1 files changed, 47 insertions, 0 deletions
diff --git a/utils/custom_fields/custom_fields.sql b/utils/custom_fields/custom_fields.sql
new file mode 100644
index 00000000..0ee4290b
--- /dev/null
+++ b/utils/custom_fields/custom_fields.sql
@@ -0,0 +1,47 @@
+
+CREATE OR REPLACE FUNCTION add_custom_field (VARCHAR, VARCHAR, VARCHAR) 
+RETURNS BOOL AS
+'
+DECLARE
+table_name ALIAS FOR $1;
+new_field_name ALIAS FOR $2;
+field_datatype ALIAS FOR $3;
+
+BEGIN
+	EXECUTE ''SELECT TABLE_ID FROM custom_table_catalog 
+		WHERE extends = '''''' || table_name || '''''' '';
+	IF NOT FOUND THEN
+		BEGIN
+			INSERT INTO custom_table_catalog (extends) 
+				VALUES (table_name);
+			EXECUTE ''CREATE TABLE custom_''||table_name || 
+				'' (row_id INT)'';
+		EXCEPTION WHEN duplicate_table THEN
+			-- do nothing
+		END;
+	END IF;
+	EXECUTE ''INSERT INTO custom_field_catalog (field_name, table_id)
+	VALUES ( '''''' || new_field_name ||'''''', (SELECT table_id FROM custom_table_catalog
+		WHERE extends = ''''''|| table_name || ''''''))'';
+	EXECUTE ''ALTER TABLE custom_''||table_name || '' ADD COLUMN '' 
+		|| new_field_name || '' '' || field_datatype;
+	RETURN TRUE;
+END;
+' LANGUAGE PLPGSQL;
+
+CREATE OR REPLACE FUNCTION drop_custom_field (VARCHAR, VARCHAR) 
+RETURNS BOOL AS
+'
+DECLARE
+table_name ALIAS FOR $1;
+custom_field_name ALIAS FOR $2;
+BEGIN
+	DELETE FROM custom_field_catalog 
+	WHERE field_name = custom_field_name AND 
+		table_id = (SELECT table_id FROM custom_table_catalog 
+			WHERE extends = table_name);
+	EXECUTE ''ALTER TABLE custom_'' || table_name || 
+		'' DROP COLUMN '' || custom_field_name;
+	RETURN TRUE;	
+END;
+' LANGUAGE PLPGSQL;