Database Administrator

Oracle merge into usage 1. Use of merge Merge is a very useful feature. It is similar to merge into in DB2 and insert into on duplicate key in Mysql. Merge into is a new feature that appears after Oracle 9i. In simple terms, it can be a function of "

ORA-00130: invalid listener address error resolved Log on to the Oracle database. The following message is displayed: Ora11g> sqlplus dcsopen/dcsopen1SQL * Plus: Release 11.2.0.1.0 Production on Mon Jan 5 18:49:31 2015Copyright (c) 1982,200 9,

Oracle modify listening port 1521 In Oracle, the default listening port number is 1521. Once someone scans this port number, it will know that this server is an Oracle database server. This poses an extremely high security risk, how to modify the

Compile and install MySQL in Linux Recently I want to develop Hadoop, install MySQL, and test sqoop. Since MySQL is open source code, install it in source code. The following describes my test environment: VMware10 + Ubuntu14.04 Kylin Next, let's

Install MongoDB 2.6.5 in CentOS 6/Linux MongoDB is a non-relational database (NoSql) that is very popular in the IT industry. Its flexible data storage method is favored by current IT practitioners. MongoDB implements the object-oriented idea. In

Oracle cursor Introduction Oracle cursor Introduction The PL/SQL cursor in Oracle stores the data queried in the database in the memory as a temporary table. The cursor can operate on the data stored in the memory, one or a group of data is returned,

Oracle 11g detailed steps for building a standuard (physical standby all operations) Preface: DataGuard establishes a reference relationship by establishing a PRIMARY and STANDBY group. Once STANDBY is created, DataGuard passes the REDO of the

Procedure for Incomplete recovery across instances based on innobakcupex On the basis of Hot Standby, MySQL can achieve full or incomplete recovery of the original Instance. In many cases, DRBD or MHA is deployed on the original instance. In this

Oracle creates tablespaces and users Oracle creates tablespaces and users 1. Connect to the database# Su-oracle$ Conn/as sysdba 2. Create a tablespaceSQL> create tablespace doiido datafile '/main/oracle/oradata/doiido. dbf' size 1024 M autoextend

Solution to mysql installation failure on Mac, macmysql The version I installed is a mysql-5.6.21-osx10.9-x86_64.dmg that prompts installation failure on Mac OS X 10.10, as shown in. Solution In step 3 of the installation process, select Custom

Oracle CBO evaluates the like data volume, and oraclecbo evaluates like There are two forms of Like Statement, which is evaluated by 5% of the total data volume. SQL> drop table test purge;SQL> create table test as select * from dba_objects; SQL>

Change the version of the dmp file imported from oracle.Today, the customer gave me a table data file exported from the oracle11g database. The file suffix is the dmp file. I imported the dmp file into our business database and reported an error,

SQL assistant-SQL Prompt and SQL assistant promptBackground: When the database design is complex and huge, if we are not very familiar with the script, it will be difficult to complete seemingly simple addition, deletion, modification, and query

Oracle triggers and Oracle triggersOracle triggers A trigger is a special storage process that is automatically triggered by the Oracle system when a database occurs. Triggers are usually used to enhance database integrity constraints and business

SQL optimization -- Logical optimization -- condition simplification, SQL -- 1) query Conditions Query condition concept: In SQL query statements, the expressions used to filter and connect tuples are expressions in the WHERE/JOIN-ON/HAVING

Mysql and Oracle Database concat () functions, oracleconcat I. Different Function Parameters Mysql supports concatenation of multiple strings: CONCAT (str1, str2 ,...) Oralce only supports concatenation of two strings. To splice multiple strings,

In Linux, mysql forgets the root user password, and mysqlrootToday, when receiving a MYSQL server, I found that I forgot the password of the root user of MYSQL. I found that no root user password exists in various documents. Therefore, I need to

SQL server Functions, stored procedures, cursors, nested use of while and if statements, while nesting The main reason for writing this stored procedure is that you are too lazy to write data into the table every day. Not only learning, but also

Oracle SQL optimization set and oraclesql Optimization **************************************** * ******************** 1. create an optimization set object ************************************ * ********************** --- authorize grant administer

Oracle fails to get the index result due to an error. oracle does not get the index. There is a script that has been running for a long time and does not produce any results immediately after optimization. The original statement is as follows: SQL>