int regData, /* Referenced table data starts here */
int nIncr /* Amount to increment deferred counter by */
){
@@ -323,11 +396,11 @@
WhereInfo *pWInfo; /* Context used by sqlite3WhereXXX() */
for(i=0; i<pFKey->nCol; i++){
- Expr *pLeft; /* Value from deleted row */
- Expr *pRight; /* Column ref to referencing table */
+ Expr *pLeft; /* Value from parent table row */
+ Expr *pRight; /* Column ref to child table */
Expr *pEq; /* Expression (pLeft = pRight) */
- int iCol; /* Index of column in referencing table */
- const char *zCol; /* Name of column in referencing table */
+ int iCol; /* Index of column in child table */
+ const char *zCol; /* Name of column in child table */
pLeft = sqlite3Expr(db, TK_REGISTER, 0);
if( pLeft ){
@@ -374,7 +447,7 @@
/*
** This function returns a pointer to the head of a linked list of FK
-** constraints that refer to the table passed as an argument. For example,
+** constraints for which table pTab is the parent table. For example,
** given the following schema:
**
** CREATE TABLE t1(a PRIMARY KEY);
@@ -383,13 +456,22 @@
** Calling this function with table "t1" as an argument returns a pointer
** to the FKey structure representing the foreign key constraint on table
** "t2". Calling this function with "t2" as the argument would return a
-** NULL pointer (as there are no FK constraints that refer to t2).
+** NULL pointer (as there are no FK constraints for which t2 is the parent
+** table).
*/
static FKey *fkRefering(Table *pTab){
int nName = sqlite3Strlen30(pTab->zName);
return (FKey *)sqlite3HashFind(&pTab->pSchema->fkeyHash, pTab->zName, nName);
}
+/*
+** The second argument is a Trigger structure allocated by the
+** fkActionTrigger() routine. This function deletes the Trigger structure
+** and all of its sub-components.
+**
+** The Trigger structure or any of its sub-components may be allocated from
+** the lookaside buffer belonging to database handle dbMem.
+*/
static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
if( p ){
TriggerStep *pStep = p->step_list;
@@ -400,6 +482,29 @@
}
}
+/*
+** This function is called when inserting, deleting or updating a row of
+** table pTab to generate VDBE code to perform foreign key constraint
+** processing for the operation.
+**
+** For a DELETE operation, parameter regOld is passed the index of the
+** first register in an array of (pTab->nCol+1) registers containing the
+** rowid of the row being deleted, followed by each of the column values
+** of the row being deleted, from left to right. Parameter regNew is passed
+** zero in this case.
+**
+** For an UPDATE operation, regOld is the first in an array of (pTab->nCol+1)
+** registers containing the old rowid and column values of the row being
+** updated, and regNew is the first in an array of the same size containing
+** the corresponding new values. Parameter pChanges is passed the list of
+** columns being updated by the statement.
+**
+** For an INSERT operation, regOld is passed zero and regNew is passed the
+** first register of an array of (pTab->nCol+1) registers containing the new
+** row data.
+**
+** If an error occurs, an error message is left in the pParse structure.
+*/
void sqlite3FkCheck(
Parse *pParse, /* Parse context */
Table *pTab, /* Row is being deleted from this table */
@@ -425,21 +530,25 @@
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
zDb = db->aDb[iDb].zName;
- /* Loop through all the foreign key constraints attached to the table. */
+ /* Loop through all the foreign key constraints for which pTab is the
+ ** child table (the table that the foreign key definition is part of). */
for(pFKey=pTab->pFKey; pFKey; pFKey=pFKey->pNextFrom){
- Table *pTo; /* Table referenced by this FK */
+ Table *pTo; /* Parent table of foreign key pFKey */
Index *pIdx = 0; /* Index on key columns in pTo */
int *aiFree = 0;
int *aiCol;
int iCol;
int i;
+ /* If this is a DELETE operation and the foreign key is not deferred,
+ ** nothing to do. A DELETE on the child table cannot cause the FK
+ ** constraint to fail. */
if( pFKey->isDeferred==0 && regNew==0 ) continue;
- /* Find the table this foreign key references. Also find a unique
- ** index on the referenced table that corresponds to the key columns.
- ** If either of these things cannot be located, set an error in pParse
- ** and return early. */
+ /* Find the parent table of this foreign key. Also find a unique index
+ ** on the parent key columns in the parent table. If either of these
+ ** schema items cannot be located, set an error in pParse and return
+ ** early. */
pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb);
if( !pTo || locateFkeyIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ) return;
assert( pFKey->nCol==1 || (aiFree && pIdx) );
@@ -461,17 +570,17 @@
}
}
- /* Take a shared-cache advisory read-lock on the referenced table.
- ** Allocate a cursor to use to search the unique index on the FK
- ** columns in the referenced table. */
+ /* Take a shared-cache advisory read-lock on the parent table. Allocate
+ ** a cursor to use to search the unique index on the parent key columns
+ ** in the parent table. */
sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
pParse->nTab++;
if( regOld!=0 && pFKey->isDeferred ){
- fkCheckReference(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1);
+ fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1);
}
if( regNew!=0 ){
- fkCheckReference(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1);
+ fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1);
}
sqlite3DbFree(db, aiFree);
@@ -494,16 +603,16 @@
*/
if( pFKey->isDeferred==0 ){
if( regOld==0 ) continue; /* 1 */
- if( regNew!=0 && pFKey->updateConf>OE_Restrict ) continue; /* 2 */
- if( regNew==0 && pFKey->deleteConf>OE_Restrict ) continue; /* 3 */
+ if( regNew!=0 && pFKey->aAction[1]>OE_Restrict ) continue; /* 2 */
+ if( regNew==0 && pFKey->aAction[0]>OE_Restrict ) continue; /* 3 */
}
if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ) return;
assert( aiCol || pFKey->nCol==1 );
- /* Check if this update statement has modified any of the key columns
- ** for this foreign key constraint. If it has not, there is no need
- ** to search the referencing table for rows in violation. This is
+ /* 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 */
@@ -519,8 +628,8 @@
pSrc->a->iCursor = pParse->nTab++;
/* If this is an UPDATE, and none of the columns associated with this
- ** FK have been modified, do not scan the referencing table. Unlike
- ** the compile-time test implemented above, this is not just an
+ ** FK have been modified, do not scan the child table. Unlike the
+ ** compile-time test implemented above, this is not just an
** optimization. It is required so that immediate foreign keys do not
** throw exceptions when the user executes a statement like:
**
@@ -537,18 +646,17 @@
}
if( regNew!=0 && pFKey->isDeferred ){
- fkScanReferences(pParse, pSrc, pIdx, pFKey, aiCol, regNew, -1);
+ fkScanChildren(pParse, pSrc, pIdx, pFKey, aiCol, regNew, -1);
}
if( regOld!=0 ){
/* If there is a RESTRICT action configured for the current operation
- ** on the referenced table of this FK, then throw an exception
+ ** on the parent table of this FK, then throw an exception
** immediately if the FK constraint is violated, even if this is a
** deferred trigger. That's what RESTRICT means. To defer checking
** the constraint, the FK should specify NO ACTION (represented
** using OE_None). NO ACTION is the default. */
- fkScanReferences(pParse, pSrc, pIdx, pFKey, aiCol, regOld,
- (pChanges!=0 && pFKey->updateConf!=OE_Restrict)
- || (pChanges==0 && pFKey->deleteConf!=OE_Restrict)
+ fkScanChildren(pParse, pSrc, pIdx, pFKey, aiCol, regOld,
+ pFKey->aAction[pChanges!=0]!=OE_Restrict
);
}
@@ -619,8 +727,37 @@
return 0;
}
+/*
+** This function is called when an UPDATE or DELETE operation is being
+** compiled on table pTab, which is the parent table of foreign-key pFKey.
+** If the current operation is an UPDATE, then the pChanges parameter is
+** passed a pointer to the list of columns being modified. If it is a
+** DELETE, pChanges is passed a NULL pointer.
+**
+** It returns a pointer to a Trigger structure containing a trigger
+** equivalent to the ON UPDATE or ON DELETE action specified by pFKey.
+** If the action is "NO ACTION" or "RESTRICT", then a NULL pointer is
+** returned (these actions require no special handling by the triggers
+** sub-system, code for them is created by fkScanChildren()).
+**
+** For example, if pFKey is the foreign key and pTab is table "p" in
+** the following schema:
+**
+** CREATE TABLE p(pk PRIMARY KEY);
+** CREATE TABLE c(ck REFERENCES p ON DELETE CASCADE);
+**
+** then the returned trigger structure is equivalent to:
+**
+** CREATE TRIGGER ... DELETE ON p BEGIN
+** DELETE FROM c WHERE ck = old.pk;
+** END;
+**
+** The returned pointer is cached as part of the foreign key object. It
+** is eventually freed along with the rest of the foreign key object by
+** sqlite3FkDelete().
+*/
static Trigger *fkActionTrigger(
- Parse *pParse,
+ Parse *pParse, /* Parse context */
Table *pTab, /* Table being updated or deleted from */
FKey *pFKey, /* Foreign key to get action for */
ExprList *pChanges /* Change-list for UPDATE, NULL for DELETE */
@@ -628,21 +765,17 @@
sqlite3 *db = pParse->db; /* Database handle */
int action; /* One of OE_None, OE_Cascade etc. */
Trigger *pTrigger; /* Trigger definition to return */
+ int iAction = (pChanges!=0); /* 1 for UPDATE, 0 for DELETE */
- if( pChanges ){
- action = pFKey->updateConf;
- pTrigger = pFKey->pOnUpdate;
- }else{
- action = pFKey->deleteConf;
- pTrigger = pFKey->pOnDelete;
- }
+ action = pFKey->aAction[iAction];
+ pTrigger = pFKey->apTrigger[iAction];
assert( OE_SetNull>OE_Restrict && OE_SetDflt>OE_Restrict );
assert( OE_Cascade>OE_Restrict && OE_None<OE_Restrict );
if( action>OE_Restrict && !pTrigger ){
u8 enableLookaside; /* Copy of db->lookaside.bEnabled */
- char const *zFrom; /* Name of referencing table */
+ char const *zFrom; /* Name of child table */
int nFrom; /* Length in bytes of zFrom */
Index *pIdx = 0; /* Parent key index for this FK */
int *aiCol = 0; /* child table cols -> parent key cols */
@@ -658,9 +791,9 @@
for(i=0; i<pFKey->nCol; i++){
Token tOld = { "old", 3 }; /* Literal "old" token */
Token tNew = { "new", 3 }; /* Literal "new" token */
- Token tFromCol; /* Name of column in referencing table */
- Token tToCol; /* Name of column in referenced table */
- int iFromCol; /* Idx of column in referencing table */
+ Token tFromCol; /* Name of column in child table */
+ Token tToCol; /* Name of column in parent table */
+ int iFromCol; /* Idx of column in child table */
Expr *pEq; /* tFromCol = OLD.tToCol */
iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
@@ -766,16 +899,8 @@
pStep->pTrig = pTrigger;
pTrigger->pSchema = pTab->pSchema;
pTrigger->pTabSchema = pTab->pSchema;
-
- if( pChanges ){
- pFKey->pOnUpdate = pTrigger;
- pTrigger->op = TK_UPDATE;
- pStep->op = TK_UPDATE;
- }else{
- pFKey->pOnDelete = pTrigger;
- pTrigger->op = TK_DELETE;
- pStep->op = (action==OE_Cascade)?TK_DELETE:TK_UPDATE;
- }
+ pFKey->apTrigger[iAction] = pTrigger;
+ pTrigger->op = (pChanges ? TK_UPDATE : TK_DELETE);
}
return pTrigger;
@@ -833,8 +958,8 @@
/* Delete any triggers created to implement actions for this FK. */
#ifndef SQLITE_OMIT_TRIGGER
- fkTriggerDelete(pTab->dbMem, pFKey->pOnDelete);
- fkTriggerDelete(pTab->dbMem, pFKey->pOnUpdate);
+ fkTriggerDelete(pTab->dbMem, pFKey->apTrigger[0]);
+ fkTriggerDelete(pTab->dbMem, pFKey->apTrigger[1]);
#endif
/* Delete the memory allocated for the FK structure. */
diff --git a/src/parse.y b/src/parse.y
index 8fe4ef0..32dedfe 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -314,7 +314,7 @@
// check fails.
//
%type refargs {int}
-refargs(A) ::= . { A = OE_None * 0x010101; }
+refargs(A) ::= . { A = OE_None * 0x000101; }
refargs(A) ::= refargs(X) refarg(Y). { A = (X & ~Y.mask) | Y.value; }
%type refarg {struct {int value; int mask;}}
refarg(A) ::= MATCH nm. { A.value = 0; A.mask = 0x000000; }
diff --git a/src/pragma.c b/src/pragma.c
index d933735..3d779a7 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -981,8 +981,8 @@
int j;
for(j=0; j<pFK->nCol; j++){
char *zCol = pFK->aCol[j].zCol;
- char *zOnUpdate = (char *)actionName(pFK->updateConf);
- char *zOnDelete = (char *)actionName(pFK->deleteConf);
+ char *zOnDelete = (char *)actionName(pFK->aAction[0]);
+ char *zOnUpdate = (char *)actionName(pFK->aAction[1]);
sqlite3VdbeAddOp2(v, OP_Integer, i, 1);
sqlite3VdbeAddOp2(v, OP_Integer, j, 2);
sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, pFK->zTo, 0);
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 17aed29..b028efe 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1290,11 +1290,8 @@
FKey *pPrevTo; /* Previous foreign key on table named zTo */
int nCol; /* Number of columns in this key */
u8 isDeferred; /* True if constraint checking is deferred till COMMIT */
- u8 updateConf; /* How to resolve conflicts that occur on UPDATE */
- u8 deleteConf; /* How to resolve conflicts that occur on DELETE */
- u8 insertConf; /* How to resolve conflicts that occur on INSERT */
- Trigger *pOnUpdate; /* Trigger for AFTER UPDATE ON zTo */
- Trigger *pOnDelete; /* Trigger for AFTER DELETE ON zTo */
+ u8 aAction[2]; /* ON DELETE and ON UPDATE actions, respectively */
+ Trigger *apTrigger[2]; /* Triggers for aAction[] actions */
struct sColMap { /* Mapping of columns in pFrom to columns in zTo */
int iFrom; /* Index of column in pFrom */
char *zCol; /* Name of column in zTo. If 0 use PRIMARY KEY */