Extract dependency on View and Table from View

README.md

@@ -76,3 +76,7 @@ CREATE INDEX Test_Name_CreatedAt ON Test(Name, CreatedAt DESC);
 $ gcloud spanner databases ddl update test --ddl-file=tmp.sql
 Schema updating...done.
 ```
+
+## Known Issues & Limitations
+
+- View DDL generation may be incorrect or out of order due to unresolved column names in the view query.

definition.go

@@ -863,11 +863,37 @@ func (v *view) alter(tgt definition, m *migration) {
 }
 
 func (v *view) dependsOn() []identifier {
-	// TODO: process query to find dependencies
-	return nil
+	var ids []identifier
+	paths, idents := tablesOrViewsInQueryExpr(v.node.Query)
+	// Can't distinguish between tables and views, so add both.
+	for _, ident := range idents {
+		ids = append(ids,
+			newTableIDFromIdent(ident),
+			newViewIDFromIdent(ident),
+		)
+	}
+	for _, path := range paths {
+		ids = append(ids,
+			newTableIDFromPath(path),
+			newViewIDFromPath(path),
+		)
+	}
+	// TODO: Add dependencies on columns.
+	// But it's difficult to extract column names from the query!
+	return ids
 }
 
-func (v *view) onDependencyChange(me, dependency migrationState, m *migration) {}
+func (v *view) onDependencyChange(me, dependency migrationState, m *migration) {
+	switch dep := dependency.definition().(type) {
+	case *column, *table, *view:
+		switch dependency.kind {
+		case migrationKindDropAndAdd:
+			m.updateState(me.updateKind(migrationKindDropAndAdd))
+		}
+	default:
+		panic(fmt.Sprintf("unexpected dependOn type on view: %T", dep))
+	}
+}
 
 type changeStream struct {
 	node *ast.CreateChangeStream

spannerdiff_test.go

@@ -530,6 +530,26 @@ func TestDiff(t *testing.T) {
 			CREATE OR REPLACE VIEW V1 SQL SECURITY DEFINER AS SELECT * FROM T1 WHERE T1_I1 > 0;`,
 			false,
 		},
+		"drop and create view": {
+			`
+			CREATE TABLE T1 (
+			  T1_I1 INT64 NOT NULL,
+			) PRIMARY KEY(T1_I1);
+			CREATE VIEW V1 SQL SECURITY DEFINER AS SELECT * FROM T1;`,
+			`
+			CREATE TABLE T1 (
+			  T1_S1 STRING(MAX) NOT NULL,
+			) PRIMARY KEY(T1_S1);
+			CREATE VIEW V1 SQL SECURITY DEFINER AS SELECT * FROM T1;`,
+			`
+			DROP VIEW V1;
+			DROP TABLE T1;
+			CREATE TABLE T1 (
+			  T1_S1 STRING(MAX) NOT NULL,
+			) PRIMARY KEY(T1_S1);
+			CREATE VIEW V1 SQL SECURITY DEFINER AS SELECT * FROM T1;`,
+			false,
+		},
 		"add change stream": {
 			``,
 			`
@@ -772,6 +792,16 @@ func TestDiff(t *testing.T) {
 			ALTER DATABASE D1 SET OPTIONS (version_retention_period = '2d');`,
 			false,
 		},
+		"issue #35": {
+			``,
+			`
+			CREATE OR REPLACE VIEW V2 SQL SECURITY INVOKER AS SELECT * FROM T1;
+			CREATE OR REPLACE VIEW V1 SQL SECURITY INVOKER AS SELECT * FROM V2;`,
+			`
+			CREATE OR REPLACE VIEW V2 SQL SECURITY INVOKER AS SELECT * FROM T1;
+			CREATE OR REPLACE VIEW V1 SQL SECURITY INVOKER AS SELECT * FROM V2;`,
+			false,
+		},
 	} {
 		t.Run(name, func(t *testing.T) {
 			var buf bytes.Buffer

util.go

@@ -156,3 +156,19 @@ func uniqueIdent(is []*ast.Ident) []*ast.Ident {
 		return i.Name
 	})
 }
+
+func tablesOrViewsInQueryExpr(expr ast.QueryExpr) ([]*ast.Path, []*ast.Ident) {
+	var idents []*ast.Ident
+	var paths []*ast.Path
+
+	ast.Inspect(expr, func(n ast.Node) bool {
+		switch t := n.(type) {
+		case *ast.TableName:
+			idents = append(idents, t.Table)
+		case *ast.PathTableExpr:
+			paths = append(paths, t.Path)
+		}
+		return true
+	})
+	return paths, idents
+}