Oracle

The common case is that a table with a primary key can be a unique form of knowledge. We are able to use the primary key and rownum mates to implement. Like what:select scott.emp.* from scott.emp left join (select empno id, rownum num from

http://blog.csdn.net/doudou_demo/article/details/476667511, open Plsql, fill in the User name and password (the initial two user sys and system, the password is set by the Oracle database installation), database select ORCL (default database, Oracle

ETL in the last one weeks whether in the early morning or at noon job execution process often stuck, resulting in the failure to complete the system engine running, the business impact.By generating the AWR report, it was found that three SQL

Operating EnvironmentSuSE11 + ORACLE11GR2 (11.2.0.3)problem PhenomenonNew Installation of Oracle boot failure, prompting for ORA-01078 and LRM-00109 errors. Specific error phenomena are as followsProblem analysisBased on error analysis, the failure

The use of rownumSelect Rownum,empno,ename,job from emp where rownumYou can get value data that is less than 6Select Rownum,empno,ename,job from emp where rownum>6 and rownumNo data reason: Oracle first produces a number of 1 data, that is, the

SQL statements are divided into 3 categories1.ddl:data definition Language, data definition language,The language used to define and manage all objects in the SQL database1.CREATE creation2.ALTER modification3.DROP Delete5.COMMENT comments6.GRANT

What Dblink connections are queried in the databaseSELECT * from dba_objects where object_type= ' DATABASE LINK ';Delete a public emis_productoin connectionDrop public database link emis_production;Create a public emis_production connectionCreate

1. Download the installation packageHttp://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.htmlOracle-instantclient11.2-basic-11.2.0.1.0-1.x86_64.zipOracle-instantclient11.2-sdk-11.2.0.1.0-1.x86_64.zipOracle-instantclient11.2-sqlplus-11.2.0.

For computers with limited configuration, it is not necessary to use Plsql to install Oracle.First, download a instantclient (a lighter-weight customer package provided by Oracle)It is said that Plsql does not support 64-bit instantclient.Attached

ADO Operation Oracle database is basically the same as the original operation of MSSQL. Just use a different namespace. Here are two examples:One. C # Read the table for Oracle database ///ADO Read Table///you need to add a namespace: Using

The *order by clause at the end of the SELECT statement.Use an outer join to query data that does not meet the join criteriaWith clause character function Lowerupperinitcap concatsubstrlengthinstrlpad/rpadtrimreplace number function

1. Constraint IntroductionAlthough the table is completed, the data in the table is not valid, and if you want to do some filtering on the data in the table, you can do it through the constraints, the main function of the constraint is to ensure

The JDBC Connection database process is:1, load driver, establish connection2, creating the SQL statement object3, Execute SQL statement4, processing result sets5, close the connectionThese five steps are about 4 major points of knowledge:1, Drive

1. Table SpaceA database can have more than one table space, and a table space can have more than one table. A tablespace is a physical space to store multiple tables, and you can specify the size and location of the table space.1.1 Creating Table

SELECT * from Stuent;ALTER TABLE student Add Stu_card char (18)--PRIMARY KEY constraint: Non-null, unique PRIMARY keyALTER TABLE student ADD constraintPk_stuid primary KEY (STU_ID)--Check the constrained check ck_xxxALTER TABLE student ADD

After the configuration is complete, switch to the Oracle User:Su-oracleExecuting the tnsping service name (SERVICE_NAME), under Oracle User, refers to the service_name in the Tnsname file.If OK appears later, it indicates that TNS is normal. As

Uninstall steps: 1. Stop all Oracle Services2. Running Oracle Universal Installer uninstalling Oracle3. Modify the registry to remove Oracle-related information? Oracle software has key-value hkey_local_machine\software\oracle? Oracle Service

First, the use of the environmentOperating system: CentOS Release 6.2 (Final)Database: Oracle 12gDatabase home directory:/ora12/product/product/12.1.0/db_1Ii. Description of the problemAfter logging in to sqlplus with the SYS user, prompt when

I. Databases (database, DB)Database Management System, DBMSDatabase administrator (db Administrator, DBA)Database systems (DB system, DBS)Ii. several common databasesOracle Oralce, thedatabase leader in the market, the programmer's girlfriends in

To view the table structure:See field names and data typesSELECT * FROM cols WHERE table_name=upper (' table_name ')To view the primary key:SELECT * from user_constraints where constraint_type= ' P 'and Table_name=upper (' table_name ')Other than