hql requirements

Hibernate is equipped with a very powerful query language, that is, HQL (Hibernate query Language), hql look like SQL, but just similar to the syntax structure, HQL is an object-oriented query, he can understand the concepts of inheritance, polymorphism.HQL are case-sensitive, and SQL statement keywords (such as SELECT, From,where, and so on) are case insensitive

Hibernate Query Language abbreviated to HQL, is the longest in the real development of hibernate package mode.HQL provides a query method that is closer to the traditional SQL statement:Entity query:where select * from TUser in the "from TUser" ==sql. is to poll all entities, and if Tuser has a sub-class table below it, all the data for the subclass table will be found.How to query a specified entity:Property query:Query the Name property collection f

With HQL: More search Help Use list as a condition result List lst.add(14); lst.add(15); lst.add(17); String hql = "from Students s where s.SId in (:lst)"; Query q = session.createQuery(hql); q.setParameterList("lst",lst); // 以一个实类作为参数条件 hql = "from Students s where s.class=:class"; q.setEntity("class",session.get(Cl

For example, for the Tuser class 1. Entity Query String hql = " from TUser"; Executing this statement returns the records of the Tuser and the Tuser subclass. Note: If the TUser class has a foreign key, the query will complain! Workaround: Select Alias. property from class as Alias. No aliases. Property still complains! hql = "from java.lang.Object" Returns a record of all the library tables in the d

Hql:hibernate Query Language. Features://>> 1, similar to SQL, the syntax in SQL is basically straightforward to use. >> 2,sql queries are columns in tables and tables; HQL queries are properties in objects and objects. >> 3,hql keywords are case-insensitive, and class names and property names are case-sensitive. >> 4,select can be omitted. 1, simple query, Employee is the entity name rather than the t

The problem caused by domain conventions is that password settings do not comply with the rules of the Policy Group. In this case, you need to set the response option in the domain policy to reduce the complexity of the password. (By default, the complexity must be at least 7 characters long and contain multiple letters and numbers) Windows Server 2003 solutionYes: Choose Start> program> Administrative Tools> Domain Security Policy> Account Policy> Password Policy The password must meet the comp

A short article prepared by my colleagues. I am lazy and paste it directly. 1.Define test Scope(Scope)(Scope refers to the purpose, purpose, and strategy of the test) The following issues should be considered during definition: A.What is the main purpose and guidance of application software? B.What are the main characteristics of application software? C.Which of the following components of the application software are relatively important? D.What are the most likely p

Some relevant suggestions on the requirements review 1, it is more important to discuss the products with the background. Can be as our group discusses the status quo and the specific causes of the situation to the solution, to the customer in today's business functions of some pain points and hate points, and then explain how our products are to solve the problem. 2, combined with the current hot issues for analysis. As we want to do the system is a

String hql= "Select C from Col C, userrole role where C.id=role.columnid and c.id=? and role.userid=?" this . Gethibernatetemplate (). Find (Hql,new Object[]{colid,userid}). Get (0); The Above returns an object entity that is of type Col String hql= "from Col C, userrole role where C.id=role.columnid and c.id=? and role.userid=?" this . Gethibernatetemp

1.HQL differs from Sql,from must be the name of the class that corresponds to the table reversal in the project.2. How to generate HQL statements using parameters:"= session.createquery (HQL); Query.setparameter (0, userId); // instead of the No. 0 question mark3.HQL can not write limit, but he has the method can be s

HQL:public boolean docreate (Dept vo) throws Exception {return this.sessionFactory.getCurrentSession (). Save (VO)! = null;} @Overridepublic boolean doupdate (Dept vo) throws Exception {String hql = "UPDATE Dept as D SET d.title=?" WHERE d.deptid=? "; Query query = this.sessionFactory.getCurrentSession (). CreateQuery (HQL); query.setstring (0, Vo.gettitle ()); Query.setinteger (1, Vo.getdeptid ()); return

HQL basic Query simple Query result for output and Iterator output, hqliterator The first HQL course: Hibernate Query Language: hibernate Query Language 　　 Syntax: Query: String hql = "from dept "; Query query = session. createQuery (hql); // returns the list set. Query is an object with many methods. The. list () meth

SQL ( Structured Query Language ) is the relational database query language. the from is followed by the "table name", where the condition is followed by "field in table"HQL ( Hibernate Query Language ) is an object-oriented query , The from is followed by the table name, where the condition is followed by the field in the table. When you use queries in Hibernate,Generally use HQL query statements. Becau

At the beginning, the HQL statement in the project was relatively casual, and later I checked the Query and Use the name parameter; colon + field name (or alias); equals to the original "? "Name;String hql = "from User as user where user. name =: name ";//....Query. setString ("name", name); // The first parameter must be named the same as that in hql; = "u

of the query parameter changes, the name of the state parameter is not necessary to adjust the program code. C, setparameter () method: 　　InHibernateof theHQLthe query can beSetparameter ()method states any type of parameter, as follows: 　　 String hql="From user user where user. name=:customername "; 　　Query query=session.createquery (HQL); 　　 query.setparameter ("customername", name,hibernate.string);

inner join（内连接） left outer join（左外连接）right outer join（右外连接）full join(全连接，并不常用)SQL中的条件用on即：left join... on...HQL中的条件用with即：left join... with... 语句inner join, left outer join以及 right outer join可以简写。 fromCat as cat joincat.mate asmate left joincat.kittens askitten 通过HQL的with关键字，你可以提供额外的join条件。 fromCat as cat left joincat.kittens askitten with kitten.bodyWeight > 10.0还有，一个"fetch"连接允许仅仅使用一个选择语句就将相关联

1.java.sql.date and Java.util.DateJava.sql.Date is inherited from Java.util.Date and assumes that dates1 (java.sql.Date) is assigned to Dates2 (java.util.Date)Dates2=new java.sql.Date (Dates1.gettime ()) can be performed by the following conversions;2. The difference between the methods in Preparestament Settimestamp () and setdate () and getdate (), Gettimestamp () in resultset:Gettimestamp (), Settimestamp () will get/set "date + Time" in the database, or it can be said to be a timestampGetDat

HQL DML mainly involves data manipulation in the Hive table, including: Load, INSERT, DELETE, EXPORT and IMPORT, detailed information see:https://cwiki.apache.org/ Confluence/display/hive/languagemanual+dmlDirectory: Loading files into tables Inserting data into Hive Tables from queries Writing data into the filesystem from queries Inserting values into tables from SQL Delete Application Demo Loading files into tables

,: start_date,: x1 SQL direct constant 'foo', 69, '2017-01-01 10:00:01. 0' Java public static final type constant eg. color. Tabby You can use the keyword in and between as follows: Code contentFrom domesticcat cat where Cat. Name between 'a 'and' B'From domesticcat cat where Cat. Name in ('foo', 'bar', 'baz ') The negative format can also be written as follows: Code contentFrom domesticcat cat where Cat. Name Not between 'a 'and' B'From domesticcat cat where Cat. Name not

Powerful ORM tool: nhibloud (iii) Five cores + simple object CRUD + HQL, ormcrud In the previous two articles, we have a rough understanding of nhib.pdf. Introduction to ORM: nhib.pdf (1) the role of nhib.pdf solves the conversion problem between objects and databases. ORM tool: nhib.pdf (2) use CodeSmith to quickly generate ing files and ing classes. Use CodeSmith to export ing classes from tables (usually called Entity) and ing files (tell you how