Database Administrator

Install and verify memcached and memcached 1. Install libevent Down: http://www.monkey.org My online drive down: http://pan.baidu.com/s/1qW8syZi [Root @ luozhonghua memcachedsource] # tar-zxvf libevent-1.4.13-stable.tar.gz [Root @ luozhonghua

MySQL calculation field, mysql Field Calculated Field The tables in the database are stored by columns, but sometimes the information the client wants is a combination of several columns or the sum value. This combination or summation action can

Typical Oracle query Cases 1. Create a student management database named student2. At least three tables are contained.S (SNO, SNAME) Student Relationship. SNO is the student ID, and SNAME is the nameC (CNO, CNAME, CTEACHER) Course relationship. CNO

1. The first type of repetition is easy to solve. The methods in different database environments are similar:Reference content is as follows:MysqlCreate table tmp select distinct * from tableName;Drop table tableName;Create table tableName select *

Database naming rules 1Purpose Standardizes naming rules for various objects in the database. 2Database naming principles 2.1Data Files If the database uses a file system instead of a bare device, the following naming rules are agreed: 1) Data

Next, after the resolution of SCN problem, encountered ORA-600 [4194]/[4193] error.Fault symptom: An error is reported when you OPEN the database:ORA-00600: internal error code, arguments: [4194], [], [], [], [], [], [], [] 4193: indicates

Required bytes 1 ASCIISTR Format:ASCIISTR (C) Note:Converts a string C to an ASCII string, meaning that the ASCII characters in C remain unchanged, but non-ASCII characters are returned in ASCII format. Example: SQL> select asciistr ('AB? CDE

 PAC cost update Transaction ProcessingDECLARE l_itfs_rec mtl_transactions_interface % ROWTYPE; BEGIN-- Insert interface tableSELECT mtl_material_transactions_s.nextval INTO l_txn_header_id FROM dual;V_date: = p_end_date-1 | '06:00:00 '; l_end_date:

In the process of software development, the scalability of the system has been noticed from beginning to end, but at the same time, the system performance is also concerned. As a part of the system performance, SQL statements cannot be ignored,

1.1.1. HA: inconsistent GTID_MODE configurations [Environment description] Msyql5.6.14 [Error message] In the initial state, both the Master and Slave enforce-gtid-consistency and gtid-mode are enabled, and both of them are changed to off. In

1. The first connection string connecting to SQL SERVER: For the database Authentication Mode "SQL SERVER and windows, The connection string is: CString strConn; StrConn = "Provider = SQLOLEDB.1 ;\ Persist Security Info = true ;\ User ID = sa

29. Which two statements are true regarding constraints? (Choose two .)A. A foreign key cannot contain NULL values.B. The column with a UNIQUE constraint can store NULLS.C. A constraint is enforced only for an INSERT operation on a table.D. You can

MYSQL contains Blob fields, which is inconvenient to export and import. I will introduce how I did it. 1. Add a line at the end of MYSQL my. ini to configure max_allowed_packet = 100 M and restart the MYSQL service. Set the size of this value

13. View the Exhibit and examine the structure of the PRODUCTS table. You need to generate a report in the following format:CATEGORIES5MP Digital Photo Camera's category is PhotoY Box's category is ElectronicsEnvoy Ambassador's category is

View background When I first started charging the data center, the master said that they should use the view, storage process, and trigger. I didn't feel much at the time, I don't know when to use it, and where to use it. Just a few days ago, when I

Select count (*) from (select. * FROM (select cd. *, nvl (CV. SUM_CI_BALANCE, 0) as SUM_CI_BALANCE, nvl (CV. SUM_LN_BALANCE, 0) as SUM_LN_BALANCE FROM OCRM_F_CI_CUST_DESC CD left join (select cust_id, FR_ID, sum (CI_BALANCE) as sum_CI_BALANCE, sum

1. Types of SQL parse SQL parse is usually divided into hard parsing and soft parsing. When SQL is executed for the first time, hard parsing will occur, and subsequent execution will be soft parsing if it can be found in the shared pool. Therefore,

1. What is NULL?NULL indicates UNKNOW (unknown), which does not represent any value. For example, if a column in a row does not have any value, it is NULL.ORACLE allows blank fields of any data type, except for the following two cases:1) primary key

Common Character sets include ASCII, GB2312, GBK, UTF-8, Unicode First, you must know ASCII code: One byte is used to identify 0-9 numbers, uppercase and lowercase letters, and some punctuation and invisible characters. 1 byte, 8 bits, can have 256

The script is updated again and shared!     #! /Bin/sh## Usage:#./Restore. sh/full path of your backup file# Ocpyang@126.com INNOBACKUPEX = innobackupexINNOBACKUPEX_PATH =/usr/bin/$ INNOBACKUPEXTMP_LOG = "/var/log/restore. $. log"MY_CNF