Database Administrator

MD5 encryption in Oracle Because MD5 encryption is used, I searched the internet for relevant information and studied it carefully. Its core is the MD5-encoded data packet function: DBMS_OBFUSCATION_TOOLKIT.MD5, which involves the RAW type, which is

MySQL Performance Optimization-Block Nested-Loop Join (BNL) 1. IntroductionI believe that many developers/DBAs are still not satisfied with the way MySQL processes multi-Table associations or the performance when using MySQL. Join queries submitted

New Features of oracle11g-SQL Plan Management (SPM) and oracle11gspm 1. Introduction Oracle Database11gR1 introduces SQL PlanManagement (SPM), a new tool that allows DBA to capture and maintain the optimal execution plan for any SQL statement. This

Check whether the sp called in tidal job is actually running. Just now, the tech leader of us suddenly called me and said that one of the tidal jobs had crashed. Let me help you to find out why And Then rerun got up. At that time, I was dizzy, ask

Mysql lock on the second day, mysql on the second day If there is no lock, the concurrency will be stronger, but the data security will be problematic. Therefore, the database locks the data.Shared lock and exclusive lock That is, the read/write

Oracle BASICS (iii) database management, oracle Basics This article introduces the basic operation commands for Oracle databases: add, delete, modify, and query. The following describes how to manage databases.Database role Introduction Data

Oracle merge query and oracle merge 1). UnionThis operator is used to obtain the union of two result sets. When this operator is used, repeated rows in the result set are automatically removed. 2). union allThis operator is similar to union,

Article Title, article title DaquanNoSQL database product learning Summary (1) This article is divided into four chapters, and will gradually sort out the knowledge of Memcached, Redis, tair, mongodb, hbase, SequoiaDB, and Cassandra. This article

Oracle user management 1. Create a new user (normal)Create user Username identified by passwordFor example, create a user named James with the password xm 2. Change the password of an ordinary user as an administrator (when a common user forgets

Comparison between SQLServer and Oracle: SQLServerOracle I recently went to iron University for an interview. The project leader asked me the following question: what is the difference between SQL Server and Oracle? From entering the software

Summary of common Postgresql ALTER statements, postgresqlalter Postgresql version: psql (9.3.4) 1. Add a columnCopy codeThe Code is as follows:Alter table table_name ADD column_name datatype;2. delete a columnCopy codeThe Code is as follows:Alter

MySQL 5.6 installation-free version (green or decompressed version) to modify the encoding, mysql5.6 See here: http://www.bkjia.com/sjkqy/989251.html It took more than half an hour to try various methods on the Internet. It is estimated that the

Mysql Data File Deletion, operating system level recovery file, mysql level Under what backup conditions is the Data File deleted and restored?Restrictions 1. Do not use data blocks to be restored2. The file system is not damaged. Use tool

Linux Force uninstall mysql, linux Force mysqlIn the case that MySQL cannot be installed in Linux already exists, we can force uninstall it before installing it. steps:1. Find the installed myslq version:# Rpm-q mysqlThe installed mysql package name,

MySQL entry (2), mysql entry For more information about this study, see MySQL required and the official Manual MySQL 5.6 Reference Manual. MySQL (1)MySQL (3)Content:-MySQL join table-MySQL ViewIv. MySQL join table Assume that you want to store the

[Mysql5.6] after the master and slave ip addresses are changed, the synchronization is re-established. mysql5.6ip In this case:Master/Slave System centos6.5 mysql5.6 Because the IP address of the IDC has changed, the original active data cannot

The method for creating a sequence in Mysql. Create table emp_seq (seq VARCHAR (8); insert into emp_seq VALUES ('0'); UPDATE emp_seq SET seq = LAST_INSERT_ID (seq + 1); SELECT LAST_INSERT_ID (); This is exactly the same as the sequence of

The path to oracle Learning (6) two practical examples, the path to oracle1. Simple data insertion example -- Created on 2015/6/15 by LYH declare v_fnumber varchar2 (10): = 'qw'; v_fname varchar2 (10): = 'lyh'; v_fage int: = 10; v_fsalary int: = 101

Msyql TPS v1: Calculate the msyqltps within the specified time Requirement: Calculate the TPS between-during daily business peaks. Idea: 1. records TPS-related historical values at every morning. obtain TPS-related values at any current time minus

MYSQL design optimization and mysql Design This article describes how to optimize mysql from various aspects.1. Optimize SQL statements (1) locate the SQL statements to be optimized (1) count the frequency of SQL statements using show