FETCH from CURSOR inside a function should be disabled without a dest…

…ination (#2411) SELECT statements included within a function cannot return data to a client. This operation was not blocked with the FETCH CURSOR operation. This commit aim to restrict defining such function. Issues Resolved: BABEL-4584 Signed-off-by: Shard Gupta <[email protected]>
babelfish-for-postgresql · Apr 17, 2024 · f129c68 · f129c68
1 parent fdb469e
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Showing 3 changed files with 249 additions and 2 deletions.
diff --git a/contrib/babelfishpg_tsql/src/tsqlIface.cpp b/contrib/babelfishpg_tsql/src/tsqlIface.cpp
@@ -4777,6 +4777,12 @@ makeFetchCurosrStatement(TSqlParser::Fetch_cursorContext *ctx)
 	auto targetText = ::getFullText(ctx->cursor_name());
 	result->curvar = lookup_cursor_variable(targetText.c_str())->dno;
 
+	/* FETCH CURSOR without destination should be blocked inside a function. */
+
+	if (is_compiling_create_function() && !ctx->INTO())
+	{
+		throw PGErrorWrapperException(ERROR, ERRCODE_INVALID_FUNCTION_DEFINITION, "SELECT statements included within a function cannot return data to a client.", getLineAndPos(ctx));
+	}
 	/* fetch option */
 	if (ctx->NEXT()) {
 		result->direction = FETCH_FORWARD;

diff --git a/test/JDBC/expected/BABEL-2218.out b/test/JDBC/expected/BABEL-2218.out
@@ -3,9 +3,12 @@ go
 
 CREATE TABLE t2218(c1 INT)
 INSERT INTO t2218 VALUES (2218);
+INSERT INTO t2218 VALUES (2219);
 GO
 ~~ROW COUNT: 1~~
 
+~~ROW COUNT: 1~~
+
 
 -- should throw an error
 CREATE FUNCTION f2218()
@@ -42,10 +45,136 @@ DECLARE @ret INT;
 SET @ret = f2218();
 SELECT @ret;
 DROP FUNCTION f2218;
-DROP TABLE t2218;
+GO
+~~START~~
+int
+2219
+~~END~~
+
+
+-- Throw error if cursor for select doesn't have a destination(INTO @variable) inside a function BABEL-4586
+CREATE FUNCTION f_getval()RETURNS INTEGER
+AS
+BEGIN
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor
+  CLOSE temp_cursor
+  RETURN 1
+END
+go
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: SELECT statements included within a function cannot return data to a client.)~~
+
+
+-- cursor for select work if the destination(INTO @variable) is provided inside a function BABEL-4586
+CREATE FUNCTION f_getval() RETURNS INTEGER
+AS
+BEGIN
+  DECLARE @my_var int
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+  RETURN @my_var
+END
+go
+
+DROP FUNCTION f_getval;
+GO
+
+-- cursor for select work with multiple fetch if the destination(INTO @variable) is provided inside a function BABEL-4586
+CREATE FUNCTION f_getval() RETURNS INTEGER
+AS
+BEGIN
+  DECLARE @my_var int
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+  RETURN @my_var
+END
+go
+
+DROP FUNCTION f_getval;
+GO
+
+-- cursor for select should throw error even if one fetch tries to return results to client
+CREATE FUNCTION f_getval() RETURNS INTEGER
+AS
+BEGIN
+  DECLARE @my_var int
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  FETCH NEXT FROM temp_cursor
+  CLOSE temp_cursor
+  RETURN @my_var
+END
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: SELECT statements included within a function cannot return data to a client.)~~
+
+
+-- cursor for select should work for procedure
+CREATE PROCEDURE proc_with_cursor_fetch
+AS
+BEGIN
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor
+  CLOSE temp_cursor
+END
+GO
+
+DROP PROCEDURE proc_with_cursor_fetch;
+GO
+
+-- cursor for select should work for procedure with INTO
+CREATE PROCEDURE proc_with_cursor_fetch
+AS
+BEGIN
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  DECLARE @my_var int
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+END
+GO
+
+DROP PROCEDURE proc_with_cursor_fetch;
+GO
+
+CREATE TRIGGER trg1 ON t2218 AFTER INSERT AS
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  DECLARE @my_var int
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+GO
+
+CREATE TRIGGER trg2 ON t2218 AFTER INSERT AS
+  DECLARE temp_cursor1 CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor1
+  FETCH NEXT FROM temp_cursor1
+  CLOSE temp_cursor1
+GO
+
+-- Trigger after insert
+INSERT INTO t2218 VALUES (2218);
 GO
 ~~START~~
 int
 2218
 ~~END~~
 
+~~ROW COUNT: 1~~
+
+
+DROP TRIGGER trg1
+DROP TRIGGER trg2
+DROP TABLE t2218
+GO
diff --git a/test/JDBC/input/BABEL-2218.sql b/test/JDBC/input/BABEL-2218.sql
@@ -3,6 +3,7 @@ go
 
 CREATE TABLE t2218(c1 INT)
 INSERT INTO t2218 VALUES (2218);
+INSERT INTO t2218 VALUES (2219);
 GO
 
 -- should throw an error
@@ -36,5 +37,116 @@ SET @ret = f2218();
 SELECT @ret;
 
 DROP FUNCTION f2218;
-DROP TABLE t2218;
+GO
+
+-- Throw error if cursor for select doesn't have a destination(INTO @variable) inside a function BABEL-4586
+CREATE FUNCTION f_getval()RETURNS INTEGER
+AS
+BEGIN
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor
+  CLOSE temp_cursor
+  RETURN 1
+END
+go
+
+-- cursor for select work if the destination(INTO @variable) is provided inside a function BABEL-4586
+CREATE FUNCTION f_getval() RETURNS INTEGER
+AS
+BEGIN
+  DECLARE @my_var int
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+  RETURN @my_var
+END
+go
+
+DROP FUNCTION f_getval;
+GO
+
+-- cursor for select work with multiple fetch if the destination(INTO @variable) is provided inside a function BABEL-4586
+CREATE FUNCTION f_getval() RETURNS INTEGER
+AS
+BEGIN
+  DECLARE @my_var int
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+  RETURN @my_var
+END
+go
+
+DROP FUNCTION f_getval;
+GO
+
+-- cursor for select should throw error even if one fetch tries to return results to client
+CREATE FUNCTION f_getval() RETURNS INTEGER
+AS
+BEGIN
+  DECLARE @my_var int
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  FETCH NEXT FROM temp_cursor
+  CLOSE temp_cursor
+  RETURN @my_var
+END
+GO
+
+-- cursor for select should work for procedure
+CREATE PROCEDURE proc_with_cursor_fetch
+AS
+BEGIN
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor
+  CLOSE temp_cursor
+END
+GO
+
+DROP PROCEDURE proc_with_cursor_fetch;
+GO
+
+-- cursor for select should work for procedure with INTO
+CREATE PROCEDURE proc_with_cursor_fetch
+AS
+BEGIN
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  DECLARE @my_var int
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+END
+GO
+
+DROP PROCEDURE proc_with_cursor_fetch;
+GO
+
+CREATE TRIGGER trg1 ON t2218 AFTER INSERT AS
+  DECLARE temp_cursor CURSOR FOR SELECT c1 FROM t2218
+  DECLARE @my_var int
+  OPEN temp_cursor
+  FETCH NEXT FROM temp_cursor INTO @my_var
+  CLOSE temp_cursor
+GO
+
+CREATE TRIGGER trg2 ON t2218 AFTER INSERT AS
+  DECLARE temp_cursor1 CURSOR FOR SELECT c1 FROM t2218
+  OPEN temp_cursor1
+  FETCH NEXT FROM temp_cursor1
+  CLOSE temp_cursor1
+GO
+
+-- Trigger after insert
+INSERT INTO t2218 VALUES (2218);
+GO
+
+DROP TRIGGER trg1
+DROP TRIGGER trg2
+DROP TABLE t2218
 GO