Database Administrator

CentOS MySQL user and database management manual 1. Maintenance of the root user password: After MySQL is installed, MySQL automatically provides a root user without a password. To ensure security, set the password for the root user: # Mysqladmin-u

Oracle random function usage To put it simply, most Oracle random numbers are generated by calling the dbms_random package. There are roughly four methods to generate random numbers through the dbms_random package:1. dbms_random.normalThis function

Steps for building a MongoDB Cluster I have built a mongodb cluster many times, and there will be more or less problems each time. I will write this article for future reference. This is to build a cluster based on mongodb3.0. The steps are as

CentOS6.5 _ 64bit compile and install MySQL-5.6.23 CentOS6.5 _ 64bit compile and install MySQL-5.6.23 1. Disable the FirewallChkconfig iptables offService iptables stop 2. Download The mysqlsource code package and mysql-5.6.23.tar.gzDo not select

Oracle Database Bad blocks-Physical Bad blocks Overview ------------- The types of Bad blocks in the database can be divided into Bad blocks of user data, Bad blocks of Data Dictionary, Undo Bad blocks, and bad blocks of control files according to

Create an ASM instance using an Oracle script Create an ASM instance using an Oracle script Environment: Oracle 11g (11.1.0.6) Windows Server 2003Note: The Oracle asm instance is created before and after 11gR2. Grid infrastructure is introduced in

Five most common access methods for B-tree indexes in Oracle Today, we will discuss the most common B-tree indexes in Oracle databases. First, let's take a look at the structure of B-tree indexes in Oracle databases. We can see that the B-tree

SQL: Composite query in Chapter 14th14.1 Combined Query Most SQL queries only contain a single SELECT statement returned from one or more tables. However, SQL and allow execution of multiple queries (multiple SELECT statements) and return the

Mongo CRUD data operator summary, javascrud Comparison Name Description $ Eq Equal $ Gt Greater $ Gte Greater than or equal $ Lt Less $ Lte Less than or

The SELECT wocould examine more than MAX_JOIN_SIZE rows Error Analysis MYSQL, mysqlnumrowsI used a join table to query a large table with 21 fields and nearly 40 million records. Another table has tens of thousands of records.Error message:#1104 The

SqlHelper reconstruction, sqlhelper SqlHelper (click to View Details) was used during data center reconstruction. At that time, I didn't understand anything. After continuous use, I began to understand the meaning. Later I found that the original

Oracle expdp and impdp command research, oracleexpdpimpdp-- Create a remote data connectionCreate database link DB_MZDB11 connect to YTMZTWO identified by YTMZTWO909 using 'mzdb11 ';-- Create a local directoryCreate directory db_mz as 'C :';--

In case of ins_precomp.mk error when installing oracle12C in LINUX7, the installation tutorial of oracle12c is as follows: Original Works are from the blog of "Deep Blue blog". You are welcome to reprint them. Please note the following source when

Host 'localhost' is not allowed to connect to this MySQL server solution, localhostallowed1. Stop the mysql service first.2. Open a command line window (win + r) and switch to the bin directory of the mysql installation directory. For example, my

[LeetCode] Employees Earning More Than Their Managers, problem solving report, leetcodeearning Directory Directory Question Ideas AC SQL Question The Employee table holds all employees including their managers. Every employee has an Id, and

[Mysql] Mysql 5.1.46 enables the InnoDB engine and 5.1.46innodb As we all know, the default engine of Mysql5.1.46 is Myisam. How can I enable the InnoDB engine? I encountered many errors when installing the database and enabling the InnoDB engine.

MySql learning, mysql learning notesMySql storage engine MySql Databases have many storage engines. Different engines have different features and have their own advantages. I recently read the MySQL technology insider, just taking notes.InnoDB

HBase1.0.0 source code analysis-Request Processing Process Analysis: Put operation as an example (2), hbase1.0.0putHBase1.0.0 source code analysis-Request Processing Process Analysis: Put operation as an example (2) 1. Passmutate(put)Operation to

SDOUG -- Oracle Shandong user group was set up, sdoug -- oracle Shandong About SDOUGSdoug membership program, also known as the Oracle Shandong user group (SDOUG), was jointly launched by GE yunjie, Yang Yunlong, and ban yanliang, it aims to

LeetCode Delete Duplicate Emails, leetcodeduplicate Write a SQL query to delete all duplicate email entries in a table namedPerson, Keeping only unique emails based on its smallest Id. +----+------------------+| Id | Email |+----+--------