From b1fd75fc953c2419425e08132143f56aa6687d31 Mon Sep 17 00:00:00 2001
From: Jerry <jerry@noreply.gitea.io>
Date: Sun, 11 Oct 2020 23:35:15 +0800
Subject: [PATCH] add tag on_update

---
 dialects/dialect.go |  9 +++++++++
 dialects/mysql.go   |  4 +++-
 schemas/column.go   |  1 +
 session_schema.go   |  1 +
 tags/tag.go         | 45 ++++++++++++++++++++++++++-------------------
 5 files changed, 40 insertions(+), 20 deletions(-)

diff --git a/dialects/dialect.go b/dialects/dialect.go
index dc96f73a..e57961b6 100644
--- a/dialects/dialect.go
+++ b/dialects/dialect.go
@@ -280,5 +280,14 @@ func ColumnString(dialect Dialect, col *schemas.Column, includePrimaryKey bool)
 		}
 	}
 
+	if col.IsOnUpdate {
+		if _, err := bd.WriteString("ON UPDATE CURRENT_TIMESTAMP"); err != nil {
+			return "", err
+		}
+		if err := bd.WriteByte(' '); err != nil {
+			return "", err
+		}
+	}
+
 	return bd.String(), nil
 }
diff --git a/dialects/mysql.go b/dialects/mysql.go
index 5f1d28e5..10332b26 100644
--- a/dialects/mysql.go
+++ b/dialects/mysql.go
@@ -414,7 +414,9 @@ func (db *mysql) GetColumns(queryer core.Queryer, ctx context.Context, tableName
 		if extra == "auto_increment" {
 			col.IsAutoIncrement = true
 		}
-
+		if strings.Contains(extra, "ON UPDATE CURRENT_TIMESTAMP") {
+			col.IsOnUpdate = true
+		}
 		if !col.DefaultIsEmpty {
 			if !alreadyQuoted && col.SQLType.IsText() {
 				col.Default = "'" + col.Default + "'"
diff --git a/schemas/column.go b/schemas/column.go
index db66a3a6..28592aa5 100644
--- a/schemas/column.go
+++ b/schemas/column.go
@@ -30,6 +30,7 @@ type Column struct {
 	Length2         int
 	Nullable        bool
 	Default         string
+	IsOnUpdate      bool
 	Indexes         map[string]int
 	IsPrimaryKey    bool
 	IsAutoIncrement bool
diff --git a/session_schema.go b/session_schema.go
index 9ccf8abe..b6afcba4 100644
--- a/session_schema.go
+++ b/session_schema.go
@@ -296,6 +296,7 @@ func (session *Session) Sync2(beans ...interface{}) error {
 			for _, col2 := range oriTable.Columns() {
 				if strings.EqualFold(col.Name, col2.Name) {
 					oriCol = col2
+					oriCol.IsOnUpdate = col.IsOnUpdate
 					break
 				}
 			}
diff --git a/tags/tag.go b/tags/tag.go
index ee3f1e82..b96e145b 100644
--- a/tags/tag.go
+++ b/tags/tag.go
@@ -57,25 +57,26 @@ type Handler func(ctx *Context) error
 var (
 	// defaultTagHandlers enumerates all the default tag handler
 	defaultTagHandlers = map[string]Handler{
-		"<-":       OnlyFromDBTagHandler,
-		"->":       OnlyToDBTagHandler,
-		"PK":       PKTagHandler,
-		"NULL":     NULLTagHandler,
-		"NOT":      IgnoreTagHandler,
-		"AUTOINCR": AutoIncrTagHandler,
-		"DEFAULT":  DefaultTagHandler,
-		"CREATED":  CreatedTagHandler,
-		"UPDATED":  UpdatedTagHandler,
-		"DELETED":  DeletedTagHandler,
-		"VERSION":  VersionTagHandler,
-		"UTC":      UTCTagHandler,
-		"LOCAL":    LocalTagHandler,
-		"NOTNULL":  NotNullTagHandler,
-		"INDEX":    IndexTagHandler,
-		"UNIQUE":   UniqueTagHandler,
-		"CACHE":    CacheTagHandler,
-		"NOCACHE":  NoCacheTagHandler,
-		"COMMENT":  CommentTagHandler,
+		"<-":        OnlyFromDBTagHandler,
+		"->":        OnlyToDBTagHandler,
+		"PK":        PKTagHandler,
+		"NULL":      NULLTagHandler,
+		"NOT":       IgnoreTagHandler,
+		"AUTOINCR":  AutoIncrTagHandler,
+		"DEFAULT":   DefaultTagHandler,
+		"CREATED":   CreatedTagHandler,
+		"UPDATED":   UpdatedTagHandler,
+		"DELETED":   DeletedTagHandler,
+		"VERSION":   VersionTagHandler,
+		"UTC":       UTCTagHandler,
+		"LOCAL":     LocalTagHandler,
+		"NOTNULL":   NotNullTagHandler,
+		"INDEX":     IndexTagHandler,
+		"UNIQUE":    UniqueTagHandler,
+		"CACHE":     CacheTagHandler,
+		"NOCACHE":   NoCacheTagHandler,
+		"COMMENT":   CommentTagHandler,
+		"ON_UPDATE": OnUpdateTagHandler,
 	}
 )
 
@@ -215,6 +216,12 @@ func UniqueTagHandler(ctx *Context) error {
 	return nil
 }
 
+// OnUpdateTagHandler
+func OnUpdateTagHandler(ctx *Context) error {
+	ctx.col.IsOnUpdate = true
+	return nil
+}
+
 // CommentTagHandler add comment to column
 func CommentTagHandler(ctx *Context) error {
 	if len(ctx.params) > 0 {