Grails的SQL查询 [英] Grails sql queries

问题描述

假设我有这样的事情：

  def example = {
 def temp = ConferenceUser.findAllByUser（User .get（session.user））
 [temp：temp] 
} 
  

解释我的问题：
尽管动态查找器非常易于使用且学习速度快，但我必须替换我的网站的动态查找器以查找SQL查询，因为这是一项要求。因为我不太了解SQL，所以我的主要问题是：a）我使用SQLS数据库，驱动程序和数据源配置良好，我的网站工作正常就像现在这样。如果我想替换sql语句的findAllByUser，我应该这样做：

  def dataSource 
 ... 
 def db = new Sql（dataSource）
 def temp = db.rows（SELECT ...）
   
 
  b）那会起作用吗？我的意思是，如果我使用findAllByUser，临时对象将成为一个列表，并且是否需要打开一个到数据库的连接=？
    方案

是的，用grails你可以做简单的sql和hql查询。 HQL是'hibernate查询语言'，允许你编写类似sql的语句，但是使用你的域类和属性来代替表名和列名。要做一个hql查询，请执行以下操作：

  def UserList = ConferenceUser.executeQuery（'from ConferenceUser cu其中cu.user =？ '，[user]），
  

这里有一个参数化查询 - executeQuery看到？在hql字符串中，并将数组中的参数替换为方法的第二个参数（本例中为 [user] ）。

请参阅
http：/ /grails.org/doc/latest/ref/Domain%20Classes/executeQuery.html

你可以看到如何使用Grails进行sql查询

插入的sql查询grails

Imagine I have something like this:

def example = {
   def temp = ConferenceUser.findAllByUser(User.get(session.user))
   [temp: temp]
}

Explaining my problem: Although dynamic finders are very easy to use and fast to learn, I must replace dynamic finders of my website for sql queries because it is a requirement. As I don't understand SQL that much, my main questions are:

a) I am using an SQLS database, with the drivers and datasource good configured and my website works as it is right now. If I want to replace the "findAllByUser" for an sql statement, should i do something like this:

def dataSource
...
def db = new Sql(dataSource)
def temp = db.rows("SELECT ... ")

b) And that will work? I mean, the temp object will be a list as it is if I use "findAllByUser", and do I need to open a connection to the database =?

解决方案

yes, with grails you can do both plain sql and hql queries. HQL is 'hibernate query language' and allows you to write sql-like statements, but use your domain classes and properties instead of the table names and column names. To do an hql query, do something like

def UserList = ConferenceUser.executeQuery('from ConferenceUser cu where cu.user = ?', [user]),  

what you have here is a parameterized query -- executeQuery sees the ? in the hql string and substitutes the arguments in the array that is the second parameter to the method([user] in this case) for you.

See http://grails.org/doc/latest/ref/Domain%20Classes/executeQuery.html

and you can see this on how to do sql queries with Grails

Sql query for insert in grails

这篇关于Grails的SQL查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！