Oracle

Scenario: storage media is corrupted, resulting in loss of control files, the need to replace the hard drive, and to re-establish control files.(1) Modify initialization parameter control_files, change control file locationsql> ALTER SYSTEM SET

1, first to understand Oracle on the operating system to open the Shutdown Database command Start Stop database script under command line, execute with Oracle user $ Dbstart Open Database $ Dbshut Close Database But to enable the above command,

The Oracle physical structure is a collection of physical operating system files. Control file (parameter file Init.ora records the location of the control file) Binary file, the control file is specified by the parameter control_files, the format

1. When you use the Where, group BY, and having clauses in a SELECT statement, they function and execute in the following order: (1) Where is used to filter the data object specified by from (2) Group by for grouping the results of the Where (3)

When we look up the Chinese dictionary, we can quickly find the word we are looking for because the dictionary is indexed. Similarly, in order to get data efficiently, we need to index a column in a table when the volume of data is large. The role

First, let's talk about what they have in common: they are essentially exclusive locks on resources that are caused by concurrency (if the database has only one session, it's not locked). Then focus on the different points: First of all, their

A simple example of how an oracle who has not contacted Oracle for a project in the company is prepared to use the Proc implementation additions and deletions: CREATE TABLE T1 ( SID number NOT NULL primary key, Sname VARCHAR2 (10) ) Tablespace

In order to do this experiment I first create a user, user name: 111 Password: 111 Sql> create user identified by 111; User created. Sql> Grant connect to 111; Grant succeeded. Test on the client link $ sqlplus 111/111 Sql> select Sysdate

Colleagues in the test library on a table add fields, prompt ORA-00054, resources busy. The lock on the Table object should not be released. Use the following SQL to view the locking of related objects in the system: /* formatted on 2012/2/13 14:2

--View the low-efficiency SQL method as follows Select A.sql_text, A.executions, A.disk_reads, A.buffer_gets, Round ((a.buffer_gets-a.disk_reads)/a.disk_reads,2) Hit_radio, Round (a.disk_reads/a.executions,2) Read_per_run From V$sqlarea A

/* Before creating a tablespace under the server directory/optoracle/oradata/etld, manually build the Etld directory and use root to give the Etld directory the appropriate permissions, such as 777 */ --Create a table space Create Tablespace Tbs_

Application Scenario: Large data --1), create a partition table CREATE Table A (Statis_date varchar2 (8), ID number, Name VARCHAR2 (50), Salary number ) Partition by list (statis_date) (Partition day_20121130 values (' 20121130 '),

1. Index Information View: Select * from User_ind_columns; Select * from User_indexes; 2, monitor the index of the Open: ALTER INDEX index_name monitoring USAGE; 3. See if the index you created is valid: Execute the query SQL statement first,

Parallel DML operations should be noted for 2 points: 1), display in session execution: Alter sessions enable parallel DML; 2, for Delete, Update, merge operation, only the object is the partition table, Oracle will enable parallel operation; 3),

Parameter files are settings that are used to configure the database. such as the location of the control file (control_files), the size of the data block (db_block_size), buffer cache size (db_cache_size), and other information 1. Oracle parameter

Application scenario: Easy and quick recovery of table data; Flash back Table 1. Set the properties of a table ALTER TABLE AAA enable row movement; 2, restore the table data to 2 minutes ago Flashback table AAA to timestamp sysdate-(1/24/3600) *

For SQL optimization, from the actual work experience, summed up as follows: 1, where filter section, the equation left without any calculation and nesting functions, to find an equivalent replacement, on the right side of the equation to make

To prevent remote SSH logons for Oracle users, the passwd file was modified with VIPW today and added at the end of the Oracle User::/sbin/nologin Test discovery does prevent users from SSH logons, but the following errors are reported after you

1. Stop the database using Sql*plus[Oracle@oracletest oracle]$ Sqlplus/nologSql> Connect/as SYSDBAsql> shutdown [Immediate]Sql> exit 2. Stop Listener[Oracle@oracletest oracle]$ Lsnrctl Stop 3. Stop HTTP Service[root@oracletest/root]# Service httpd

MySQL: How to transfer millions data from Oracle to MySQLhttp://blog.csdn.net/hwhua1986/article/details/53257427Oracle to MySQL migration steps and a variety of considerationsHttp://www.2cto.com/database/201305/210248.htmlMySQL vs. Oracle diff data