feat: trigger old table

internal/diff/trigger.go

@@ -57,6 +57,14 @@ func triggersEqual(old, new *ir.Trigger) bool {
 		return false
 	}
 
+	// Compare transition table references
+	if old.OldTable != new.OldTable {
+		return false
+	}
+	if old.NewTable != new.NewTable {
+		return false
+	}
+
 	return true
 }
 
@@ -151,6 +159,19 @@ func generateTriggerSQLWithMode(trigger *ir.Trigger, targetSchema string) string
 	// Only include table name without schema if it's in the target schema
 	tableName := qualifyEntityName(trigger.Schema, trigger.Table, targetSchema)
 
+	// Build REFERENCING clause if present (for transition tables)
+	var referencingParts []string
+	if trigger.OldTable != "" {
+		referencingParts = append(referencingParts, fmt.Sprintf("OLD TABLE AS %s", trigger.OldTable))
+	}
+	if trigger.NewTable != "" {
+		referencingParts = append(referencingParts, fmt.Sprintf("NEW TABLE AS %s", trigger.NewTable))
+	}
+	referencingClause := ""
+	if len(referencingParts) > 0 {
+		referencingClause = fmt.Sprintf("\n    REFERENCING %s", strings.Join(referencingParts, " "))
+	}
+
 	// Build the trigger statement with proper formatting
 	// Use CREATE CONSTRAINT TRIGGER for constraint triggers (cannot use OR REPLACE)
 	var stmt string
@@ -167,10 +188,15 @@ func generateTriggerSQLWithMode(trigger *ir.Trigger, targetSchema string) string
 			}
 		}
 
+		// Add REFERENCING clause before FOR EACH
+		stmt += referencingClause
 		stmt += fmt.Sprintf("\n    FOR EACH %s", trigger.Level)
 	} else {
-		stmt = fmt.Sprintf("CREATE OR REPLACE TRIGGER %s\n    %s %s ON %s\n    FOR EACH %s",
-			trigger.Name, trigger.Timing, eventList, tableName, trigger.Level)
+		stmt = fmt.Sprintf("CREATE OR REPLACE TRIGGER %s\n    %s %s ON %s",
+			trigger.Name, trigger.Timing, eventList, tableName)
+		// Add REFERENCING clause before FOR EACH
+		stmt += referencingClause
+		stmt += fmt.Sprintf("\n    FOR EACH %s", trigger.Level)
 	}
 
 	// Add WHEN clause if present

ir/inspector.go

@@ -405,9 +405,14 @@ func (i *Inspector) buildConstraints(ctx context.Context, schema *IR, targetSche
 		if constraint.ConstraintType.Valid {
 			constraintType = constraint.ConstraintType.String
 		}
-		columnName := constraint.ColumnName
 
-		if columnName == "<nil>" {
+		// Extract column name from sql.NullString
+		columnName := ""
+		if constraint.ColumnName.Valid {
+			columnName = constraint.ColumnName.String
+		}
+
+		if columnName == "" || columnName == "<nil>" {
 			continue // Skip constraints without columns
 		}
 
@@ -1465,6 +1470,15 @@ func (i *Inspector) buildTriggers(ctx context.Context, schema *IR, targetSchema
 			for _, dbSchema := range parsedSchema.Schemas {
 				for _, parsedTable := range dbSchema.Tables {
 					for triggerName, trigger := range parsedTable.Triggers {
+						// Set transition table names from the system catalog query
+						// The parser extracts these from CREATE TRIGGER DDL, but for existing triggers
+						// we get the definitive values from pg_trigger catalog
+						if triggerRow.OldTable != "" {
+							trigger.OldTable = triggerRow.OldTable
+						}
+						if triggerRow.NewTable != "" {
+							trigger.NewTable = triggerRow.NewTable
+						}
 						table.Triggers[triggerName] = trigger
 					}
 				}

ir/ir.go

@@ -239,6 +239,8 @@ type Trigger struct {
 	IsConstraint      bool           `json:"is_constraint,omitempty"`       // Whether this is a constraint trigger
 	Deferrable        bool           `json:"deferrable,omitempty"`          // Can be deferred until end of transaction
 	InitiallyDeferred bool           `json:"initially_deferred,omitempty"`  // Whether deferred by default
+	OldTable          string         `json:"old_table,omitempty"`           // REFERENCING OLD TABLE AS name
+	NewTable          string         `json:"new_table,omitempty"`           // REFERENCING NEW TABLE AS name
 }
 
 // TriggerTiming represents the timing of trigger execution

ir/parser.go

@@ -3237,6 +3237,19 @@ func (p *Parser) parseCreateTrigger(triggerStmt *pg_query.CreateTrigStmt) error
 		condition = p.extractExpressionText(triggerStmt.WhenClause)
 	}
 
+	// Extract transition table references (REFERENCING OLD TABLE AS / NEW TABLE AS)
+	var oldTable, newTable string
+	for _, transRel := range triggerStmt.TransitionRels {
+		if rel := transRel.GetTriggerTransition(); rel != nil {
+			// rel.IsNew indicates if this is NEW TABLE (true) or OLD TABLE (false)
+			if rel.IsNew {
+				newTable = rel.Name
+			} else {
+				oldTable = rel.Name
+			}
+		}
+	}
+
 	// Create trigger
 	trigger := &Trigger{
 		Schema:            schemaName,
@@ -3250,6 +3263,8 @@ func (p *Parser) parseCreateTrigger(triggerStmt *pg_query.CreateTrigStmt) error
 		IsConstraint:      triggerStmt.Isconstraint,
 		Deferrable:        triggerStmt.Deferrable,
 		InitiallyDeferred: triggerStmt.Initdeferred,
+		OldTable:          oldTable,
+		NewTable:          newTable,
 	}
 
 	// Add trigger to table only

ir/queries/queries.sql

@@ -850,7 +850,9 @@ SELECT
     n.nspname AS trigger_schema,
     c.relname AS event_object_table,
     t.tgname AS trigger_name,
-    pg_catalog.pg_get_triggerdef(t.oid, false) AS trigger_definition
+    pg_catalog.pg_get_triggerdef(t.oid, false) AS trigger_definition,
+    COALESCE(t.tgoldtable, '') AS old_table,
+    COALESCE(t.tgnewtable, '') AS new_table
 FROM pg_catalog.pg_trigger t
 JOIN pg_catalog.pg_class c ON t.tgrelid = c.oid
 JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid

testdata/diff/create_trigger/add_trigger_old_table/diff.sql

@@ -0,0 +1,5 @@
+CREATE OR REPLACE TRIGGER orders_delete_trigger
+    AFTER DELETE ON orders
+    REFERENCING OLD TABLE AS old_orders
+    FOR EACH STATEMENT
+    EXECUTE FUNCTION archive_deleted_orders();

testdata/diff/create_trigger/add_trigger_old_table/new.sql

@@ -0,0 +1,25 @@
+CREATE TABLE public.orders (
+    id serial PRIMARY KEY,
+    amount numeric(10,2)
+);
+
+CREATE TABLE public.orders_archive (
+    id integer,
+    amount numeric(10,2),
+    deleted_at timestamp DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE OR REPLACE FUNCTION public.archive_deleted_orders()
+RETURNS trigger AS $$
+BEGIN
+    INSERT INTO orders_archive (id, amount)
+    SELECT id, amount FROM old_orders;
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER orders_delete_trigger
+    AFTER DELETE ON public.orders
+    REFERENCING OLD TABLE AS old_orders
+    FOR EACH STATEMENT
+    EXECUTE FUNCTION public.archive_deleted_orders();

testdata/diff/create_trigger/add_trigger_old_table/old.sql

@@ -0,0 +1,19 @@
+CREATE TABLE public.orders (
+    id serial PRIMARY KEY,
+    amount numeric(10,2)
+);
+
+CREATE TABLE public.orders_archive (
+    id integer,
+    amount numeric(10,2),
+    deleted_at timestamp DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE OR REPLACE FUNCTION public.archive_deleted_orders()
+RETURNS trigger AS $$
+BEGIN
+    INSERT INTO orders_archive (id, amount)
+    SELECT id, amount FROM old_orders;
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;

testdata/diff/create_trigger/add_trigger_old_table/plan.json

@@ -0,0 +1,20 @@
+{
+  "version": "1.0.0",
+  "pgschema_version": "1.2.1",
+  "created_at": "1970-01-01T00:00:00Z",
+  "source_fingerprint": {
+    "hash": "087a74a25f6a817a556750d274e732048ca5281379e6c0bedd1f5a35176daa2e"
+  },
+  "groups": [
+    {
+      "steps": [
+        {
+          "sql": "CREATE OR REPLACE TRIGGER orders_delete_trigger\n    AFTER DELETE ON orders\n    REFERENCING OLD TABLE AS old_orders\n    FOR EACH STATEMENT\n    EXECUTE FUNCTION archive_deleted_orders();",
+          "type": "table.trigger",
+          "operation": "create",
+          "path": "public.orders.orders_delete_trigger"
+        }
+      ]
+    }
+  ]
+}

testdata/diff/create_trigger/add_trigger_old_table/plan.sql

@@ -0,0 +1,5 @@
+CREATE OR REPLACE TRIGGER orders_delete_trigger
+    AFTER DELETE ON orders
+    REFERENCING OLD TABLE AS old_orders
+    FOR EACH STATEMENT
+    EXECUTE FUNCTION archive_deleted_orders();

testdata/diff/create_trigger/add_trigger_old_table/plan.txt

@@ -0,0 +1,17 @@
+Plan: 1 to modify.
+
+Summary by type:
+  tables: 1 to modify
+
+Tables:
+  ~ orders
+    + orders_delete_trigger (trigger)
+
+DDL to be executed:
+--------------------------------------------------
+
+CREATE OR REPLACE TRIGGER orders_delete_trigger
+    AFTER DELETE ON orders
+    REFERENCING OLD TABLE AS old_orders
+    FOR EACH STATEMENT
+    EXECUTE FUNCTION archive_deleted_orders();