diff --git a/Document/PG增加列.txt b/Document/PG增加列.txt
index 6bc5f357..ae377a8a 100644
--- a/Document/PG增加列.txt
+++ b/Document/PG增加列.txt
@@ -14,4 +14,14 @@ where  relkind = 'r' and relname like 'j%_r' and relname not like 'pg_%' and rel
 
 
 -- 删除默认值
-ALTER TABLE table_name ALTER COLUMN column_name DROP DEFAULT;
\ No newline at end of file
+ALTER TABLE table_name ALTER COLUMN column_name DROP DEFAULT;
+
+
+select 'alter table '||pg_class.relname || ' drop constraint '|| pg_constraint.conname ||';' as pk_name from 
+pg_constraint  inner join pg_class 
+on pg_constraint.conrelid = pg_class.oid 
+inner join pg_attribute on pg_attribute.attrelid = pg_class.oid 
+and  pg_attribute.attnum = pg_constraint.conkey[1]
+inner join pg_type on pg_type.oid = pg_attribute.atttypid where pg_attribute.attname='rowid'
+-- where pg_class.relname = 'teacher' 
+and pg_constraint.contype='p'