Database Administrator

Oracle Foreign keys only have cascade deletion and no Cascade update, but sometimes such functions may be required in the system, so the implementation process is recorded here. There are two constraints in Oracle: latency constraint and non-latency

Basic Information Database Version: Oracle 10.2.0.4 Number of nodes: 2 1. Stop all processes related to oracle, including databases, asm, node application, and crs.1.1 close all processes, Crs_stop-all 2.2 shut down the crs background process and

1. Create a STRUCT type. Create or replace type STRUCT_TEST as object (NAME VARCHAR2 (50), TITLE VARCHAR2 (30), num number (2 )); 2. Create a STRUCT table and insert STRUCT data. Create table REF_TABLE OF STRUCT_TEST; Insert into REF_TABLE

First, popularize the basic concepts: PL/SQL is a programming Language that combines Procedural Language and Structured Query Language (SQL. The PL/SQL block corresponds to a small piece of code. Applicable instructions: 1. Sometimes you may need to

If the not null restriction is added when VARRAY is defined, the element of this VARRAY cannot be NULL. Definition: Create or replace type integer_varrayAs varray (5) of integer not null;/ Then there is a PLSQL block as follows: DECLARE -- Declare

We all know that the controlfile records information about each archivelog. Of course, after deleting these physical files in the OS The archivelog information is still recorded in the controlfile. the logs are displayed visually in the Oracle OEM

Brief Analysis of Oracle data instance recovery When the database crashes suddenly, such as a sudden power failure or hardware failure, the dirty data blocks in the buffer cache are not written into the data file, and the instance crashes, the

The following is my summary and my understanding about Oracle backup: 1. The data block size in Oracle is usually an integer multiple of the OS block size. The database is always available when the data file is directly copied to the backup media

The control of the ADF is dragged out by VO. Therefore, if you drag the same VO into a Form and a Table on a Page, and implement Association If there is no data in VO: The Table shows no data, while the Form control does not display the outer box of

1. Currently, there is only one control file. We plan to add three to ensure security. SQL> select name from v $ controlfile; NAME -------------------------------------------------------------------------------- + DATA/tyolap/controlfile/current.256

User settingsUlimit-SHn 65535Mkdir-p/home/mysql/infobright/Usr/sbin/groupadd mysql/Usr/sbin/useradd-g mysqlCd/usr/local/soft/Download and decompress64-bit SystemWget http://www.infobright.org/downloads/ice/infobright-3.3.1-x86_64-ice.tar.gzTar zxvf

System: CentOS 5.5 View Log:[Root @ localhost mongo] # tail-20/usr/local/mongo/mongodb. log Mon Sep 19 06:14:55 [initandlisten] MongoDB starting: pid = 4126 port = 27017 dbpath =/usr/local/mongo/data 64-bit Mon Sep 19 06:14:55 [initandlisten] db

Statement for querying deadlock information in Oracle: Select a. owner, A. object_name, B. xidusn, B. xidslot, B. xidsqn, B. session_id, B. oracle_username, B. OS _user_name, B. process, B. locked_mode, C. machine, C. status, C. server,

The latest mysql versions require cmake compilation and installation. It is estimated that this method will be used in future versions. Therefore, we will record the installation steps and procedures for your reference.Note: This installation is the

1. installation environment: OS: Linux x86 CentOS 6.0DB: Oracle11g R1NETWORK: LAN Ii. Installation Steps 1. Check required packagesRun rpm-q to check whether the following packages have been installed and whether the version meets the

The term "View" is too abstract. At first glance, you don't understand what it means, but you don't even know what it means. In fact, you will suddenly realize what it means. The difference between a table and a view is that a table occupies the

My colleague called and told me that the CPU usage of the database is too high and swap is frequently exchanged. I 'd like to take a look at it now. Here, I will record the entire process for your reference and let you provide some comments. $ Topas

Set OperationsUsed to merge results of multiple select statements Union deduplicationUnion all unionIntersect IntersectionMinus difference set UnionMerge set A and Set B, but remove the duplicate parts of the Two Sets and sort them.SCOTT @ ora10g>

Numeric FunctionsROUNDTRUNCMODCEILPowerROUND (column name | expression, n)Rounded to n digits after the decimal pointIdle> select round (458.734, 0), round (458.734, 1), round (458.734,-1) from dual; ROUND (458.734, 0) ROUND (458.734, 1) ROUND (458.7

The following describes how to install the MySQL database: 1. The master and slave servers perform the following operations respectively::1.1 consistent version1.2 initialize the table and start mysql in the background1.3 modify the root password2.