Database Administrator

Oracle tree summary -- connect_by_root, oracleconnectby There is a requirement: Count the sales volume of the higher-level department. The manufacturing data is as follows: Drop table dept;Create table dept(DEPTNO number,DEPTNAME varchar2 (50

Insert small details, big problems, insert details, problems The on-site reporting process cannot be viewed today. No data is found in the Process Table. Yesterday, we performed the step of deleting junk data. The general process is: Create table

SQL coding specifications and SQL coding specifications 1. aliases must be created for tables to facilitate the use of columns in the questionnaire. For example, select owner, object_id, name from a, B where a. id = B. id; If you do not use an

Timesten Backup Recovery and timesten backup TtIsql "DSN = ttwind; UID = cacheuser; PWD = cacheuser; OraclePWD = cacheuser ;" -- 1. view the current version Command> versionTimesTen Release 11.2.2.7.0 Command> cachegroups; Cache Group CACHEUSER.

Group by, improve SQL running speed, groupsql Data Table dh_order_detail contains a total of 169247 data records. Original SQL SELECTFROM_UNIXTIME (order_time, '% H: % I') 'time', city, district, LEFT (company, 6) company, goods_num,

Redis (2) advanced features: transactions, redis The first article introduces Redis as a powerful key-value warehouse that supports five flexible data structures. In fact, Redis also supports some other advanced features: transactions, publishing

When Oracle makes adjustments to partitions, add update global indexes and oracleindexes. When you perform ddl operations on a partition, the global index of the partition is invalid. You need to add the keyword update global indexes. SQL> select *

SQL DCL Data Control Language, used to define access permissions and security levels;, sqldcl DCL   1. Create a user * Create user username @ IP address identified by 'Password '; > You can only log on to the specified IP address. * Create user

Checklist, 12 cchecklist installed in oracle 12c grid db Oracle 12c install checklist disable iptables NetworkManager selinuxservice iptables stopchkconfig iptables offservice NetworkManager disable NetworkManager off Modify/etc/selinux/config file

Optimize common oracle SQL statements and oraclesql statements 1. execution efficiency caused * Minimize the use of select * For queries. When you use * For queries *,The database parses and converts * to all columns. Select count (si.

Getting started with MongoDB (installation and configuration)I. Introduction A non-relational database (NoSql), MongoDB is a powerful, flexible, and Scalable Data Storage Method. Because MongoDB is a document model, it is highly flexible and

MySQL Database Management (2) Installation of MySQL Cluster in a single-host environment, mysqlcluster AboveMySQL Database Management (1) MySQL Cluster IntroductionThis article briefly introduces the MySQL Cluster. We will teach you how to build a

MySQL server connection process analysis, mysql server process Mysqld is the master process on the MySQL server. It can be said that mysqld is the real core of MySQL, and all work is carried out around the mysqld process. Therefore, mysqld code is

Mysql permission ControlOverview Mysql permission control can be controlled in different contexts and different operation levels. They include the following:**Management permissions allow users to manage mysql server operations. These permission

MySQL innodb Engine analysis (initialization), mysqlinnodb MySQL's storage engine works in the form of plug-ins. This should be a major feature of MySQL! According to the deep understanding of MySQL, the plug-ins of the storage engine in version 5

Oracle mobile table, oracle mobileOracle mobile tableWhen creating a table, you can specify a storage space for the table. If not specified, oracle will store the table to the default tablespace. You can move a table from one tablespace to another

SQLServer network protocol (I), sqlserver network protocol Currently, SQLserver has three main Protocols: Shared Memory, TCP/IP, and Named Pipe.   SharedMemory: Shared Memory is the fastest and simplest protocol. Clients using the SharedMemory

MySQL database optimization and mysql database Optimization For a data-centric application, the quality of the database directly affects the performance of the program, so the database performance is crucial. In general, to ensure database

MySQL string function, mysql stringString case-sensitive Conversion MySQL string case-sensitive conversion functions include lower (), uppper (), lcase (), and ucase () mysql> select lower('DDD');+--------------+| lower('DDD') |+--------------+| ddd

Common MYSQL commands and common MYSQL commandsStart: net start mySql;Enter: mysql-u root-p/mysql-h localhost-u root-p databaseName;List databases: show databases;Select Database: use databaseName;List tables: show tables;Show columns from tableName;