Merge d65e8b3546b4c36dfa069c2890ec650099cfb631 into cde05781a05feb80def1aa46edac24a57ec93b30

README.md

@@ -84,6 +84,7 @@ type User struct{} // struct User's database table name is "users" by default, w
 * Use `CreatedAt` to store record's created time if field exists
 * Use `UpdatedAt` to store record's updated time if field exists
 * Use `DeletedAt` to store record's deleted time if field exists [Soft Delete](#soft-delete)
+* Use nullable `Alive` to store record's aliveness if field exists [Soft Delete](#soft-delete)
 * Gorm provide a default model struct, you could embed it in your struct
 
 ```go
@@ -446,10 +447,32 @@ db.Where("email LIKE ?", "%jinzhu%").Delete(Email{})
 //// DELETE from emails where email LIKE "%jinhu%";
 ```
 
-### Soft Delete
+### Soft-Delete
 
-If struct has `DeletedAt` field, it will get soft delete ability automatically!
+If a struct has a `DeletedAt` field, it will get soft-delete ability automatically!
-Then it won't be deleted from database permanently when call `Delete`.
+Then it won't be deleted from database permanently when `Delete()` is called.
+
+Or alternatively..
+
+If a struct has an `Alive` field it will get soft-delete ability automatically!
+Then it won't be deleted from the database permanently when `Delete()` is called.
+`Alive` will be set to `null`.  This makes it possible to still enforce unique
+constraints (e.g. "name", "alive"), but not have the unique constraint enforced
+for "deleted" records.
+
+```go
+type Friend struct {
+  ID    int64
+  Name  string `sql:"type:varchar(255)`
+  Alive int    `json:"-" sql:"type:integer;DEFAULT: 1;"`
+}
+
+db.Delete(&friend)
+//// UPDATE friends SET alive=null WHERE id = 42;
+```
+
+Note: Choose only one or the other.  It won't work right if both `DeletedAt` and
+`Alive` columns are defined.
 
 ```go
 db.Delete(&user)

callback_delete.go

@@ -8,13 +8,20 @@ func BeforeDelete(scope *Scope) {
 
 func Delete(scope *Scope) {
 	if !scope.HasError() {
-		if !scope.Search.Unscoped && scope.HasColumn("DeletedAt") {
+		unscoped := scope.Search.Unscoped
+		if !unscoped && scope.HasColumn("DeletedAt") {
 			scope.Raw(
 				fmt.Sprintf("UPDATE %v SET deleted_at=%v %v",
 					scope.QuotedTableName(),
 					scope.AddToVars(NowFunc()),
 					scope.CombinedConditionSql(),
 				))
+		} else if !unscoped && scope.HasColumn("Alive") {
+			scope.Raw(
+				fmt.Sprintf("UPDATE %v SET alive=null %v",
+					scope.QuotedTableName(),
+					scope.CombinedConditionSql(),
+				))
 		} else {
 			scope.Raw(fmt.Sprintf("DELETE FROM %v %v", scope.QuotedTableName(), scope.CombinedConditionSql()))
 		}

scope_private.go

@@ -158,9 +158,14 @@ func (scope *Scope) buildSelectQuery(clause map[string]interface{}) (str string)
 func (scope *Scope) whereSql() (sql string) {
 	var primaryConditions, andConditions, orConditions []string
 
-	if !scope.Search.Unscoped && scope.Fields()["deleted_at"] != nil {
+	if !scope.Search.Unscoped {
-		sql := fmt.Sprintf("(%v.deleted_at IS NULL OR %v.deleted_at <= '0001-01-02')", scope.QuotedTableName(), scope.QuotedTableName())
+		if scope.Fields()["deleted_at"] != nil {
-		primaryConditions = append(primaryConditions, sql)
+			sql := fmt.Sprintf("(%v.deleted_at IS NULL OR %v.deleted_at <= '0001-01-02')", scope.QuotedTableName(), scope.QuotedTableName())
+			primaryConditions = append(primaryConditions, sql)
+		} else if scope.Fields()["alive"] != nil {
+			sql := fmt.Sprintf("(%v.alive IS NOT NULL)", scope.QuotedTableName())
+			primaryConditions = append(primaryConditions, sql)
+		}
 	}
 
 	if !scope.PrimaryKeyZero() {