add table & column comment for postgres（add table comment for mysql） #2067

让 postgres 支持字段注释，只在 v1.2.5 上测试过（不知道怎么 import master）

发现 master 分支好像大改了？模式表名带 schema 了

使用方式和 mysql 相同

	type User struct {
		Id int64	`xorm:"pk autoincr"`
		Name string `json:"name" xorm:"not null default '' varchar(50) index(name_age) comment('用户 (it''s) 1; 名')"`
		Salt string
		Age int		`json:"age" xorm:"not null default 0 int(10) index(name_age) comment('年龄')"`
		Passwd string `xorm:"varchar(200)"`
		CreatedAt time.Time `xorm:"created"`
		UpdatedAt time.Time `xorm:"updated"`
	}

	_ = engine.Sync(new(User))
    
    
    func (model User) TableComment() string {
    	return "表注释"
    }

You should change dialects/postgres.go but not there.

per my comment above.

@lunny 已经移到 dialects 了，感觉 master 代码和 v1.2.5 相差很多，接口都变了

现在支持了字段注释和表注释

我发现 dialects/mysql.go 貌似没有用到 schema？mysql 里的库也相当于 pgsql 里的 schema

Thank you very much! Could you add some tests here? I think we have some with comment for MySQL.

How about also add simliar test cases for postgres?

How about also add simliar test cases for postgres?

parser.Parse only set table.Commet, it will be used in dialects

i don't know how to import master branch in my project

@lunny 看一下，能合并了么

@lunny has space and semicolon

commentSQL := "; "
commentSQL += "xxxx"

@lunny has space and semicolon
commentSQL := "; "
commentSQL += "xxxx"

I mean in function ModifyColumnSQL

@lunny has space and semicolon
commentSQL := "; "
commentSQL += "xxxx"
I mean in function ModifyColumnSQL

@lunny 我不太明白，应该在哪加空格，请指点一下

func (db *postgres) ModifyColumnSQL(tableName string, col *schemas.Column) string {
	quoter := db.dialect.Quoter()
	modifyColumnSQL := ""
	commentSQL := "; "

	if len(db.getSchema()) == 0 || strings.Contains(tableName, ".") {
		modifyColumnSQL = fmt.Sprintf("ALTER TABLE %s ALTER COLUMN %s TYPE %s", quoter.Quote(tableName), quoter.Quote(col.Name), db.SQLType(col))
		commentSQL += fmt.Sprintf("COMMENT ON COLUMN %s.%s IS '%s'", quoter.Quote(tableName), quoter.Quote(col.Name), col.Comment)
		return modifyColumnSQL + commentSQL
	}

	modifyColumnSQL = fmt.Sprintf("ALTER TABLE %s.%s ALTER COLUMN %s TYPE %s", quoter.Quote(db.getSchema()), quoter.Quote(tableName), quoter.Quote(col.Name), db.SQLType(col))
	commentSQL += fmt.Sprintf("COMMENT ON COLUMN %s.%s.%s IS '%s'", quoter.Quote(db.getSchema()), quoter.Quote(tableName), quoter.Quote(col.Name), col.Comment)
	return modifyColumnSQL + commentSQL
}

@lunny 受累看一下能合并了么，之前您说在 ModifyColumnSQL 里，两段 sql 之前应该有一个空格

但是在 commentSQL 初始化的时候，这个空格就已经有了，还有一个分号

like this

commentSQL := "; "
commentSQL += "xxxx"

return modifyColumnSQL + commentSQL

 		return nil, err
 	}
 	// if bean has Comment Method, then set table.Comment

 		return v.Interface().(TableComment).TableComment()
 	}
 	return ""

 				if err = session.addColumn(col.Name); err != nil {
 					return err
 				}

 	return "p_parseTableName"
 }
 func (p ParseTableName2) TableComment() string {

add table & column comment for postgres（add table comment for mysql） #2067

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