diff --git a/db_go18.go b/context.go
similarity index 99%
rename from db_go18.go
rename to context.go
index 72cb390..e24f103 100644
--- a/db_go18.go
+++ b/context.go
@@ -1,5 +1,3 @@
-//go:build go1.8
-
 package txdb
 
 import (
diff --git a/db.go b/db.go
index bd08198..e561b97 100644
--- a/db.go
+++ b/db.go
@@ -367,6 +367,20 @@ func (c *conn) Query(query string, args []driver.Value) (driver.Rows, error) {
 	return buildRows(rs)
 }
 
+// Implement the NamedValueChecker interface
+func (c *conn) CheckNamedValue(nv *driver.NamedValue) error {
+	if nvc, ok := c.drv.realConn.(driver.NamedValueChecker); ok {
+		return nvc.CheckNamedValue(nv)
+	}
+
+	switch nv.Value.(type) {
+	case sql.Out:
+		return nil
+	default:
+		return driver.ErrSkip
+	}
+}
+
 type stmt struct {
 	mu   sync.Mutex
 	st   *sql.Stmt
diff --git a/db_before_go18.go b/db_before_go18.go
deleted file mode 100644
index 291e240..0000000
--- a/db_before_go18.go
+++ /dev/null
@@ -1,14 +0,0 @@
-// +build !go1.8
-
-package txdb
-
-import (
-	"database/sql"
-	"database/sql/driver"
-)
-
-func buildRows(r *sql.Rows) (driver.Rows, error) {
-	rows := &rows{}
-	err := rows.read(r)
-	return rows, err
-}
diff --git a/db_go19.go b/db_go19.go
deleted file mode 100644
index 3c2f529..0000000
--- a/db_go19.go
+++ /dev/null
@@ -1,22 +0,0 @@
-// +build go1.9
-
-package txdb
-
-import (
-	"database/sql"
-	"database/sql/driver"
-)
-
-// Implement the NamedValueChecker interface
-func (c *conn) CheckNamedValue(nv *driver.NamedValue) error {
-	if nvc, ok := c.drv.realConn.(driver.NamedValueChecker); ok {
-		return nvc.CheckNamedValue(nv)
-	}
-
-	switch nv.Value.(type) {
-	case sql.Out:
-		return nil
-	default:
-		return driver.ErrSkip
-	}
-}