General operations collection for the "Hibernate" Data Session Object

Because Hibernate is ORM, programmers don't need to write SQL statements. All operations are done through the manipulation of the object.

1, native session transaction management

Transaction tx = Session.begintransaction (); // Open Transaction tx.commit (); // Commit a transaction

Querying data

Querying data with a primary key value of 1 in the user table

Object user = Session.get (user.  Class, 1);

Inserting data

Inserting a new piece of data into a data table

User user=new  User (); User.setid (4); User.setname ("Jordan"); User.setpassword (" abc123 "= Session.begintransaction (); // Open Transaction session.save (user); Tx.commit (); // Submit

Update all data

Assigns all fields with ID 4 in the data table,

If a field in the corresponding user table does not have a given value in the inserted object, it will be assigned a value of NULL

User user=new  User (); User.setid (4); User.setname ("James"=  Session.begintransaction (); session.update (user); // This will change the data with ID 4 to ' James ' and the password field value to null. Tx.commit ();

Updating part of the data

If you update only some of the fields in a row in the datasheet, you can follow the idea

Ideas:

Get all the data out first,

Then change the data that needs to be modified

Make all updates again.

This allows you to implement a partial update

User user = (user) session.get (user).  Class, 4); User.setpassword ("abcdef"= Session.begintransaction (); // Open Transaction session.update (user); Tx.commit (); // Commit a transaction

Delete data

Delete data with primary key 2

User user=new  User (); User.setid (2); // use primary key as deletion condition Transaction tx = session.begintransaction (); session.delete (user); Tx.commit ();

2,HQL Querying all data

SQL statement: SELECT * from user

HQL Operation:

String hql= "from User"== Query.list (); // Query all data  for (Object user:list) {    System.out.println (user);}

Finding data for a specified condition

SQL statement: SELECT * from user where uid=2;

HQL Operation:

String hql= "from User where id=?"  = session.createquery (HQL); Query.setinteger (0, 2); // Setting Parameters Object result = Query.uniqueresult (); // get the only results SYSTEM.OUT.PRINTLN (result);

Using pre-defined functions

SQL statement: SELECT COUNT (*) from user

HQL Operation:

String hql= "SELECT COUNT (*) from User"== Query.uniqueresult (); // The result must be plastic . SYSTEM.OUT.PRINTLN (result);

Page out

SQL statement: SELECT * from User limit

HQL Operation:

String hql= "from User"= session.createquery (HQL); Query.setfirstresult (1); // query Start position query.setmaxresults (2); // Specify the number of queries List List = query.list ();  for (Object user:list) {    System.out.println (user);}

Update

SQL statement: Update user set uname= ' Honny ' where uid=1

HQL Operation:

String hql= "Update User set name=?" where id=? "  = session.createquery (HQL); Query.setstring (0, "Honny"); Query.setinteger (1, 1= Session.begintransaction (); // Open Transaction int rows = query.executeupdate (); // number of rows that are affected tx.commit (); // Commit a transaction System.out.println ("Number of affected rows:" +rows);

General operations collection for the "Hibernate" Data Session Object