When adding a new column to a table, include a primary key if the field is either a primary key itself or has an auto-increment attribute (#129)

* When adding a new column to a table, include a primary key if the field is either a primary key itself or has an auto-increment attribute.

* When adding a new column to a table, include a primary key if the field is either a primary key itself or has an auto-increment attribute.

---------

Co-authored-by: Ganesan Karuppasamy <ganesan.karuppasamy@sap.com>

Author: ckganesan

go.sum

@@ -7,4 +7,4 @@ github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/
 gorm.io/gorm v1.25.1 h1:nsSALe5Pr+cM3V1qwwQ7rOkw+6UeLrX5O4v3llhHa64=
 gorm.io/gorm v1.25.1/go.mod h1:L4uxeKpfBml98NYqVqwAdmV1a2nBtAec/cf3fpucW/k=
 gorm.io/gorm v1.25.2-0.20230530020048-26663ab9bf55 h1:sC1Xj4TYrLqg1n3AN10w871An7wJM0gzgcm8jkIkECQ=
-gorm.io/gorm v1.25.2-0.20230530020048-26663ab9bf55/go.mod h1:L4uxeKpfBml98NYqVqwAdmV1a2nBtAec/cf3fpucW/k=
+gorm.io/gorm v1.25.2-0.20230530020048-26663ab9bf55/go.mod h1:L4uxeKpfBml98NYqVqwAdmV1a2nBtAec/cf3fpucW/k=

migrator.go

@@ -47,6 +47,31 @@ func (m Migrator) FullDataTypeOf(field *schema.Field) clause.Expr {
 	return expr
 }
 
+func (m Migrator) AddColumn(value interface{}, name string) error {
+	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
+		// avoid using the same name field
+		f := stmt.Schema.LookUpField(name)
+		if f == nil {
+			return fmt.Errorf("failed to look up field with name: %s", name)
+		}
+
+		if !f.IgnoreMigration {
+			fieldType := m.FullDataTypeOf(f)
+			columnName := clause.Column{Name: f.DBName}
+			values := []interface{}{m.CurrentTable(stmt), columnName, fieldType}
+			var alterSql strings.Builder
+			alterSql.WriteString("ALTER TABLE ? ADD ? ?")
+			if f.PrimaryKey || strings.Contains(strings.ToLower(fieldType.SQL), "auto_increment") {
+				alterSql.WriteString(", ADD PRIMARY KEY (?)")
+				values = append(values, columnName)
+			}
+			return m.DB.Exec(alterSql.String(), values...).Error
+		}
+
+		return nil
+	})
+}
+
 func (m Migrator) AlterColumn(value interface{}, field string) error {
 	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
 		if stmt.Schema != nil {