Database Administrator

How to Use the MySQL event Scheduler The Event sched feature has been added since MySQL5.1.0. It can be used for scheduled execution of certain tasks and can be seen as a time-based trigger. 1. Enable By default, event scheduling is disabled and

Method 1 for modifying schemas in Oracle Because of service requirements, you need to rename one of schemas. You can find two rename methods after Oracle 11.2.0.2. Method 1: Use the import/export method to modify schemas.• Do a user-level export

B-Tree index and Hash index comparison, B-treehash Understanding the B-tree and hash data structures can help predict the query performance differences of different indexes in different storage engines, especially memory storage engines that allow

An interesting phenomenon: innodb_io_capacity and innodbiocapacity In the past, a customer in the company experienced a situation where sysbench was used for stress testing and a phenomenon occurred during the testing process, as shown below: The

What is the difference between indexes in MyISAM and InnoDB? myisaminnodbTwo small tables, item and category: CREATE TABLE `item` ( `id` mediumint(8) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(150) NOT NULL, `category_id` mediumint(8)

Mybatis delays loading and mybatis delays If you have such a requirement, You need to query all the orders and obtain detailed information about the orders. If all the required data is requested at one time, the overhead on the server and database

First glance at ElasticSearch, elasticsearchFirst glance at the ElasticSearch official website, I don't know what to talk about .. There is a start with on youtube. The content is to run the elastic search under windows, and then use a fidler tool

[Sorting] Summary of common MongoDB commands and common mongodb commands Summary of common MongoDB commands Simple addition, deletion, modification, and query dataSpecify whether to display or not to display a field in the query result. For

Principles and usage of MySql Indexes Original works of Lin bingwen Evankaka. Reprinted please indicate the source http://blog.csdn.net/evankakaI. Index Introduction An index is a structure that sorts the values of one or more columns in a database

Mongodb Study Notes 05 and mongodb Study NotesEnable authentication Mongod does not have the permission to start by default. You need to specify-auth to start, or set security. authorization to "enabled" in the configuration file"Create user Db.

Subscription expiration solution: subscription The Distributed Database executes a long transaction and reaches the 72 hours scheduled by the system.Subscription expiredThe database distribution agent is no longer available. The error message is as

Cainiao's mongoDB learning --- (5) MongoDB's limit, skip, and sort methods, mongodblimit Limit Method If you need to read a specified number of data records in MongoDB, you can use the Limit Method of MongoDB and the limit () method to accept a

Couch MapReduce query, CouchMapReduce 1. MapReduce introduces the traditional relational databases. As long as your data is structured, you can perform any type of query. Apache Couch, in contrast, uses MapReduce (a predefined map and reduce

Update and redoupdate in redoSQL> select * from v $ version where rownum = 1;BANNER--------------------------------------------------------------------------------Oracle Database 11g Enterprise Edition Release 11.2.0.1.0-ProductionSQL>! Uname-Linux

Oracle multi-Table query, oracle Basic multi-Table query syntax The implementation of cartesian products in SQL is not only Cross Join ). All join methods are converted into temporary Cartesian Product tables. Cartesian product is a concept in

Basic MySql knowledge, storage engine and common data types, basic mysql knowledge Original works of Lin bingwen Evankaka. Reprinted please indicate the source http://blog.csdn.net/evankaka This article will mainly explain some basic knowledge about

MySQL Optimization-data type width and mysql Data Type width Reprinted please indicate the source: http://blog.csdn.net/l1028386804/article/details/46559861 You can specify the display width for All Integer Data Types in MYSQL.Create a table

[Translated from mos] Which linker and compiler are used when relink Oracle software is used ?, Relinklinker Which linker and compiler are used when relink Oracle software is used? Reference:Required linker and compiler locations (Document ID 1012798

[Err] 1064, err1064 [Err] 1064-You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near at line 3 This error is prompted when the SQL statement is executed in MySQL 5.6,

Goldengate director installation configuration, goldengatedire GoldenGate ctor installation manual   1. installation environment: 10.100.132.38, redhat 6.4 64-bit   2. Installation check: JRE1.6 is installed, weblogic is installed, and Oracle