create index in hooks (#5)

adapter.go

@@ -66,7 +66,7 @@ func NewAdapter(driverName, dataSourceName string, opts ...adapterOption) (*bunA
 		b.db.AddQueryHook(bundebug.NewQueryHook(bundebug.WithVerbose(true)))
 	}
 
-	if err := b.createTalbe(); err != nil {
+	if err := b.createTable(); err != nil {
 		return nil, err
 	}
 
@@ -113,33 +113,26 @@ func connectDB(driverName, dataSourceName string) (*bun.DB, error) {
 	}
 }
 
-func (a *bunAdapter) createTalbe() error {
-	if err := a.db.RunInTx(context.Background(), &sql.TxOptions{}, func(ctx context.Context, tx bun.Tx) error {
-		if _, err := tx.NewCreateTable().
-			Model((*CasbinPolicy)(nil)).
-			ModelTableExpr(a.tableName).
-			IfNotExists().
-			Exec(ctx); err != nil {
-			return err
-		}
-		// it might be better to create a unique index using hooks
-		// but the table name(a.tableName) cannot be accessed from the hook
-		// so we create the index here
-		if _, err := tx.NewCreateIndex().
-			Model((*CasbinPolicy)(nil)).
-			ModelTableExpr(a.tableName).
-			IfNotExists().
-			Unique().
-			Index("idx_ptype_v0_v1_v2_v3_v4_v5").
-			Column("ptype", "v0", "v1", "v2", "v3", "v4", "v5").
-			Exec(ctx); err != nil {
-			return err
-		}
-		return nil
-	}); err != nil {
-		return err
-	}
-	return nil
+func (a *bunAdapter) createTable() error {
+	_, err := a.db.NewCreateTable().
+		Model((*CasbinPolicy)(nil)).
+		ModelTableExpr(a.tableName).
+		IfNotExists().
+		Exec(context.Background())
+	return err
+}
+
+var _ bun.AfterCreateTableHook = (*CasbinPolicy)(nil)
+
+func (*CasbinPolicy) AfterCreateTable(ctx context.Context, query *bun.CreateTableQuery) error {
+	_, err := query.DB().NewCreateIndex().
+		Model((*CasbinPolicy)(nil)).
+		ModelTableExpr(query.GetTableName()).
+		Unique().
+		Index("idx_ptype_v0_v1_v2_v3_v4_v5").
+		Column("ptype", "v0", "v1", "v2", "v3", "v4", "v5").
+		Exec(ctx)
+	return err
 }
 
 // LoadPolicy loads all policy rules from the storage.
@@ -225,7 +218,7 @@ func (a *bunAdapter) refreshTable() error {
 		Exec(context.Background()); err != nil {
 		return err
 	}
-	return a.createTalbe()
+	return a.createTable()
 }
 
 // AddPolicy adds a policy rule to the storage.