Update of /cvsroot/monetdb/pathfinder/compiler/sql
In directory sc8-pr-cvs16.sourceforge.net:/tmp/cvs-serv15976/compiler/sql
Modified Files:
lalg2sql.brg
Log Message:
-- Implemented sql-code-generation for algebra trees of the form
serialize_rel(empty_tbl).
Index: lalg2sql.brg
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/sql/lalg2sql.brg,v
retrieving revision 1.103
retrieving revision 1.104
diff -u -d -r1.103 -r1.104
--- lalg2sql.brg 14 Jan 2008 15:32:59 -0000 1.103
+++ lalg2sql.brg 14 Jan 2008 23:26:55 -0000 1.104
@@ -195,6 +195,7 @@
roots_ (twig (Twig))) = 5 (10);
Query: serialize_seq (Frag, empty_tbl) = 6 (10);
Query: serialize_rel (Rel) = 7 (10);
+Query: serialize_rel (empty_tbl) = 8 (10);
Rel: lit_tbl = 9 (10);
Rel: ref_tbl = 10 (10);
Rel: attach (Rel) = 11 (10);
@@ -2258,6 +2259,40 @@
}
break;
+ /* Query: serialize_rel(empty_tbl) */
+ case 8:
+ {
+ /*
+ Let's generate a pseudo-query whose result is an empty table:
+
+ SELECT -1 AS iter, -1 AS pos
+ FROM sysibm.sysdummy1 AS a0000
+ WHERE 1 = 0;
+ */
+
+
+ /* call a helper function that does the 'real' job */
+ PFsql_t* final_query = PFsql_select (
+ false,
+ select_list (
+ column_assign (lit_int (-1), ITER_),
+ column_assign (lit_int (-1), POS_)),
+ from_list(
+ alias_bind (
+ schema_table_name (
+ "sysibm",
+ table_name (PF_SQL_TABLE_SYSDUMMY1)),
+ alias (new_alias ()))),
+ where_list (
+ eq (lit_int (1), lit_int (0))),
+ NULL,
+ NULL);
+
+
+ sql_stmts = root (nil (), final_query);
+ }
+ break;
+
/* Rel: lit_tbl */
case 9:
if (p->sem.lit_tbl.count == 1) {
-------------------------------------------------------------------------
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