Oracle

Oracle switches undo tablespace 1. create an undo tablespace SQL> create undo tablespace undotbs2 datafile 'e: \ oracle \ product \ oradata \ orcl \ un dotbs02.dbf' size 10 M autoextend on next 10 M maxsize 500 M; 2. since undo_tablespace is a

Oracle SQL creates a valid index to reduce the number of returned tables: in data, when querying data, search for the index to obtain the rowid of the row, and then query the data in the table based on the rowid, is the return table. In a database,

Oracle 11g x64 Oracle SQL Developer error: Unable .. SQL developer is always difficult to learn about oracle over the past few days. This time, it is finally solved. oracle SQL Developer error: Unable to find a Java Virtual Machine 1. environment

Database Query example and SQL statement [SQL] drop database if exists SS; create database SS; www.2cto.com use SS; create table Student (Sno char (9) primary key, sname char (20) unique, Ssex char (2), Sage smallint, Sdept char (20); create table

Oracle 11gR2 on CentOS to create a database 1. tmpfs configuration tmpfs is half of the memory by default. If only Oracle is installed on CentOS for database server usage, you want to set Oracle AMM to use 80% ~ 90% of memory, must be set to large

How to locate what you don't know: especially to know which view to query. If I want to check what is related to role, I rely on dba_objects, so: SQL> select object_name from dba_objects where object_name like '% ROLE %'; www.2cto.com OBJECT_NAME

Change the port number C: \ Documents ents and Settings \ hesai> sqlplus SQL * Plus: Release 10.1.0.2.0-Production on Saturday October 20 15:16:37 8080 Copyright (c) 2012 4, ORACLE. all rights reserved. www.2cto.com Enter user-name:/as sysdba

Create an oracle database instance in linux. 1. Open a terminal on the GUI of the Linux server and enter the following command. xhost + 2. Switch to the oracle user and run the following command: su-oracle3. Specify the variables and values of the

Create a synonym in Oracle create a synonym statement in Oracle: we all know that user management in oracle uses permission management, that is, if we want to use a database, we must have permissions, but if someone grants us the permissions, we can

Oracle query does not repeat multiple columns of SQL statements. In Oracle, it is required to query t in the customer table. address, t. customer_name does not repeat columns: the general idea is: SQL code select distinct t. address, t.

Oracle Record type Introduction 1. What is Record )? A composite structure composed of scalar values of multiple columns in a single row. It can be seen as a user-defined data type. It is similar to a multi-dimensional array. Encapsulate one or more

After the ORACLE NLS_CHARACTERSET Character Set Change database is created, if you need to modify the character set, you usually need to recreate the database and convert it by importing and exporting. You can also change alter database character

Differences between on and where in left join of Oracle databases when two or more tables are connected to return records, an intermediate temporary table is generated, then, return the temporary table to the user. When left jion is used, the on and

Oracle syntax memo loop oracle loop statement loop while for test use table SQL code create table hadoop_param (name varchar2 (255), num int) www.2cto.com SQL code declare v_name varchar2 (255 ); v_num int; v_pos int; begin v_pos: = 0; loop exit

There are only two basic ways to access oracle Data: Full scan or index scan. Statistics play a key role in the preparation of the optimizer to determine the optimal method. Www.2cto.com when a full scan is performed on an object, all data blocks

Differences between analyze and dbms_stats functions collect statistical information as follows: SQL code select table_name, num_rows, blocks, avg_row_len from user_tables where table_name = 'T '; www.2cto.com SQL code analyze table t compute

In terms of Oracle partitioning and performance analysis, we perform Table Partitioning to improve performance and speed up query. However, sometimes the query speed is not accelerated, but slowed down. The example below is as follows: www.2cto.com

Oracle reported ora-01033: oracle initializationg or shutdown in SS error found problem customer Oracle Server entering PL/SQL Developer times ora-01033: oracle initializationg or shutdown in progress error prompt, application system cannot connect

Oracle database link connects to different database platforms in mssql, which is generally called a heterogeneous database service. Different vendors have different implementation technologies: in SQL SERVER, it is called a LINKED SERVER, use ODBC

For more information about the import and export of oracle statistics, see the official oracle documentation. 1. database version: SQL> select * from v $ version 2/BANNER Release Oracle Database 10g Enterprise Edition Release 10.2.0.4.0-64bi PL/SQL