Fixed a bug in PostgreSQL when dropping NOT NULL constraints. (#133)

lib/SQL/Translator/Producer/PostgreSQL.pm

@@ -1058,6 +1058,11 @@ sub alter_drop_constraint {
     my ($c, $options) = @_;
     my $generator = _generator($options);
 
+    # NOT NULL constraint does not require a DROP CONSTRAINT statement
+    if ( $c->type eq NOT_NULL) {
+        return;
+    }
+
     # attention: Postgres  has a very special naming structure for naming
     # foreign keys and primary keys.  It names them using the name of the
     # table as prefix and fkey or pkey as suffix, concatenated by an underscore

t/30sqlt-new-diff-pgsql.t

@@ -78,6 +78,8 @@ ALTER TABLE "person" ALTER COLUMN "name" SET NOT NULL;
 
 ALTER TABLE "person" ALTER COLUMN "age" SET DEFAULT 18;
 
+ALTER TABLE "person" ALTER COLUMN "weight" DROP NOT NULL;
+
 ALTER TABLE "person" ALTER COLUMN "iq" TYPE bigint;
 
 ALTER TABLE "person" ALTER COLUMN "nickname" SET NOT NULL;
@@ -133,6 +135,8 @@ ALTER TABLE person ALTER COLUMN name SET NOT NULL;
 
 ALTER TABLE person ALTER COLUMN age SET DEFAULT 18;
 
+ALTER TABLE person ALTER COLUMN weight DROP NOT NULL;
+
 ALTER TABLE person ALTER COLUMN iq TYPE bigint;
 
 ALTER TABLE person ALTER COLUMN nickname SET NOT NULL;

t/data/diff/pgsql/create1.yml

@@ -135,6 +135,18 @@ schema:
           reference_fields: []
           reference_table: ''
           type: UNIQUE
+        - deferrable: 1
+          expression: ''
+          fields:
+            - weight
+          match_type: ''
+          name: ''
+          on_delete: ''
+          on_update: ''
+          options: []
+          reference_fields: []
+          reference_table: ''
+          type: NOT_NULL
       fields:
         age:
           data_type: int
@@ -194,7 +206,7 @@ schema:
           data_type: numeric
           default_value: ~
           extra: {}
-          is_nullable: 1
+          is_nullable: 0
           is_primary_key: 0
           is_unique: 0
           name: weight