Oracle

In practice, you often encounter the need to periodically delete data that has expired and release server resources. For example, we define a timer task, which starts at 2 o'clock in the morning, and this task is to delete data from 1 months ago to

Paged Query format: SELECT * FROM (select A.*, ROWNUM rn from (SELECT * FROM table_name) A where ROWNUM = 21 The most internal query, select * FROM table_name, represents the original query statement without paging.

http://pan.baidu.com/share/link?shareid=3782452820&uk=3557941237http://pan.baidu.com/share/link?shareid=3768883331&uk=3557941237Http://jingyan.baidu.com/article/fb48e8be4c7c206e622e1491.htmlHttp://wenku.baidu.com/link?url=YLtW_2nS0D14YiHbEo5NWRCDMQhK

The installation process for Red Hat Enterprise Linux 7.1 was introduced in the previous article, with minimal installation.See http://xdwqs.blog.51cto.com/4758880/1621643Oracle Enterprise Linux is a company-class Linux distribution supported by

SqoopIn simple terms, the data transfer between the relational database and HDFs can be realized.Most of the test data is based on the MySQL implementationBut there was a problem while testing the connection to Oracle.Error One: Connectivity issues,

---create GroupGroupadd OinstallGroupadd dbaGroupadd Oper------Create UserUseradd-g oinstall-g dba,oper-d/export/home/oracle-m-s/usr/bin/bash Oracle----Create the Oracle ' s directoryMkdir-p/u01/app/oracle/product/11.2.0/db_1Chown-r

Truncate in OracleSyntax: TRUNCATE table table;You can delete all records in a table by using the TRUNCATE statement (DDL language). When you use the TRUNCATE statement to delete data, it is usually much faster than using the DELETE statement

Quickly insert million data in Oracle Create a table   Create table TX_TEST (id number not null, NAME VARCHAR2 (200), URL VARCHAR2 (300), POSITION VARCHAR2 (200), createtime date) Write scripts     Declare -- Local variables here count

Oracle using KeywordOracle using KeywordThe SQL/92 standard can use the using keyword to simplify the connection query, but only when the query meets the following two conditionsSimplify with the using keyword.1. the query must be an equijoin.2.

Oracle connection typeIf you connect multiple tables by using the select clause and the from clause, the query result is a table generated by the Cartesian product.The table generated by the so-called flute product is the table generated when each

Synchronize tables using materialized views in oracle Table synchronization can be implemented using materialized views, which can be performed between different databases in the same database or database. We recommend that you use real-time

Truncate usage in oracleTruncate in oracleSyntax: truncate table;You can use the truncate Statement (DDL language) to delete all records in a table. The truncate statement is usually much faster to delete data than to delete data. This is because no

Solaris User and file permission management, solaris permission management This article was re-published to zhuxuekui3 at 20:45:28 Solaris User and File Permission Management 1     Category "website category" Oracle   1. User and User Group

Oracle Metadata, oraclemetadata Http://www.devart.com/dotconnect/oracle/articles/metadata.htmlHttp://dcx.sybase.com/1101/en/dbprogramming_en11/ianywhere-data-sqlanywhere-saconnection-getschem6330755502-0.html In this overload first parameter is name

Oracle cascade operationsWhen you add a foreing key constraint, you can also specify the cascade operation type, which is mainly used to determine how to process the foreign key fields in the subtable When deleting a record in the (on delete)

About the system permission of sysoper in Oracle We all know that after the Oracle database is installed, there will be several system roles or permissions by default, such as nomal, sysdba, and sysoper. Each time we log on to Oracle, they all log

Oracle12c learning 3 converting nocdb to pdb 01:23:06 sys @ orcl> select name, decode (cdb, 'yes', 'multitenant Option enabled', 'regular 12c Database: ') "Multitenant Option", open_mode, con_id from v $ database; NAME Multitenant Option OPEN_MODE

Primary Key constraints of oracleA primary key constraint is a primary key constraint used to uniquely identify a row of records. Only one primary key constraint can be defined in a table. This constraint can be defined on Individual columns or

Oracle tree summary -- connect_by_root There is a requirement: Count the sales volume of the higher-level department. The manufacturing data is as follows: Drop table dept; create table dept (DEPTNO number, DEPTNAME varchar2 (50), PARENT_DEPTNO

Optimize common oracle SQL statements 1. execution efficiency caused * Minimize the use of select * For queries. When you use * For queries *,The database parses and converts * to all columns. Select count (si. student_id)From Student_info si