Database Administrator

Restrictions on table space that can be transferred: The table space technology cannot be applied to system tablespaces or objects owned by sys users. In the transmission tablespace, The tablespace must be self-contained. The self-contained table

Because of historical and Encoding Problems (garbled characters ). Garbled characters are found in the generated database SQL file, which isolates some single quotes, leading to syntax errors. Client software such as SQLYog cannot be restored. You

The database is Oracle 9i 1. Export a csv file This is very simple. You can use the pl/SQL tool. First, select the table to be exported, right-click Query data, and in the window that appears on the left, select Export Query Restls and select the

--------------------------------- --Create a new user --------------------------------- Create user hahaya Identified by hahaya Default tablespace users Temporary tablespace temp; --------------------------------- --ToHahayaUser authorization -------

Join query category in SQL2 (1) Cartesian product | cross join: unconditional join. The result is the product of the number of two link element groups. [From] cross join (2) Natural join: equivalent join based on all public attributes. The result

[1] Remove the statements in the script including commit, "setserverout off", "set serverout on", "set escape on", and "exec ". [2] Remove "/" [3] it is best to use "separator" + "line feed" for statement separators, for example: ALTER

1Syntax 1.1Row-Level Definition   1.2Table-Level Definition       2NOT NULL Row-level definition only. SQL> create table tn0 (a number (4) not null, B varchar2 (20 )); SQL> create table tn1 (a number (4) constraint nn_tn1_a not null, B varchar2 (

1UseSQL * PLUSStop Database 1.1Stop an instance Oracle@www.bkjia.com ~ $ Sqlplus/nolog SQL * Plus: Release 10.2.0.1.0-Production onWednesday6Month11 17:53:02 2008 Copyright (c) 1982,200 5, oracle. All rights reserved. SQL> conn/as

When writing a java program in Linux, the problem of displaying or inserting MySQL database garbled characters is solved: To solve this problem, you only need to add: & Amp; useUnicode = true & characterEncoding = gbk As shown below  

Hidden parameters are used internally by 0racle and start.You can view all hidden parameters in the following two ways: SELECTI. ksppinmName, I. ksppdesc description, CV. ksppstvl VALUE, CV. ksppstdf isdefault, DECODE (BITAND (CV. ksppstvf, 7 )

During application development, it is common to sort data according to certain rules and then retrieve the first few data records. In Oracle, order by is commonly used to obtain data smaller than rownum. However, if you are not familiar with Oracle,

1. TRUNC Function 1. TRUNC (for dates) The date value intercepted by the TRUNC function for the specified element.The syntax format is as follows:TRUNC (date [, fmt])Where:Date: A date value.Fmt date format, which is truncated by the specified

To increase the query speed, generally: 1.Create a primary key for fields that do not need to be deleted; create an index for fields that may be deleted. 2. If you submit 5 million numbers at a time, each of them must be compared with the 90 million

1: difference between implicit cursor and display cursor * No need to declare a cursor * No need to open or close the cursor * The INTO clause must be used. Only one INTO clause can be returned.   2: Similarities between an implicit cursor and a

1. By default, no segment is assigned to the empty table at Oracle11g. Therefore, when you use exp to export the Oracle11g database, the empty table is not exported. 2. After the deferred_segment_creation parameter is set to FALSE, segment is

Understand Oracle, create users, and understand data types! Goal: Understand the orale Database I. Data Types in Oracle: Number Type: A) number indicates the number type, but if there is a decimal number, it must be written as follows: number

[Root @ rac1 ~] #/Etc/init. d/Oracleasm configureProcessing the Oracle ASM library driver. This will configure the on-boot properties of the Oracle ASM libraryDriver. The following questions will determine whether the driver isLoaded on boot and

The database instance is disabled.Startup nomount database instance starts to the First Stage (Steps:1. Search for the parameter file spfile . ora. If no, search for spfile. ora. If no, find init . ora.2. Allocate SGA3. Start the background process4.

(1) multiple databases can be configured in Oracle, and only one listener can be enabled. You only need to configure the corresponding service name (for example) for multiple databases to connect. Note the following points:1. generally, if multiple

ORA-12154 TNS cannot parse the specified connection identifier. This error is reported today when the database suddenly connects, plsql connection fails, application connection fails, but SQL can be connected. I searched for it online for half a day