Hibernate saveHibernate offers too many ways to save objects, and there are a lot of differences between them, and here's a little bit of a different way:First, the preparation of knowledge:Before all, for Hibernate, it has three states of objects, transient, persistent, detachedBelow is a common translation approach:Transient: transient or free-formPersistent: Persistent stateDetached: off-tube or Free StateInstances of the Free State can be persisted by invoking the Save (), persist (), or Sav
J set Payroll to 999context. Users.update (U= U.name.contans ("J"), U2=NewUser {Salary =999}); //The first parameter can also pass in an existing iquaryable parameter as followsvarUsers = context. Users.where (U = u.firstname = ="FirstName"); context. Users.update (Users, U=NewUser {FirstName ="Newfirstname"});//Of course, my favorite is still this way of writing Bulk QueryIn fact, now the query is very good, the default delay query can meet the basic needs, but sometimes always want to be more
Background:Account and Group two objects, set up a two-way many-to-many relationship, Lazy=trueDo not use open session in view modeDo not use Hibernate level two cache
Test logic:Get a account object from the database (two group:1.administrators, 2.engineers)Modify this object's group information to: 1.invalid, 2.any oneThen call the DAO's Update method (this part of the code looks like this)
Code v1 only use merg
/*merge into detailed introductionThe merge statement is a new syntax for merging the UPDATE and INSERT statements oracle9i.With the merge statement, another table is queried based on the join criteria of one table or subquery,The connection condition matches the execution insert on the
DEFINETABLE: SCORE: Keys: thebaseinformationofstudentsDEFINECOLUMNS: STUNO: thestudentsIDintheUniversitySTUNAME: studentsnameCOURSENAME: coursenameCOURSESCORE: t
Define table: SCORE: using for save the students score informations STUDENTS: the base information of students define columns: STUNO: the students 'Id in theUniversity STUNAME: students 'name COURSENAME: course name COURSESCORE: t
Define table:
SCORE: using for save the students 'score informations
STUDENTS: the base information
Poj 2892 --- Tunnel Warfare (Single Point update and interval merge of line tree), poj2892 --- tunnel
Question Link
Description
During the War of Resistance Against Japan, tunnel warfare was carried out extensively in the vast areas of north China Plain. generally speaking, ages connected by tunnels lay in a line. cannot the two at the ends, every village was directly connected with two neighboring ones.
F
Problem descriptionduring the War of Resistance against Japan, tunnel warfare was carried off extensively in the vast area S of North China Plain. Generally speaking, villages connected by tunnels lay in a line. Except the ends, every village was directly connected with the neighboring ones.Frequently the invaders launched attack on some of the villages and destroyed the parts of tunnels in them. The eighth Route Army commanders requested the latest connection state of the tunnels and villages.
of the current range, and the right endpoint of the Left son is smaller than the left endpoint of the right son, therefore, you cannot directly add the left son's RMX and the right son's lmx, because the length of the query range may be smaller than the left son's RMX and the right son's lmx, therefore, a judgment should be added.
(Before the Code style is updated, the endpoint value is not saved in the online segment Tree node.) It is complicated before, and the endpoint value of this interval
HDU 1540 Tunnel Warfare (line segment Tree single point update + interval merge), hduwarfareProblem DescriptionDuring the War of Resistance Against Japan, tunnel warfare was carried out extensively in the vast areas of north China Plain. generally speaking, ages connected by tunnels lay in a line. cannot the two at the ends, every village was directly connected with two neighboring ones.Frequently the invad
The decision whether to update or insert into the target table is based on the condition in the ON clause. It allows you to avoid multiple insert and update DML statements.
The syntax is:
MERGE into table
USING Data_source
On (condition)
When matched THEN Update_clause
When not matched THEN insert_clause;
Case:
For example, now there are a, B two tables
SQL Server 2008 provides an enhanced SQL command merge for use in the msdn:http://msdn.microsoft.com/zh-cn/library/bb510625.aspx
Function: Inserts, updates, or deletes on the target table based on the results of joining with the source table. For example, you can synchronize two tables by inserting, updating, or deleting rows in a table based on differences found in another table.
Let's take a look at an example, if, there is a overall product list,
The following example uses MERGE to update or insert rows to modify the SalesReason table. When the NewName value in the source table matches the value in the Name column of the target table (SalesReason), The ReasonType column in the target table is updated. When the value of NewName does not match, the source row is inserted into the target table. This source table is a school
The following example uses
conflicting file, select "Mark as merge" Tap incoming mode-right item--Update (other conflict-free code on update line) Click Submit with outgoing mode-right item. Enter a comment to determine the submission. Experience: It's a good idea to double-click on the audit side of the list (all the modified) files in the view before committing, making sure there are
The idea of MyBatis hibernate was abandoned.Anyway, the stickers are first. Hibernate three status bits and switching between the use of functions;Summarize the functions of saveorupdate (), Save (), update (), merge ().Save (), update (): It's all very well understood.Save () generates a record in the database and, if there is one in the database, an error messa
MERGE is a composite statement used to implement INSERT, UPDATE, and DELETE operations at a time. Syntax: merge into table/view using (TABLE/VIEW/SUBQUERY) ON (condition) [when metched then update set column = expr/DEFAULT [WHERE condition] www.2cto.com [delete where condition] [when not matched then insert [(column,..
information Insert Values(U.shareduserid,u.platformid,u.creatdate,u.channelid,u.sharedmanagerid,0, U.qty,0,0,0,0,0,GETDATE()); ----------------------------------------is expected to be a gold------------------------------------------------------------------------- --------------------------------------------------------Merge intoDbo. Datasummary asDS using (SelectShareduserid,platformid,CONVERT(varchar( -), Createtime,111) asCreatdate,
1. Temporary State (Transient): the object created with new is not Persistent, not in Session, and the object in this state is called a temporary object; 2. Persistence (Persistent ): it has been persisted and added to the Session cache. For example, the object saved through the hibernate statement. Objects in this state are called persistent objects; 3. Detached: objects in the Session state are separated from persistent objects. For example, the Session cache is cleared. Persistent, but not in
Insert or update in MySQL (similar to Oracle's merge statement), oraclemerge
If the record does not exist in MySQL, insert the statement. If the record does not exist, update the statement. You can use the following statement:
Update a field:
Insert into tbl (columnA, columnB, columnC) VALUES (, 3) on duplicate key
entboost IM pc-side release v1.15 version, major version update content:
Added Chat window merging function;
Unify and perfect the user Electronic Business card, optimize the interface display and experience;
To increase peer-point video chat, save network bandwidth resources;
Add some rest API interface, and print trace log function to facilitate enterprise two development and application integration;
Solve known bugs and imp
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