Check in implementation of foreign key constraints.

FossilOrigin-Name: d5d399811876391642937edeb9e8434dd9e356f5

1 files changed, 23 insertions, 13 deletions

diff --git a/src/delete.c b/src/delete.c
index 7e5b7bfc4..a384ade73 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -308,7 +308,7 @@ void sqlite3DeleteFrom(
     goto delete_from_cleanup;
   }
   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
-  sqlite3BeginWriteOperation(pParse, (pTrigger?1:0), iDb);
+  sqlite3BeginWriteOperation(pParse, 1, iDb);
 
   /* If we are trying to delete from a view, realize that view into
   ** a ephemeral table.
@@ -341,7 +341,9 @@ void sqlite3DeleteFrom(
   ** It is easier just to erase the whole table. Prior to version 3.6.5,
   ** this optimization caused the row change count (the value returned by 
   ** API function sqlite3_count_changes) to be set incorrectly.  */
-  if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) ){
+  if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) 
+   && 0==sqlite3FkRequired(pParse, pTab, 0)
+  ){
     assert( !isView );
     sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt,
                       pTab->zName, P4_STATIC);
@@ -446,7 +448,7 @@ delete_from_cleanup:
 ** These are the requirements:
 **
 **   1.  A read/write cursor pointing to pTab, the table containing the row
-**       to be deleted, must be opened as cursor number "base".
+**       to be deleted, must be opened as cursor number $iCur.
 **
 **   2.  Read/write cursors for all indices of pTab must be open as
 **       cursor number base+i for the i-th index.
@@ -481,13 +483,13 @@ void sqlite3GenerateRowDelete(
  
   /* If there are any triggers to fire, allocate a range of registers to
   ** use for the old.* references in the triggers.  */
-  if( pTrigger ){
+  if( sqlite3FkRequired(pParse, pTab, 0) || pTrigger ){
     u32 mask;                     /* Mask of OLD.* columns in use */
     int iCol;                     /* Iterator used while populating OLD.* */
 
     /* TODO: Could use temporary registers here. Also could attempt to
     ** avoid copying the contents of the rowid register.  */
-    mask = sqlite3TriggerOldmask(pParse, pTrigger, TK_DELETE, 0, pTab, onconf);
+    mask = sqlite3TriggerOldmask(pParse, pTrigger, 0, pTab, onconf);
     iOld = pParse->nMem+1;
     pParse->nMem += (1 + pTab->nCol);
 
@@ -495,14 +497,14 @@ void sqlite3GenerateRowDelete(
     ** used by any BEFORE and AFTER triggers that exist.  */
     sqlite3VdbeAddOp2(v, OP_Copy, iRowid, iOld);
     for(iCol=0; iCol<pTab->nCol; iCol++){
-      if( mask==0xffffffff || mask&(1<<iCol) ){
+      if( 1 || mask==0xffffffff || mask&(1<<iCol) ){
         int iTarget = iOld + iCol + 1;
         sqlite3VdbeAddOp3(v, OP_Column, iCur, iCol, iTarget);
         sqlite3ColumnDefault(v, pTab, iCol, iTarget);
       }
     }
 
-    /* Invoke any BEFORE trigger programs */
+    /* Invoke BEFORE DELETE trigger programs. */
     sqlite3CodeRowTrigger(pParse, pTrigger, 
         TK_DELETE, 0, TRIGGER_BEFORE, pTab, -1, iOld, onconf, iLabel
     );
@@ -512,6 +514,11 @@ void sqlite3GenerateRowDelete(
     ** being deleted. Do not attempt to delete the row a second time, and 
     ** do not fire AFTER triggers.  */
     sqlite3VdbeAddOp3(v, OP_NotExists, iCur, iLabel, iRowid);
+
+    /* Do FK processing. This call checks that any FK constraints that
+    ** refer to this table (i.e. constraints attached to other tables) 
+    ** are not violated by deleting this row.  */
+    sqlite3FkCheck(pParse, pTab, 0, iOld, 0);
   }
 
   /* Delete the index and table entries. Skip this step if pTab is really
@@ -525,12 +532,15 @@ void sqlite3GenerateRowDelete(
     }
   }
 
-  /* Invoke AFTER triggers. */
-  if( pTrigger ){
-    sqlite3CodeRowTrigger(pParse, pTrigger, 
-        TK_DELETE, 0, TRIGGER_AFTER, pTab, -1, iOld, onconf, iLabel
-    );
-  }
+  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+  ** handle rows (possibly in other tables) that refer via a foreign key
+  ** to the row just deleted. */ 
+  sqlite3FkActions(pParse, pTab, 0, iOld);
+
+  /* Invoke AFTER DELETE trigger programs. */
+  sqlite3CodeRowTrigger(pParse, pTrigger, 
+      TK_DELETE, 0, TRIGGER_AFTER, pTab, -1, iOld, onconf, iLabel
+  );
 
   /* Jump here if the row had already been deleted before any BEFORE
   ** trigger programs were invoked. Or if a trigger program throws a