Database Administrator

Be careful when using with in Oracle -- predicate cannot be promoted Today, we can see that a SQL statement uses with in large quantities. For logic clarity, developers cache some result sets first with, and there are many places to use this result

Oracle analysis function PERCENTILE_CONT Query the salaries of people with the salary distribution of 25%, 50%, and 75% in each department. percent_rank () is the relative position in the ranking. Create table EMP(Empno number (4) not null,ENAME

ORA-28000: the account is locked resolved In Oracle, if the account fails to log on for ten consecutive attempts, the account will be locked ). When you log on with a locked account, the system reports an error: ORA-28000: the account is locked.

Alex's Hadoop rookie Tutorial: 8th Sqoop1 installation/import/export tutorial, hadoopsqoop1 Depend! Sqoop2 has too few documents and does not support Hbase, which is very simple. So I gave up Sqoop2 and switched it to Sqoop1. I followed my tutorial

MySQL InnoDB Storage engine table (2), mysqlinnodb This article continues the unfinished part of the previous article. 4. InnoDB Data Page StructurePage is the minimum disk unit for the InnoDB Storage engine to manage databases. A page of B-tree

The node solution is not visible when the database software runInstaller is installed in RAC. racruninstaller     Clusterware is installed normally, but runInstaller cannot see the node information when installing Oracle software:   [Grid @ rac1

Optimization of SQL statements in hybrid MySQL, effectivemysqlWe recommend that you optimize SQL statements in objective MySQL.This article mainly explains how to analyze SQL Performance, indexing principles, how to create appropriate indexes, and

Solution for ORA-01417 under Oracle 11g, 11gora-01417 Today there is a brother feedback, there is a SQL on 12C no problem, on 11G on the error, the error content is ORA-01417: The table can be externally connected to at most one other table. This

Firebird Database On MacOSX, firebirdmacosxFirebird Database Firebird, as an excellent embedded (one function), is most suitable for desktop development. I have also used SQLITE to do some gadgets before, but it does not perform well in terms of

Oracle set feedback, oraclefeedback 1. set feedback on Oracle will give feedback when an SQL statement is sent by default.For example, execute the following table creation statement: Create table t_test_lll (id varchar2 (10 )); The command line

How to sort reports in a report group and report During report development, you will often encounter reports that require unconventional statistics, including preset grouping, repeatable grouping, and intra-group sorting, as well as reports computed

Implement POSTGRESQL cross tabulationHere I will demonstrate how to implement cross-tabulation display in POSTGRESQL. As for what a cross-tabulation is, I will not talk much about it.The raw table data is as follows: t_girl=# select * from score;

Several Methods for SQL optimization and SQL Optimization 1. Create views of commonly used data to minimize query methods such as group by, order by, and update; 2. Establish a reasonable index; 3. Select and project first, and then connect

Skip or not? This is a problem, jump or problemOn Monday (), a project was changed, which was a major change. The database test operation continued from morning till seventeen o'clock P.M., and QA colleagues found that, the data on the slave is

The "APPLY security settings error" solution appears during MySQL installation. mysqlapply **************************************** ****************************************************** Original works, from the "Xiaofeng residual month xj" blog,

When oracle Session is locked, oraclesession A problem often occurs. A table in oracle cannot be updated suddenly, either through pl/SQL Developer or through sqlplus, the execution of the update statement or the execution of the select * from table_

GRANT authorization, grant authorization Log On As the sys (Administrator) and create the username zsta_new Create user zsta_newIdentified by passwordDefault tablespace ZSTA_DATA_TBSTemporary tablespace TEMPProfile DEFAULT; Authorize zsta_new users

Java method for accessing mysql database, javamysql Database 1. Download the interface package mysql-connector-java-5.0.8-bin.jar 2. Programming (1) load the driver (2) programming connection operations (3) return result Processing Programming

Mysql replication principle and Function Analysis (), mysql2014-11-11Replication Principle 1. The master writes data to the binlog. 2. slave enables two threads: I/O thread and SQL thread. 3. The slave I/O thread connects to the master and reads the

Oradebug promotes scn and oradebugscnSometimes we encounter the following errors: ORA-01092: ORACLE instance terminated. Disconnection forcedORA-00600: internal error code, arguments: [2662], [0], [5685940], [0], [5685970], [4194432], [], [], [], [],