Oracle

Dual is a virtual table used to form the select syntax rule. oracle ensures that there will always be only one record in dual. We can use it to do a lot of things, as shown below: 1. To view the current user, you can execute the following statement

I often read some articles to solve many of my own problems, but I am always embarrassed to read the articles that others read. After all, I learned others' experience and improved myself, but I didn't share it with others. I also want to write some

Database usage: oracle tablespace operations1. view the space used by the database table select tablespace_name, sum (bytes)/1024/1024 from dba_data_files group by tablespace_name;2. view the remaining tablespace in the database SELECT

Suppose there is a table TEMPSQL> SELECT * from temp; id info ---------- limit 1 aaa 2 bbb 3 ccc SQL> delete from temp id = 1; 1 row deleted SQL> COMMIT; commit complete SQL> SELECT * from temp; id info ---------- restore 2 bbb 3 ccc restore Data

Oracle-After configuring the local database to configure the local database, you can import the server data to the local database. The procedure is as follows:1. Enter the PL/SQL Developer login page, enter the Administrator's username and password (

During stress tests on the oracle database on 136, we found that the physical space occupied by the database data files was more than 20 GB, however, after we clear the data of each table (truncate drops each log table), we find that the actual data

Tables store information about associated databases. Only Oracle databases can read and write these tables. Most users cannot access these tables because most of the data is stored in encrypted format. The following query returns all objects in USER

Oracle implementation Stored Procedure return query result set method -- Implementation Stored Procedure return query result set method, the following code from the network finishing

On the Linux platform, Oracle Installation reports an error. Check if the DISPLAY variable is set. Solution: Install Oracle 11.2.0.3 on Oracle Linux 6.1. When running runInstaller, an error is reported.Details: [root @ dave mnt] # xhost + access

The oracle Database allocates table space, creates users, and assigns user permissions. Operation 1. creates a temporary tablespace./* Create temporary tablespace */create temporary tablespace student_temp tempfile 'd: \ oracle \ product \ 10.2.0 \

Oracle simple query statement 1. select * from emp where deptno = 30; 2. select all employees in department 30. list the names, numbers, and department numbers of all clerks. select ename, empno, deptno from emp WHERE job = 'cler'; 3. select * from

Programmers often need to connect to the database to talk about the oracle database client and server Character Set consistency problem, which can solve Chinese garbled characters, other character garbled problems mainly refer to in sqlplus, I do

[SQL] create table tablea (id int, ip varchar (15), apps varchar (10) insert into tablea select 23, '2017. 0.0.1 ', 'aaa' go www.2cto.com declare @ Variable1 varchar (15), @ Variable2 varchar (10) select @ Variable1 = ip, @ Variable2 = apps from

Implemented through Oracle database Triggers. For example, TEST is the TEST account and the bound IP address is 10.142.244.30. Create or replace trigger sys. trg_work_logAFTER LOGON DATABASEDeclareV_program_name varchar2 (200 );V_username varchar2 (1

Oracle instant client has recently been used to reinstall the operating system. It uses the Windows 7 x64 version and is not prepared to install Oracle. So we can see the Instant Client on the official website. Xing rushed to download a 64-bit

TNS: protocol adapter Error Problem encountered today ORA-12560: TNS: protocol adapter Error Problem, after some effort the problem has been resolved, share with everyone. There are three reasons for the problem that caused the ORA-12560: TNS:

Solution environment for ora-01092 oracle instance terminated:Solaris10 64bit, oracle10gR2 64bitOperation:Mainly for database software upgrade, from 10.2.0.1 to 10.2.0.5After the software upgrade is completed, log on with DBA permission through

The SQL statement table content displayed by a group: create table TEST2 (ID NUMBER, NAME VARCHAR2 (20); insert into TEST2 (ID, NAME) values (1, 'stefanie '); insert into TEST2 (ID, NAME) values (1, 'Google '); insert into TEST2 (ID, NAME) values (1,

ORACLE row-to-column writing/* drop table foo; * // ** CREATE a demo TABLE **/create table foo (bbbid number (2 ), -- primary key depid number (2), -- unit NUMBER AAC006 VARCHAR2 (1) -- Gender 1 male 2 female 0 unknown CONSTRAINT CK_AAC006 CHECK

Oracle Tablespace and data file management [html] Database model Database tablespace Datafile Segment Extent Oracle Block OS block create Tablespace SQL> create tablespace user_data 2 datafile 'd: \ userdata \ userdata1.dbf 'size 100 m 3; The