Database Administrator

The following two system tables are used to query the table where a constraint is located. User_constraints constraints table, which records all constraints of the user. Such as non-null and index. User_cons_columns constraint field table, which

Decompress: Decompress the compressed package and move the bin folder in the extracted folder to/usr/local/mongodb. Create the directory mongodb/data/db and mongo/logs under home/tiantao /. Create a file mongodb. log in logs Use the root user to

Kfed and kfod in CRS_HOME/bin are very useful tools for checking ASM disk. -Bash-2.05b $ kfed-helpAs/mlib ASM Library [asmlib = 'lib']Aun/um AU number to examine or update [AUNUM = number]Aus/z Allocation Unit size in bytes [AUSZ = number]Blkn/um

By default, parallel_max_servers is enabled if it is greater than 0. Alter session enable parallel [ddl | dml | query];Alter session disable parallel [ddl | dml | query];Alter session force parallel ddl parallel 5; Several views used to analyze DB

I. Install the operating system and patch packOnly GNOME Desktop is installed when the operating system is installedYum install gcc-c ++ libXp libaio make binutils openmotif setarch compat-db compat-gcc-c ++ compat-libstdc ++-devel rsh

Environment:The MySQL database version on the master and slave servers is 5.1.34.Host IP: 192.168.0.1Slave IP Address: 192.168.0.2 1. MySQL master server configuration1. Edit the configuration file/etc/my. cnf# Make sure it is as downstreamServer-id

#! /Bin/bash# Function:# Backup user_data# History:# Copyright @ 2011 zhaohaihuaExport extfile = 'date' + % Y % m % d % H % m''Export bak_dir =/home/Oracle/data_bakSu-oracle-c "exp user01/user01 file = $ bak_dir/user01. $ extfile. dmp compress = y

-- Oracle PagingDefined cursor Create or replace package chj1_packageType chjiw.cursor is ref cursor;End chj1_package; -- StepSelect t1. *, rownum from (select * from chengji) t1-- Step 2Select t1. *, rownum rn from (select * from chengji) t1 where

Because the business needs to add a sequence every month, it is expected to use the job to create a regular one year each time. Some problems encountered when writing this job are recorded here. Step 1: Write the stored procedure for creating a

Today, I was about to leave after work. As a result, the developers said that the data in a test table suddenly disappeared and that no one should delete the table, ask me if it is an Oracle Bug (this is a bit of a problem, I can think of it all,

Nesting another SQL statement in an SQL statement is called a subquery. This query statement is used as a condition for another query statement. The SQL statement that contains other SQL statements is called the parent query. Example: If you want to

[Root @ localhost home] # vi test. sh#! /Bin/shOracle_HOME =/oracle/ora10/productExport ORACLE_HOMEUserpwd = test/test@10.11.0.235: 1521/ora10g$ ORACLE_HOME/bin/sqlplus-S $ userpwd Alter session set nls_date_format = 'yyyy-mm-dd hh24: mi: ss

The following prompt message is displayed in the mysql Log file, which is related to the federated engine. This option is added during compilation but is not enabled in the configuration file, for more information about the federated engine, see the

1. explain extended select .....Decompile the execution plan into a SELECT statement and run show warnings to obtain the query statement optimized by the MYSQL optimizer. 2. explain partitions select ....Used to EXPLAIN the Partition Table 3.

Some people ask whether the locks of QueryCache (QC) in MySQL are "global locks" or "Table locks ". Here is a brief description. 1. Basic QC concepts This is a memory structure implemented in the MySQL layer (non-engine layer). The basic rule is to

When the database table size is large and the load is high, it is inevitable that the time consumed by an SQL statement is prolonged. Half a month ago, a scheduled task ran for eight hours in the early morning and suddenly fell helpless. Finally,

Basic concepts of a package A package can organize several functions or stored procedures and store them as an object. A package usually consists of two parts: specification and body ). The program reports can also contain constants and variables.

1. view the size of all tablespaces SQL> select tablespace_name, sum (bytes)/1024/1024 from dba_data_files2 group by tablespace_name; 2. view the idle tablespace sizeSQL> select tablespace_name, sum (bytes)/1024/1024 from dba_free_space2 group by

Enable memory allocation for Oracle databasesTotal System Global Area 389189632 bytesFixed Size 1345156 bytesVariable Size 243272060 bytes 4194304 + 4194304 + 159383552 = 75497472 java_pool large_pool pga_aggregate_target shared_pool_size 243272060-2

Four Common mysql backup tools have their own disadvantages: 0 tarDisadvantage: Hot Backup is not supported. You need to disable the mysqld server before backing up. Mysqld must also be disabled during restoration.1 mysqldumpDisadvantages: MySQL