Database Administrator

Add Constraints SQL> alter table customer add constraint cardunique unique (cardId ); Delete Constraints SQL> alter table customer drop constraint addresscheck; When deleting a primary key, the cascade option must be included. SQL> alter table

When you install or use cx_Oracle, you need to use the connector El library, such as libclntsh. so.10.1. Otherwise, there will be various error messages. After installing the Oracle Instant Client, you can get this link library to Avoid installing a

1. installation: Create bea group and weblogic usersUse root to log on to the operating system and run the following command to create the bea group and weblogic users. Bea group number is 600, weblogic user number is 600, belongs to the bea group,

To obtain a data set from Oracle Procedure, the Ref Cursor method is usually used. To obtain this Cursor, there are several ways: 1. dynamic SQL return: In this case, Procedure operations are usually relatively simple. For example, you can use a

1. about connecting to the Oracle database ①, Normally connected to generate the database Of course, you must connect to Oracle before creating a database. 1. First select the DataBase type: DataBase ---> Choose DataBase: 2. Establish a connection:

This article is a collection of online articles and self-written operations, because there are many problems during the installation process, and it is not as smooth as it is written by others on the Internet, oracle official documentation is the

1. update (select...) set column1 = column2; Update (select iy. company_name company_name1, cc. company_name_jc company_name2From income_year_item iy, city_company ccWhere iy. company_code = cc. code)Set company_name1 = company_name2; 2. Only one

Task: grant the select permission (or insert permission) of all userA tables (or views) to userB. Basic Idea: Log on With usera. select 'Grant insert on' | table_name | 'to userb;' from user_objects; to execute all generated SQL statements. Of

I. Define substitution Variables 1. Set the exact value through DEFINE Define myv = 'King '; The value of the variable myv is King. 2. Define a variable using ACCEPT and prompt you to enter its value Accept myv char prompt 'enter a last name :' The

Question: Why is transaction introduced? 1>. Data Integrity 2>. Data Security 3>. Make full use of system resources to improve the system's concurrent processing capability 1. Transaction Features Transactions have four features: Atomiocity,

1. 1. Create a New Oracle instance; 1, 2. copy and rename the previously installed ArcSDE 9.2 \ ArcSDE \ ora9iexe folder to ora9iexe2 (Path: ArcSDE 9.2 \ ArcSDE \ ora9iexe2). Just set dbinit. ORACLE_SID in sde maps it to the name of the newly

Today, I encountered a lot of problems when installing the MySQL stress testing tool sysbench. Although there are many installation examples on the Internet, they are not accurate enough, or they are not very similar to my own environment, as a

Use the following code in java to query the clob column of db2 (Conn. createStatement (ResultSet. TYPE_SCROLL_INSENSITIVE, resultset.concur_read_only1_cmd.exe cuteQuery (SQL)The following error is reported: DB2 SQL error: SQLCODE:-270, SQLSTATE: 42

In the development of the CS structure system, the package variables in Oracle are often used as global variables of the session. When the operator logs on, the package variables are assigned a value, which can always be taken at any time after this

Mysql does not allow remote connection by default, because it poses a great security risk. You need to manually add users who can remotely access the database. Method 1. log on to mysql locally, change the "host" item in the "user" table in the

Install Oracle10gR2 on Red Hat 4 AS U71. Hardware requirements:========================================================== ===At least MB physical memory# Grep MemTotal/proc/meminfo========================================================== ===Swap

Today, it is also a strange idea. MySQL verifies that varchar (15) will save 15 Chinese characters, and the first 15 will be automatically intercepted if the number exceeds 15. This concept may come from SQL server. In the varchar type, Chinese

A simple method for automatic backup of Oracle databases. Write a batch. The content is as follows: Echo ***** backup start ...******** SetFname = D: \ databak \ %Date:~ 0, 10% Exp system/password @ orcl file = % fname %. dmp owner =

Occasionally, a small BUG occurs when dbms_metadata.get_ddl () is used to capture the SQL statement for creating a TABLE with LOB.The version is 10204.When undo_management is AUTO, LOB storage uses the retention management method by default, but the

I often encounter "Why is my query garbled ?" Or "Why do Chinese characters become garbled after I import it ?" If you want to thoroughly understand the cause, you need to study the Oracle Character Set and the conversion relationship between them,