Oracle

  1). tablespace A table space is the logical division of a database. Each database has at least one table space (called a system table space ). To facilitate management and improve operation efficiency, you can use an additional table space to

SQL statements are divided into three types: DML, DDL, and DCL. the DML and DDL operations have been completed before, and the DCl operations are poor now. DCL mainly indicates the control statements of the database, the operation permission is

Database Backup is one of the most important tasks in the whole project operation. I. Data Export and Import Data export and import are for a user's backup operations, which can be completed as follows: 1. Data Export Create a folder

The database design paradigm is a very important concept, but this importance is only suitable for reference. With the database design paradigm, data tables can be better stored, because a reasonable design will certainly have performance problems

I. Hardware requirements 1. Memory & swap Minimum: 1 GB of RAMRecommended: 2 GB of Ram or more Check memory # Grep memtotal/proc/meminfo # grep swaptotal/proc/meminfo 2. Hard Disk Since centos is installed almost 4 ~ 5 GB, plus Oracle

Source: http://www.cnblogs.com/zjrstar/archive/2006/08/31/491090.html For rownum, it is the number of the row returned from the query that is sequentially allocated by the Oracle system. The first row is allocated 1, and the second row is 2, this

1. How Does Oracle store text? Differences between char and varchar2 • Char fixed-length string, varchar2 variable-length string. • Char (n) fixed-length string, n Bytes, N value range:1 ~ 2000 bytes. • Varchar2 (n) variable-length string.

1.System Variable Functions (1)Sysdate This function returns the current date and time. The current date and time of the Oracle server are returned. Select sysdate from dual; insert into purchase values ('smallwidget ', 'sh', sysdate, 10)

Oracle's online redefinition Table Function In a high-availability system, changing the definition of a table is a tough issue, especially for a 7 × 24 system. The basic syntax provided by Oracle can basically meet general modification

-- Authorization Grant   Create   Table , Create   View   To Scott; Grant   Select   On Dept To TT; -- Grant tt the dept permission -- Delete permission Revoke   Select   On Dept

I. View Among all the SQL syntaxes I have learned before, query operations are the most troublesome.ProgramIf developers waste a lot of effort on writing queries, it will certainly affectCodeTherefore, a good Database Designer not only designs

From: http://www.cnblogs.com/ruanbl/archive/2008/02/29/1086398.html Extract extracts and returns the value of a specified datetime field from a datetime or interval value expression.The field you are extracting must be a field

To_date format (take time: 13:45:25 as an example)Year:YY two digits two-year display value: 07YYY three digits: 007Yyyy four digits four-digit year display value: 2007Month:Mm Number: 11Mon abbreviated Character Set indicates the displayed value:

1. Create a tablespace Create tablespace ccpbs datafile '/home/Oracle/bossdata/ora_data/ccpbs_index01.dbf' size 100 m reuse default storage (initial 5000 K next 5000 K pctincrease 20 ); 2. Create user Create user osuser identified by osuser; //

1. log on to the database using an oracle user [Oracle @ wuzj ~] $ Sqlplus/nolog SQL * Plus: Release 10.2.0.1.0-production on Thu Feb 26 12:06:29 2009 Copyright (c) 1982,200 5, Oracle. All rights reserved. SQL> Conn/As sysdbaConnected. //

Create smallfile tablespace "jxkh" datafile 'f: \ oracle \ product \ 10.2.0 \ oradata \ temp \ jxkh 'size 100 m autoextend on next 5 k maxsize unlimited logging extent management local segment space management auto; Create user jxkh identified by

There is no need to worry about Oracle's massive data volume.If you want to transfer a large amount of data in Oracle (more than 80 Mb) to another user and another tablespace. You can use the following method to quickly transfer data. I. How to

1. Search for all indexes of a table (including index names, types, and columns ): Select T. *, I. index_type from user_ind_columns T, user_indexes I where T. index_name = I. index_name and T. table_name = I. table_name and T. table_name = table to

This knowledge point is only applicable to Oracle 9i and later versions. To view table data changes, use the SQL statement: Select * From user_tab_modifications; The fields in the user_tab_modifications table are as follows:Modify, delete, and add

(From http://duqiangcise.javaeye.com/blog/563296) 1. view the system permissions of the current user Select * From session_privs;2. view all roles in the databaseSelec * From dba_roles;3. view the maximum number of roles supported by the databaseSQL>