Database Administrator

Modify the default storage path of MySQL MySQL is a good choice for storing data in Linux. The default storage path of MySQL is/var/lib/mysql. In the past, the database was not very large, with a total size of around 10 Gb, and there was no pressure

Shell batch import MySQL database, batch delete database Due to project collaborative development, my colleague sent an SQL file of the project and opened it in a directory containing hundreds of databases. Each database is used as a separate

Hierarchical relationship of dependency through shell analysis table In normal working environments, there will always be dependencies between some tables. For example, we have three tables: customer, subscriber, and account.The customer can have

Redis full-Memory Operation In some scenarios, we do not need to use Redis persistence. Instead, we need to use redis's memory database feature to achieve full memory operation and high performance. Redis itself supports persistence. By

I have made adjustment configuration items to improve mysql performance, and mysql performance Adjustment Author: fallen flower fragrance Blog: http://blog.csdn.net/qing_gee Preface: I have been studying the configuration items of mysql

SQL Study Notes database topic (2): Development of SQL database under Android, Study Notes for android In Android development, databases are indispensable. In Android development, sqllite is a small embedded database. Today I will write two articles

Oracle XE Installation Guide on CentOS, centosxe Introduction: Installing oracle xe on Centos is mainly used for learning and testing. Although simple, it involves many steps and details. 1. Download Oracle XE Access the

Note the first wave of high-performance mysql, high-performance mysql Author: fallen flower fragrance Blog: http://blog.csdn.net/qing_gee Preface: This article provides some experiences after reading "High Performance mysql. The project has been in

What is the difference between varchar and nvarchar in SQL ?, VarcharnvarcharZookeeper varchar (n)Variable-length and non-Unicode character data with a length of n Bytes. N must be a value between 1 and 8,000. The storage size is the actual length

Two fields in the SQL data table are associated with the same data table. Temp structure of data table -- Table "temp" DDLCREATE TABLE `temp` ( `page_id` bigint(20) DEFAULT NULL, `section_id` bigint(20) DEFAULT NULL, `visit_category_id` bigint(20

The T-SQL determines whether there are (databases, tables, stored procedures, constraints... And column), t-SQL stored procedureDetermine whether a database exists  if DB_ID(N'DATABASENAME') is not null The methods for determining tables, views,

The difference between the three connections and the merger in MS-SQL, Test Platform: MS-SQL 2008 R2; The following two t_a and t_ B tables are used to test join and full join. 1. Create Table create table t_a([aid] [int],[anum] [char]) 2.

Mysql cannot be connected, and the service list does not contain the mysql or mysql list. Today, even though the database cannot be connected, I began to suspect that mysql was not started. Then, enter services. msc in cmd and find it again. The

What are the usage and differences between Decode and nvl functions in Oracle ?, DecodenvlDecode Decode (condition, value 1, translation value 1, value 2, translation value 2 ,..., default Value... else if... else has the same meaningNVL

07. Stack (1) storage structure and operations of stacks, 07 storage structure operationsI. Stack1.Stack): It is a linear table that is only inserted and deleted at the end of the table. The end that allows insertion and deletion is called the top,

08. Application of stack (II) and 08 Application1. Stack application-recursion 1. Recursive Function: Call a function directly or indirectly by calling itself or through a series of call statements, called a recursive function. 2. Stack and

Postgresql data exists in one table, and the other table does not meet the integrity search requirements.There are two tables T1 and T2. The table structure and data are as follows: create table t1 ( id int);create table t2 ( id int, finished int)

Database Optimization-create and classify oracle table partitions, database-oracle When the amount of data in a table increases, the speed of data query slows down, and the performance of applications degrades. In this case, you should consider

Rman recovery from different machines and rman recoveryRman recovery from different machines Note: 1. the directory structure of the source database and target database is the same 2. The target database only needs to install the ORACLE software

Principles and usage of Oracle rownum and oraclerownumFor each row returned by the query, a number is returned using the rownum pseudo column, indicating the order in which oracle selects rows from the table or adds rows. The first row rownum is 1,