Add Column In Mysql

mysql tutorial to modify the table / field to add / delete table index create table test (blob_col blob, index (blob_col (10))); In mysql 5.1, myisam and innodb table prefix can reach 1000 bytes long. Note that the prefix limit should be measured in bytes, while the prefix length in the create table statement is interpreted as the number of characters. Must be considered when specifying the prefix length for columns that use multi-byte character sets. ...

ALTER alter alter the name of the table structure of the name of the table ALTER TABLE ALTER TABLE ALTER TABLE statement is used to add, modify or delete columns in the existing table. sql alter table syntax To add a column to a table, use the following syntax: alter table table_name add column_name datatype To delete a column in a table, use the following syntax: alter table table _...

One, the required installation package apache_1.3.19.tar.gz php-4.0.4.tar.gz mysql-3.23.32.tar.gz Note: The above are source code instead of RPM Package II, Software Installation 1. Install MySQL (1) Unlock the compressed package cd/usr/localtar-zvxf mysql-3.23.32.tar.gz (2) will produce mysql-3.23.32 directory to/usr/local/mys ...

The intermediary transaction SEO diagnoses Taobao guest cloud host Technology Hall recently, the international famous source database manufacturer MySQL's China Research Center and the Tianjin Massive information Technology Limited Company signed the strategic agreement, the massive technology will achieve the MySQL biggest degree localization in China, seizes the Chinese open source database market to provide the formidable help. 　　Because MySQL is a very useful open source database software, its own superior speed, scalability and reliability makes it an indispensable database products. Since the MySQL database can be used in Li ...

Usually when we use the MySQL database, often because of operational errors caused by data loss, MySQL database backup can help us to avoid due to various reasons, data loss or other problems with the database. First, the data backup shortcut Because this method has not been the official official document validation, we tentatively called the experiment. Purpose: Backup hostA host a MySQL database backup TestA, and restored to the hostB machine in the test environment: Operating System: WinNT4.0, Mysql3.22.34, phpM ...

1, use the index to traverse the table faster. The index created by default is a non-clustered index, but sometimes it is not optimal. Under non-clustered indexes, the data is physically stored on the data page. Reasonable index design should be based on the analysis and prediction of various inquiries. In general: a. There are a large number of duplicate values, and often range query (>, <,> =, <=) and order by, group by occurred columns, consider the establishment of cluster index; Column, and each column contains duplicate values ​​can be ...

1, use the index to traverse the table faster. The index created by default is a non-clustered index, but sometimes it is not optimal. Under non-clustered indexes, the data is physically stored on the data page. Reasonable index design should be based on the analysis and prediction of various inquiries. In general: a. A large number of duplicate values, and often range query (>, <,> =, <=) and order by, group by occurred column, consider the establishment of cluster index; b. Column, ...

MySQL is an open source relational database management system, the developer for the Swedish MySQL AB company, is now part of sun company. Oracle announced the acquisition of Sun Company in 2009, so MySQL may become Oracle's products. Because of its high performance, low cost and good reliability, MySQL has become the most popular open source database and is widely used in small and medium Web sites on the Internet. As MySQL matures, it is increasingly used for more large-scale ...

In this lesson, we want to learn how to increase the intelligent processing capacity of the Web page. Basic functions Welcome to the third and final lesson of this tutorial. If you've learned the first and second lessons, you've mastered the basics of installing and programming MySQL and PHP. Here are some of the other functions of PHP that might be useful to you and make your development process simpler. 　　First, let's look at the document. You should know some basic concepts of the header file, right? The header file is an external file whose contents are included in the main program. ...

If a computer manufacturer, its database holds machine and accessories product information. The table used to save the whole product information is called pc; the table used to save the parts supply information is called parts. There is a field in the pc table, used to describe the type of CPU used in this computer; there is a field in the parts table, the description of the CPU model, we can think of it as a list of all CPU models. Obviously, the CPU used by this manufacturer must be a model that exists in the supply information sheet. At this time, two tables ...