Allow empty string for default

Author: Sergey Podgornyy

README.md

@@ -41,8 +41,8 @@ var migrations = []migrator.Migration{
 			posts := migrator.Table{Name: "posts"}
 
 			posts.UniqueID("id")
-			posts.Column("title", migrator.String{Precision: 64})
-			posts.Column("content", migrator.Text{})
+			posts.Varchar("title", 64)
+			posts.Text("content", false)
 			posts.Timestamps()
 
 			s.CreateTable(posts)
@@ -65,8 +65,9 @@ var migrations = []migrator.Migration{
 
 			comments.UniqueID("id")
 			comments.UUID("post_id", "", false)
-			comments.Column("title", migrator.String{Precision: 64})
-			comments.Column("content", migrator.Text{})
+			comments.Varchar("name", 64)
+			comments.Column("email", migrator.String{Default: "<nil>"})
+			comments.Text("content", false)
 			comments.Timestamps()
 
 			comments.Foreign("post_id", "id", "posts", "RESTRICT", "RESTRICT")

column.go

@@ -549,5 +549,9 @@ func buildDefaultForString(v string) string {
 		return fmt.Sprintf(" DEFAULT %s", v)
 	}
 
+	if v == "<empty>" || v == "<nil>" {
+		v = ""
+	}
+
 	return fmt.Sprintf(" DEFAULT '%s'", v)
 }

column_test.go

@@ -578,6 +578,20 @@ func TestBuildDefaultForString(t *testing.T) {
 		assert.Equal(t, want, got)
 	})
 
+	t.Run("it builds default with empty string for <empty> value", func(t *testing.T) {
+		got := buildDefaultForString("<empty>")
+		want := " DEFAULT ''"
+
+		assert.Equal(t, want, got)
+	})
+
+	t.Run("it builds default with empty string for <nil> value", func(t *testing.T) {
+		got := buildDefaultForString("<nil>")
+		want := " DEFAULT ''"
+
+		assert.Equal(t, want, got)
+	})
+
 	t.Run("it builds normal default", func(t *testing.T) {
 		got := buildDefaultForString("value")
 		want := " DEFAULT 'value'"