cascade dk

Inverse and Cascade are the two most difficult properties to master in hibernate mapping. Both play a role in the object's associated operations. 1. Clarify the role of inverse and Cascadeinverse determines whether changes to the collection in the object are reflected in the database, so inverse only works on the collection, that is, only for One-to-many or many-to-many (because only these two associations contain collections. One-to-one and Many-to-o

The use of foreign keys in MySQL to implement cascade Delete, updateMySQL supports foreign key storage engine only InnoDB, when creating foreign keys,Requires that the parent table must have a corresponding index, and the child table will automatically create the corresponding index when the foreign key is created.When you create an index, you can specify the corresponding action on the child table when the parent table is deleted, updated,Includes re

After we have specified the association mappings for the database tables, when we delete one of them, we prompt the following exception: Deleted object would be re-saved by cascade (remove deleted object from associations ): [Entity. ASSOCIATIONINFORMATION#7](Note: entity.) Associationinformation is the entity class, 7 is the value of the set foreign key)Here's my many-to-one correlation:1. Entity class:Entity. Associationinformation and entity. Assoc

This chapter focuses on some conflicting solutions when an object is extracted multiple times using a style by a selector:1. Specificity: Refers to the final choice when multiple effects are in effect:This rule is compared with 0,0,0,0. Where: inline is the 1,0,0,0 ID selector is the 0,1,0,0 class selector, the property selector and the Pseudo-class: 0,0,1,0 element and pseudo-element: 0,0,0,1The combination and the 0,0,0,0 have no contribution to the particularity, it is theNote: A privilege is

Analysis and functions of MySql foreign key constraints on CASCADE, set null, RESTRICT, and empty types MySql foreign key constraints: NULL, RESTRICT, no action, CASCADE, set null, and other types of analysis and interpretation. Master table, slave table Null, RESTRICT, NO ACTION Delete: The primary table can be deleted only when the table record does not exist. Delete the slave table. The master table

[JAVAEE Study Notes] hibernate03: Multi-table operation details, cascade, link maintenance and exercises: add Contacts, javaeehibernate03 One-to-many | multiple-to-one 1. relationship expression Table expressions 　　 Expressions in entities 　　 Expression in orm metadata One-to-multiple Many-to-one 2. Operation Operation association property // 3 operation Customer c = new Customer (); c. setCust_name ("Chuanzhi podcast"); LinkMan lm1 = new LinkMan ()

The relationship maintenance between tables in Hibernate is the most important, and this is inseparable from cascade and inverse.Table structure: Students and courses are many-to-many relationships, and the third table maps the relationships among the newcomers.Class Structure:Here to save some data:@Testpublic void Save () {Session session = Factory.opensession (); Session.gettransaction (). Begin (); Course Course = new Course (); Course.setcname ("

Php implements a three-level Cascade drop-down box, This is the information on the three-level Cascade drop-down box for php I found on the Internet. Let's share the information and make progress together. The details are as follows: Index. php: Aa. js Get2.php The above is the code for php to implement a three-level Cascade drop-down box. I hope it will be he

Test whether Kettle supports cascade during incremental update-mysql-based bitsCN.com Since LZ is like sorting out how to use Kettle to incrementally update a table, You can also update other tables in the database. The first method is to use a trigger, that is, to add an SQL script step between the corresponding hop and then perform the update operations on other data tables in step. Another method is the timestamp. you can add a time point and then

character corresponds to the binary encoding that appears.In CSS, the weights are as follows: The weight of the label is 1, and the weight of the class selector 10,id the value of the selector is 100.CascadeWhat if there are multiple CSS styles in the HTML file that can exist for the same element and if the multiple CSS styles have the same weights?This is the cascade, as in the following code:The text in the last P is set to green, and the

Annotation method Configuration 1) One-to-many Private list@OneToMany (Cascade =cascadetype.all,mappedby= "T_notice", Targetentity=tnoticeaffix.class)Public listreturn FFI;} 2) One-to-one (one-to-one and one-to-many configurations) Private Ltnoticeaffix FFI;@OneToMany (Cascade =cascadetype.all,mappedby= "T_notice", Targetentity=tnoticeaffix.class)Public Tnoticeaffix Getffi () {return FF

1. Cascade Design ProcessThe general flow of the Cascade design is as follows:The evaluation of the number of cabling layers and the evaluation of the number of power layers will be described in detail in the next article. In this article, we originally wanted to talk about signal reflow and reference plane problems first. But the previous article, found that has been discussed, so this article to do a link

Stm32f103zet6 in a total of 8 timers, including advanced Timers TIM1-TIM5, TIM8, a total of 6. There is a need to use the CASCADE function of the timer, the ST's RM0008 REV12 P388 and P399 page is explained for the specific timer, how to choose the Cascade function, see table 86. Here I output PWM timer is TIM2, idle timer is TIM3. With TIM2 as the main timer, TIM3 counts the number of output pulses from th

Drawing the cascade relationship of a vswitch is the most basic requirement for network O M. Two tables of Layer 2 or Layer 3 switches are involved. One is the ARP table and the other is the MAC address table. The knowledge involved is nothing more than the ARP protocol and the switch (or the bridge) store and forward these two knowledge points. During data transmission, the L2 Switch records the IP address and MAC address of the host that is communi

Oracle cascade operations When you add a foreing key constraint, you can also specify the cascade operation type, which is mainly used to determine how to process the foreign key fields in the subtable When deleting a record in the (on delete) Appendix, there are three types of reference. CascadeThis keyword is used to indicate that when you delete data from referenced columns in the primary table, the valu

When hibernate deletes an association, there will be an eleted object wocould be re-Saved by cascade (remove deleted object from associations) exception. There are usually three solutions based on others' experience: Method 1 Delete the cascade of the set side:Method 2 Delete the link after it is resolved Onside. getmanys (). Remove (thisys ); // Removes the object to be deleted from the associated

Javascript :: $ (Function () {var province = $ ('# province '). comboBox ({valuefield: 'areaid ', textfield: 'name', Editable: false, URL: 'cascade-data. php', onchange: function (newvalue, oldvalue) {$. get ('cascade-data. php', {parentid: newvalue}, function (data) {city. comboBox ("clear "). comboBox ('loaddata', data); County. comboBox ("clear")}, 'json') ;}}); var city =$ ('# City '). comboBox ({valu

Wireless MAC address filtering is an efficient method to prevent wireless network access. However, when multiple routers are connected to the network, you need to set filtering rules on multiple routers, the setting methods vary slightly in different networking modes. This article describes how to set up wireless MAC address filtering for WDS bridging and wired LAN cascade networking.Note:The router management interface is quite different. We will int

= models.ForeignKey(User, blank=True, null=True, on_delete=models.SET_NULL) When the area is deleted, associate other tables with this field and set it to null. In this way, the area record is deleted. Django foreign key tips:* The foreign key is associated with an object. The automatically generated foreign key name is appended with the name of the associated object with "_ id" as the field name.* By default, the foreign key will automatically create an index and perform cascading deletion. T

Date: 2009.05.07 Problem: (1) Use DWR to implement three-layer cascade: function implementation, but the object in JS cannot be converted to the custom object videocateroy (2) query JSP pages: How to Use STR returned by Js for SQL statements 1. Use DWR to implement layer-3 Cascade 1. Expected Implementation Structure Analysis Grade 7 --- Last semester ------- Chinese ------- Mathematics ------- English --