hql login

Transferred from: http://www.cnblogs.com/AnswerTheQuestion/p/6512701.htmlThis essay will document Hql's frequently used query statements to facilitate future viewing.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{ private int id; Private String name; Private String type; Priv

Let's summarize the common syntax of the HQL statement: FROM clause:; Select clause: Used to select objects and attributes; WHERE clause: The restriction condition used to express the query statement; Use an expression: generally used in the WHERE clause; ORDER BY clause: used for sorting; Here is a summary of the HQL query based on a table of one of my projects:

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

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

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

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

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{ private int id; private String name; Private String type; Private setClassroom class:public class classroom{ private int id; private String name; Private special special; Private setStudent class:public class student

Tags: blank LAN purpose based on add now programming language Hibernate modeSQL: Full-Name Structured Query Language (structured Query Language), a special purpose programming language, is a database query and programming language for accessing data and querying, updating and managing relational database systems , and is also the extension of the database script file.HQL: HQL (Hibernate query Language) queries provide richer and more flexible query ch

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

Hql: hibernate qusery language. If you are familiar with it, you will find that it is very similar to SQL. However, you should not be confused by the illusion that hql is object-oriented (OO, looking at every object with a life perspective, they are so vivid ). If you have some knowledge about Java and SQL statements, hql is easy for you. You can take full advant

?) **)String hql = "from user where username =?";list　　Focus : HQL uses entity query technology, such as the following example: String hql= "from user User"; List list=session. CreateQuery (HQL). List (); The result of the above code execution is to query out all the data corresponding to the user entity object , and e