Sequelize-nodejs-11-Raw queries
Raw queries原始查询
就是使用了原始的查询语句,如UPDATE users SET y = 42 WHERE x = 12
As there are often use cases in which it is just easier to execute raw / already prepared SQL queries, you can utilize the function sequelize.query
.
当经常有使用更简单的执行原始/已经准备好的SQL查询的情况出现时,你可以使用函数sequelize.query
。
By default the function will return two arguments - a results array, and an object containing metadata (affected rows etc.). Note that since this is a raw query, the metadata (property names etc.) is dialect specific. Some dialects return the metadata "within" the results object (as properties on an array). However, two arguments will always be returned, but for MSSQL and MySQL it will be two references to the same object.
默认函数将返回两个参数-一个结果数组和一个包含元数据(被影响的行等数据)的对象。记住因为这是一个原始查询,元数据(属性名等)使用的语言是指定的。一些语言返回的元数据带有结果对象(像数组中的属性)。可是两个参数总是被返回的,但是对于MSSQL and MySQL来说这两个参数将是同个对象的两个引用
sequelize.query("UPDATE users SET y = 42 WHERE x = 12").spread((results, metadata) => {
// Results will be an empty array and metadata will contain the number of affected rows.
})
In cases where you don't need to access the metadata you can pass in a query type to tell sequelize how to format the results. For example, for a simple select query you could do:
在这个例子中,你不需要访问元数据,你可以传递一个查询类型去告诉sequelize怎样格式化结果。比如下面的简单select查询:
sequelize.query("SELECT * FROM `users`", { type: sequelize.QueryTypes.SELECT})
.then(users => {
// We don't need spread here, since only the results will be returned for select queries
})
Several other query types are available. Peek into the source for details
其他的查询类型也是可用的
A second option is the model. If you pass a model the returned data will be instances of that model.
模型的第二个选项。如果你在第二个选项中传递的是模型,那么返回数据将是模型的实例
// Callee is the model definition. This allows you to easily map a query to a predefined model
sequelize.query('SELECT * FROM projects', { model: Projects }).then(projects => {
// Each record will now be a instance of Project
})
Replacements
Replacements in a query can be done in two different ways, either using named parameters (starting with :
), or unnamed, represented by a ?
. Replacements are passed in the options object.
在查询中替代能够以两种不同方式实现,要么使用命名变量(以:开始),要么不命名,以?来替代。替代将在options对象中被传递
- If an array is passed,
?
will be replaced in the order that they appear in the array如果传递的是数组,?将会以其出现在数组中的顺序被替代 - If an object is passed,
:key
will be replaced with the keys from that object. If the object contains keys not found in the query or vice versa, an exception will be thrown.如果传递的是对象,:键将被来自对象的键值所替代。如果对象包含的键在查询中没有找到,将抛出一个异常,反之亦然
sequelize.query('SELECT * FROM projects WHERE status = ?',
{ replacements: ['active'], type: sequelize.QueryTypes.SELECT }
).then(projects => {
console.log(projects)
}) sequelize.query('SELECT * FROM projects WHERE status = :status ',
{ replacements: { status: 'active' }, type: sequelize.QueryTypes.SELECT }
).then(projects => {
console.log(projects)
})
Array replacements will automatically be handled, the following query searches for projects where the status matches an array of values.
数组替代将会自动处理,即下面对对象中status满足数组值的查询搜索
sequelize.query('SELECT * FROM projects WHERE status IN(:status) ',
{ replacements: { status: ['active', 'inactive'] }, type: sequelize.QueryTypes.SELECT }
).then(projects => {
console.log(projects)
})
To use the wildcard operator %, append it to your replacement. The following query matches users with names that start with 'ben'.
为了使用通配符%并添加其道替代中。以下的查询匹配名字是以'ben'开始的用户
sequelize.query('SELECT * FROM users WHERE name LIKE :search_name ',
{ replacements: { search_name: 'ben%' }, type: sequelize.QueryTypes.SELECT }
).then(projects => {
console.log(projects)
})
Bind Parameter绑定变量
Bind parameters are like replacements. Except replacements are escaped and inserted into the query by sequelize before the query is sent to the database, while bind parameters are sent to the database outside the SQL query text. A query can have either bind parameters or replacements. Bind parameters are referred to by either $1, $2, ... (numeric) or $key (alpha-numeric). This is independent of the dialect.
绑定变量与替换相似。除了替换是在查询传送给数据库之前通过sequelize进行除去和插入查询的,而绑定变量是在SQL查询文本外传递给数据库的。查询能够有绑定变量或有替换。绑定变量将通过$1, $2, ... (numeric) 或$key (alpha-numeric)提及。与使用的语言不相关
- If an array is passed,
$1
is bound to the 1st element in the array (bind[0]
)如果传递的是数组,$1
将会于数组中的第一个元素(bind[0]
)绑定 - If an object is passed,
$key
is bound toobject['key']
. Each key must begin with a non-numeric char.$1
is not a valid key, even ifobject['1']
exists.如果传递的是对象,$key
与object['key']
绑定。每个键一定是以非数字字符开始的。$1
不是一个有效键,即使object['1']
存在 - In either case
$$
can be used to escape a literal$
sign.在上面两种情况下,$$
都可以用来转义字符$
The array or object must contain all bound values or Sequelize will throw an exception. This applies even to cases in which the database may ignore the bound parameter.
数组或对象必须包含所有边界值,否则Sequelize将抛出异常。这将应用于数据库可能忽略边界变量的情况
The database may add further restrictions to this. Bind parameters cannot be SQL keywords, nor table or column names. They are also ignored in quoted text or data. In PostgreSQL it may also be needed to typecast them, if the type cannot be inferred from the context $1::varchar
.
数据库可能添加更多的限制。绑定变量不能作为SQL的关键字,也不能作为表或列名。他们将会在引用文本或数据中被忽略。在PostgreSQL中,如果类型不能从上下文 $1::varchar
中被推导出的话,它可能也需要将他们定型。
sequelize.query('SELECT *, "text with literal $$1 and literal $$status" as t FROM projects WHERE status = $1',
{ bind: ['active'], type: sequelize.QueryTypes.SELECT }
).then(projects => {
console.log(projects)
}) sequelize.query('SELECT *, "text with literal $$1 and literal $$status" as t FROM projects WHERE status = $status',
{ bind: { status: 'active' }, type: sequelize.QueryTypes.SELECT }
).then(projects => {
console.log(projects)
})
Sequelize-nodejs-11-Raw queries的更多相关文章
- [转]Raw Queries in Laravel
本文转自:https://fideloper.com/laravel-raw-queries Business logic is often complicated. Because of this, ...
- 基于Nodejs的sequelize操纵数据库
## 使用基于ORM架构的sequelize操纵数据库 ### 1.技术背景 ```Sequelize是一个基于promise的关系型数据库ORM框架,*********************技术文 ...
- 【前端】nodejs的ORM框架sequelize的工厂化
转载请注明出处:http://www.cnblogs.com/shamoyuu/p/sequelize_factory.html 一.什么是sequelize nodejs的后台在操作数据库的时候,需 ...
- Executing Raw SQL Queries using Entity Framework
原文 Executing Raw SQL Queries using Entity Framework While working with Entity Framework developers m ...
- C++11中的raw string literals
作为一名C++书看得少得可怜的新手,我一直没有勇气去系统地学习一下C++ 11添加的新特性.不过,平日里逛论坛,阅读大犇们的博客,倒是了解了一些.比如,这个帖子: 如何绕过g++ 4.8.1那个不能在 ...
- Sequelize Docs 中文文档 v4
Sequelize Docs 中文文档 v4 写在前面 Sequelize 是一个基于 promise 的 Node.js ORM, 目前支持 Postgres, MySQL, SQLite 和 Mi ...
- Django-官网查询部分翻译(1.11版本文档)-QuerySet-字段查找-06
目录 Making queries 进行查询 创建一个对象(一条数据记录) 保存修改的表对象 保存外键字段或多对多字段(ForeignKey or ManyToManyField fields) Re ...
- Sequelize 类 建立数据库连接 模型定义
1:Sequelize 类 Sequelize是引用Sequelize模块获取的一个顶级对象,通过这个类可以获取模块内对其他对象的引用.比如utils.Transaction事务类.通过这个顶级对象创 ...
- Sequelize 基本操作
Sequelize 是 Node 的一个 ORM(Object-Relational Mapping) 框架,用来方便数据库操作. 配置 sequelize 以 mysql 为例 首先我们要引入npm ...
随机推荐
- php判断是否isPhone、is_weixin
protected function isPhone(){ $agent = strtolower($_SERVER['HTTP_USER_AGENT']); //pc请求头信息数组 $pc_arr= ...
- tr,td高度不生效
功能:表格内容较长,但是页面高度有限,超出显示滚动条 阻碍:给tr或者td加高度都不生效,不显示滚动条 解决方案:td中加div,设置高度和内容溢出时的样式 <table border='1' ...
- curl 封装类
<?php /** * author: zbseoag * QQ: 617937424 用法: $content = Curl::instance()->url($url)->get ...
- 【c++错误】类的语法错误 error c2533:constructors not allowed a return type(构造函数不允许返回一个类型)
今天编写类的程序的时候不小心把类后的分号忘写了,就出现上面的错误提示. 顺便复习下类的正确格式: class 类名 { public: //习惯上将公有类型放在前面,便于阅读 ……(外部接口) pro ...
- Kubernetes核心概念简介
本文将会简单介绍Kubernetes的核心概念.因为这些定义可以在Kubernetes的文档中找到,所以文章也会避免用大段的枯燥的文字介绍.相反,我们会使用一些图表(其中一些是动画)和示例来解释这些概 ...
- Tomcat、Apache、IIS这三种Web服务器来讲述3种搭建JSP运行环境的方法
一.相关软件介绍 1. J2SDK:Java2的软件开发工具,是Java应用程序的基础.JSP是基于Java技术的,所以配置JSP环境之前必须要安装J2SDK. 2. Apache服务器:Apache ...
- Flex Box 简单弹性布局
弹性盒子模型有两种规范:早起的display:box 和后期的display:flex.它可以轻易的实现均分.浮动.居中等灵活布局,在移动端只考虑webkit内核时很实用. 一.display:box ...
- Qt——元对象和属性机制
http://www.cnblogs.com/hellovenus/p/5582521.html 一.元对象 元对象(meta object)意思是描述另一个对象结构的对象,比如获得一个对象有多少成员 ...
- 团队开发心得(May)
经过之前一个多月的准备工作(包括去求调研.技术选型.知识储备等等),这个月开发工作终于步入正轨,下面谈谈我的心得体会. 个人收获方面,我选择了加入数据库小组,进行数据库方面的开发.刚开始的时候我是个小 ...
- .NET 2.0 参考源码索引
http://www.projky.com/dotnet/2.0/Microsoft/CSharp/csharpcodeprovider.cs.htmlhttp://www.projky.com/do ...