Add comments and prototype for experimental sqlite_last_statement_changes() API function. Also, allow function to be called from tcl. (CVS 1273)

FossilOrigin-Name: ca99920b0dbf773962b47766d690154fd1276513

4 files changed, 77 insertions, 14 deletions

diff --git a/src/func.c b/src/func.c
index fd581f8a1..e6613c5b1 100644
--- a/src/func.c
+++ b/src/func.c
@@ -16,7 +16,7 @@
 ** sqliteRegisterBuildinFunctions() found at the bottom of the file.
 ** All other code has file scope.
 **
-** $Id: func.c,v 1.42 2004/02/25 13:47:32 drh Exp $
+** $Id: func.c,v 1.43 2004/02/25 22:51:06 rdc Exp $
 */
 #include <ctype.h>
 #include <math.h>
@@ -210,10 +210,19 @@ static void last_insert_rowid(sqlite_func *context, int arg, const char **argv){
   sqlite_set_result_int(context, sqlite_last_insert_rowid(db));
 }
 
+/*
+** Implementation of the change_count() SQL function.  The return
+** value is the same as the sqlite_changes() API function.
+*/
 static void change_count(sqlite_func *context, int arg, const char **argv){
   sqlite *db = sqlite_user_data(context);
   sqlite_set_result_int(context, sqlite_changes(db));
 }
+
+/*
+** Implementation of the last_statement_change_count() SQL function.  The
+** return value is the same as the sqlite_last_statement_changes() API function.
+*/
 static void last_statement_change_count(sqlite_func *context, int arg,
                                         const char **argv){
   sqlite *db = sqlite_user_data(context);
diff --git a/src/main.c b/src/main.c
index ea1e6df8b..c299c2c30 100644
--- a/src/main.c
+++ b/src/main.c
@@ -14,7 +14,7 @@
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
 **
-** $Id: main.c,v 1.160 2004/02/25 13:47:32 drh Exp $
+** $Id: main.c,v 1.161 2004/02/25 22:51:06 rdc Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -545,6 +545,12 @@ int sqlite_changes(sqlite *db){
   return db->nChange;
 }
 
+/*
+** Return the number of changes produced by the last INSERT, UPDATE, or
+** DELETE statement to complete execution. The count does not include
+** changes due to SQL statements executed in trigger programs that were
+** triggered by that statement
+*/
 int sqlite_last_statement_changes(sqlite *db){
   return db->lsChange;
 }
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 32c3ba8ab..fa45d7d97 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -12,7 +12,7 @@
 ** This header file defines the interface that the SQLite library
 ** presents to client programs.
 **
-** @(#) $Id: sqlite.h.in,v 1.58 2004/02/25 13:47:33 drh Exp $
+** @(#) $Id: sqlite.h.in,v 1.59 2004/02/25 22:51:06 rdc Exp $
 */
 #ifndef _SQLITE_H_
 #define _SQLITE_H_
@@ -204,6 +204,32 @@ int sqlite_last_insert_rowid(sqlite*);
 */
 int sqlite_changes(sqlite*);
 
+/*
+** This function returns the number of database rows that were changed
+** by the last INSERT, UPDATE, or DELETE statment executed by sqlite_exec(),
+** or by the last VM to run to completion. The change count is not updated
+** by SQL statements other than INSERT, UPDATE or DELETE.
+**
+** Changes are counted, even if they are later undone by a ROLLBACK or
+** ABORT. Changes associated with trigger programs that execute as a
+** result of the INSERT, UPDATE, or DELETE statement are not counted.
+**
+** If a callback invokes sqlite_exec() recursively, then the changes
+** in the inner, recursive call are counted together with the changes
+** in the outer call.
+**
+** SQLite implements the command "DELETE FROM table" without a WHERE clause
+** by dropping and recreating the table.  (This is much faster than going
+** through and deleting individual elements form the table.)  Because of
+** this optimization, the change count for "DELETE FROM table" will be
+** zero regardless of the number of elements that were originally in the
+** table. To get an accurate count of the number of rows deleted, use
+** "DELETE FROM table WHERE 1" instead.
+**
+******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
+*/
+int sqlite_last_statement_changes(sqlite*);
+
 /* If the parameter to this routine is one of the return value constants
 ** defined above, then this routine returns a constant text string which
 ** descripts (in English) the meaning of the return value.
diff --git a/src/tclsqlite.c b/src/tclsqlite.c
index 2ef5bfa9e..4e3976478 100644
--- a/src/tclsqlite.c
+++ b/src/tclsqlite.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** A TCL Interface to SQLite
 **
-** $Id: tclsqlite.c,v 1.58 2004/02/12 20:49:36 drh Exp $
+** $Id: tclsqlite.c,v 1.59 2004/02/25 22:51:06 rdc Exp $
 */
 #ifndef NO_TCL     /* Omit this whole file if TCL is unavailable */
 
@@ -488,19 +488,21 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
   int choice;
   int rc = TCL_OK;
   static const char *DB_strs[] = {
-    "authorizer",         "busy",              "changes",
-    "close",              "commit_hook",       "complete",
-    "errorcode",          "eval",              "function",
-    "last_insert_rowid",  "onecolumn",         "progress",
-    "rekey",              "timeout",           "trace",
+    "authorizer",         "busy",                   "changes",
+    "close",              "commit_hook",            "complete",
+    "errorcode",          "eval",                   "function",
+    "last_insert_rowid",  "last_statement_changes", "onecolumn",
+    "progress",           "rekey",                  "timeout",
+    "trace",
     0                    
   };
   enum DB_enum {
-    DB_AUTHORIZER,        DB_BUSY,             DB_CHANGES,
-    DB_CLOSE,             DB_COMMIT_HOOK,      DB_COMPLETE,
-    DB_ERRORCODE,         DB_EVAL,             DB_FUNCTION,
-    DB_LAST_INSERT_ROWID, DB_ONECOLUMN,        DB_PROGRESS,
-    DB_REKEY,             DB_TIMEOUT,          DB_TRACE,
+    DB_AUTHORIZER,        DB_BUSY,                   DB_CHANGES,
+    DB_CLOSE,             DB_COMMIT_HOOK,            DB_COMPLETE,
+    DB_ERRORCODE,         DB_EVAL,                   DB_FUNCTION,
+    DB_LAST_INSERT_ROWID, DB_LAST_STATEMENT_CHANGES, DB_ONECOLUMN,        
+    DB_PROGRESS,          DB_REKEY,                  DB_TIMEOUT,
+    DB_TRACE
   };
 
   if( objc<2 ){
@@ -660,6 +662,26 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
     break;
   }
 
+  /*
+  **     $db last_statement_changes
+  **
+  ** Return the number of rows that were modified, inserted, or deleted by
+  ** the last statment to complete execution (excluding changes due to
+  ** triggers)
+  */
+  case DB_LAST_STATEMENT_CHANGES: {
+    Tcl_Obj *pResult;
+    int lsChange;
+    if( objc!=2 ){
+      Tcl_WrongNumArgs(interp, 2, objv, "");
+      return TCL_ERROR;
+    }
+    lsChange = sqlite_last_statement_changes(pDb->db);
+    pResult = Tcl_GetObjResult(interp);
+    Tcl_SetIntObj(pResult, lsChange);
+    break;
+  }
+
   /*    $db close
   **
   ** Shutdown the database