From fa86bebb4bcde9fb3fab9520453d9f25d741294d Mon Sep 17 00:00:00 2001 From: Lynnworld <lynnworld7@gmail.com> Date: Thu, 4 Dec 2014 18:08:52 +0800 Subject: [PATCH] Update db-dao.md --- docs/guide-zh-CN/db-dao.md | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/docs/guide-zh-CN/db-dao.md b/docs/guide-zh-CN/db-dao.md index 542e396..6c2df28 100644 --- a/docs/guide-zh-CN/db-dao.md +++ b/docs/guide-zh-CN/db-dao.md @@ -98,7 +98,7 @@ $connection = new \yii\db\Connection([ $connection->open(); ``` -小提示:如果在创建了连接后需要执行额外的 SQL 查询,可以添加以下代码到应用配置文件: +>小提示:如果在创建了连接后需要执行额外的 SQL 查询,可以添加以下代码到应用配置文件: ``` return [ @@ -117,34 +117,44 @@ return [ ]; ``` -SQL 基础查询 +##SQL 基础查询 一旦有了连接实例就可以通过[[yii\db\Command]]执行 SQL 查询。 -SELECT 查询 - +###SELECT 查询 查询返回多行: +``` $command = $connection->createCommand('SELECT * FROM post'); $posts = $command->queryAll(); +``` 返回单行: - +``` $command = $connection->createCommand('SELECT * FROM post WHERE id=1'); $post = $command->queryOne(); -查询多列值: +``` +查询多行单值: +``` $command = $connection->createCommand('SELECT title FROM post'); $titles = $command->queryColumn(); +``` 查询标量值/计算值: +``` $command = $connection->createCommand('SELECT COUNT(*) FROM post'); $postCount = $command->queryScalar(); -UPDATE, INSERT, DELETE 更新、插入和删除等 +``` + +###UPDATE, INSERT, DELETE 更新、插入和删除等 如果执行 SQL 不返回任何数据可使用命令中的 execute 方法: +``` $command = $connection->createCommand('UPDATE post SET status=1 WHERE id=1'); $command->execute(); +``` + 选择以下考虑到引用了恰当表名和列名的语法是可能的: // INSERT -- libgit2 0.27.1