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1.sql①t_orderitem a foreign keyBname: Convenient late book deletionCREATE TABLE ' T_orderitem ' ( ' Orderitemid ' char (+) NOT null, ' quantity ' int (one) DEFAULT NULL, ' subtotal ' Decimal (8,2) default NULL, ' bid ' char (+) default null, '

1. Build a tableCreate table of Level two classifications: ' CREATE TABLE ' Categorysecond ' (' CSID ' int (one) not null auto_increment, ' csname ' varchar (255) DEFAULT NULL, ' C ID ' int (one) DEFAULT NULL, PRIMARY key (' CSID '), key ' fk936fcaf2

[JAVAWEB learning notes] online mall Practice 3: shopping module and order module, javaweb learning notesOnline mall Practice 3 Today's task Complete the functions of the shopping module Complete the order module function 1.1 shopping module: 1.1.

Mysql triggers are used in PHP projects for information backup, recovery, and clearing. mysql triggers Case: You can use the PHP background code to delete employee information and restore deleted employee information (similar to recovering employee

Online mall 7-order module, online mall 7-order 1. Create a table: CREATE TABLE `orders` ( `oid` int(11) NOT NULL AUTO_INCREMENT, `total` double DEFAULT NULL, `ordertime` datetime DEFAULT NULL, `state` int(11) DEFAULT NULL, `name` varchar(20)

Configuring the Yum source CentOS 7 configuration Yum Sourcehttp://mirror.centos.org/centos/7/http://mirror.centos.org/centos/$releasever/os/$basearch/$releasever $basearch indicate the operating system version and the number of bits, Yum recognizes

Case: The PHP backend code allows the employee's information to be deleted, the deleted employee information will be restored (similar to recovering employee information from the Recycle Bin), and the deleted employee can also be emptied (similar to

Brief introduction of MSQL data type 1, integer typetinyint, accounted for 1 bytes, signed: -128~127, unsigned bit: 0~255smallint, accounted for 2 bytes, signed: -32768~32767 unsigned bit: 0~65535Mediumint is 3 bytes, signed: -8388608~8388607,

The default setting method for datetime type in mysql, mysqldatetime An error occurred while modifying the default datetime value through the navicat client. The field type of the database table is datetime. The default value is NULL. When the

If a large table contains millions, tens of millions, or even hundreds of millions of data records, the query results should be queried in real time within 10 seconds. What should I do? How to optimize it? In my current project, there is a table

If you are not interested in the long article, you can also look at the results directly. Maybe you are interested in the results. In practical applications, after storage and optimization, the query response speed can be controlled within 1 to 20

Mysql auto-incrementing column leads to duplicate primary key issue analysis..., mysql primary key A few days ago, the development of shoes reported a problem of using the load data infile command to import data primary key conflicts. After analysis,

This article light blueSome time ago someone sent the source of cloud search, it has been a long time.I'm releasing the newest one this time.is the source code before he changed the template. (Now the search cloud back end basically no change

If a large table contains millions, tens of millions, or even hundreds of millions of data records, the query results should be queried in real time within 10 seconds. What should I do? How to optimize it? In my current project, there is a table

Present situation:Read the previous article, the landlord uses Python, so in the building test report this piece is used Unittest+htmltestrunner, and then found that the generated report, there is always so imperfect place, such as want to add

First look at the effect chart: 1.sql ①t_orderitem a foreign key Bname: Convenient late book deletion CREATE TABLE ' T_orderitem ' ( ' Orderitemid ' char () not NULL, ' quantity ' int (one) DEFAULT null, ' subtotal ' Decimal (8,2)

first about the relationship between tables and tables 1. A One-to-many2. A One-to-many3. Multiple to One4. Multi-pair multi- parent table and child table 1. "One" is the parent table2. One side of "many" is how a child table handles a one-to-many

! [] (D0a593ed-64a4-495e-99a6-1efa11014eca_files/b013acf0-4402-4e22-bfda-5993df97257d.png)# # Database1. Save a fixed 30 IMEI Testimeis for testing```CREATE TABLE ' Testimeis ' (' IMEIs ' VARCHAR (+) DEFAULT NULL) Engine=innodb DEFAULT

Case: The PHP backend code allows the employee's information to be deleted, the deleted employee information will be restored (similar to recovering employee information from the Recycle Bin), and the deleted employee can also be emptied (similar to

Whether it is a newly graduated college students or have been in the field of software for many years of veteran, as long as the mention of DELETE data SQL Statement No one knows no one, then talk about the deletion of the SQL statement is showing