hql requirements

Basic usage of hql 1. Object QueryString hql = "from Tuser "; Executing this statement will return records of Tuser and Tuser sub-classes. Hql = "from Java. Lang. Object"Records of all database tables in the database are returned. Where statementHql = "from Tuser as user where user. Name = 'yyy '"; The same can be omitted for.Hql = "from Tuser user where user. Na

Operators yesterday to ask a question, the table's fuzzy query only support the current page, the query needs a page page of the turn, the user experience needs to be improved. The technical level is because the query invokes the public pagination Pagequery (final criterion[] criterions, final integer startLine, final integer PageS ize, Final String by, final Boolean Isasc) {} method, which is good for single table query support, adding query conditions to criterion array, executing pagequery c

1. Find (String hql); General QueryExample: This.gethibernatetemplate (). Find ("from User");2. Find (String hql,object value);//A query conditionExample: This.gethibernatetemplate (). Find ("from User u where u.name=?", "Test");3. Find (String hql,object[] values);//Multiple query conditionsExample: This.gethibernatetemplate (). Find ("from User u where u.name=?

The content of this section Query methods in the NHibernate NHibernate Query Language (HQL) 1.from clause 2.select clause 3.where clause 4.order BY clause 5.group BY clause Example analysis Conclusion In the previous section, we initially set up a nhibernate program, completed mapping the Customer table and read the data function, this section and the next section we discuss the query method in the N

Hibernate-based Hibernate query language (hql) HqlKeywords in hql are case-insensitive, but attributes and class names are case-sensitive.1. Simple attribute Query [important]* For a single attribute query, a list of returned result set attributes is returned. The element type is consistent with the corresponding attribute type in the object class.* When querying multiple attributes, the returned collectio

In the integration process of SSH framework, novice will often encounter this problem. When we use the HQL statement query, the console error: XXX is not mapped. And at this time, many feel good English students will be dizzy. It then starts by checking that the mapping file for the entity class is *.hbm.xml correct, adding the mapping file to the spring configuration file, and so on. Then highlight a pass, still not effective.Let's get down to the ch

1. Unable to locate appropriate constructor on class .... Similar to "select new uservo (U. ID, U. Name) from user u where u. ID> 100" In this case, uservo must have a constructor that matches the (ID, name) type. 2. Like Fuzzy match: View plaincopy to clipboardprint? Public list String hql = "select * from user u where u. name like? " List Return result; } Public list Note that "%" is passed in as a parameter rather than directly spelled i

) {Session=sf.opensession (); Threadlocal.set (session); } returnsession; } Public Static voidSave (Object obj) {Session session=opensession (); Transaction TX=NULL; Try{TX=session.begintransaction (); Session.save (obj); Tx.commit (); } Catch(Exception e) {if(tx! =NULL) {tx.rollback (); } Throw Newruntimeexception (E.getmessage ()); } finally { if(Session! =NULLSession.isopen ()) {Session.close (); }}} @SuppressWarnings ("Unch

Use the Hibernate framework to generate executable SQL statements for hql-Oracle DialectIntroduction: Why is this requirement derived from the company's project requirements? The company's project uses java's struts2 + spring2.5 + oracle middleware tuxedo. The database uses Oracle, but because it does not directly connect to the database, the middleware processing method does not require too many services,

Having read the second part of the book today, I feel that there are a lot of things worth studying.First, the requirements model provides guidance that is often more thorough than just "for example". It gives insight into what's going on. It can help raise questions. In some cases, it can lead to writing one (or more) requirements that are very different from first impressions. Answering a big question oft

First, batch processing operationsBulk processing of data is the processing of large amounts of data in a transactional scenario. In applications where bulk operations are difficult to avoid,Hibernate provides the following ways to process data in batches:(1) Use HQL The database level for bulk operations(2) Use JDBC API for bulk operations database level(3) Use Session for batch operations will go into cache1. using

The previous article briefly introduced HQL it as Hibernate query language, encapsulated the basic SQL of all query operations, HQL can implement the database file additions and deletions, this article focuses on HQL entity object Query method.first, the Entity object queryEntity object queries are the basis of HQL que

One, Entity object query Entity object queries are the basis of HQL queries, and as an object query language, the contents of the query string are replaced with the class name and the property name of the class, unlike SQL in query operations. This kind of query method is relatively simple, as long as has the SQL Foundation, uses the HQL is very simple, but some questions need to notice, is the query obtai

Almost all software project products are the information set exported from the demand, and the demand has become the entrance for software R D. People familiar with the IT industry have no objection to this kind of cognition. Project requirements, as the name implies, meet the project needs and the goals and requirements of the project attached to the development of enterprise/organization management. The

For example, for the Tuser class 1. Object Query String hql = "from Tuser "; Executing this statement will return records of Tuser and Tuser sub-classes. Note: If the Tuser class has a foreign key, an error is returned during the query! Solution: Select alias. Attribute from class as alias. No alias. Attribute still reports error! Hql = "from Java. Lang. Object" Records of all database tables in the databas

Here by defining three classes, special, classroom, student to do the test, special and classroom is a one-to-many, classroom and student is a one-to-many relationship, here just paste the property code of these three beans:Special class: Public class special{ privateint ID; Private String name; Private String type; Private Set Rooms; ..........}Classroom class: Public class classroom{ privateint ID; Private String name; Private special special; Private set stu

Native SQL query: @Testpublic void Querysqltest () {Session session=null;try{session=hibernateutil.opensession (); String sql= "SELECT * from T_student where student_name like?"; SQLQuery query=session.createsqlquery (SQL); query.addentity (student.class);//starting from the first few records Query.setfirstresult (0);// Query.setmaxresults per page size: query.setstring (0, "% wang"); List Object navigation Query (inner JOIN): @Testpublic void Qu

HQL Sentence Learning:(1) Preliminary understanding of HQL① HQL is the object-oriented query language, which uses the class name and the property name when querying,and theSql query uses the table name and the field name .② Case Sensitive③ Package Name: If the class name is not duplicated, do not write the package name, if the different packages have the same cla

Recently has been using SPRING-DATA-JPA this thing, feel the method of annotation HQL statement is a very common method,There are some experiences on HQL to share:I. Join of the HQLThe advantage of HQL is the direct correlation, but there are some places to be aware of when a join query is made through HQL statements:H

Hql instance: 1.Query all records in the Table: from category 2.Conditional query with WHERE clause: from Category C where c. Name> 'c5' 3.The result is sorted by a certain field: from Category C order by C. Name DESC (DESC indicates descending order, ASC indicates Ascending Order) 4.Remove duplicate records to obtain a single record: Select distinct C from Category C order by C. Name DESC 5.Query with parameters: from Category C where c. ID