Database Administrator

1. Complete table creation syntaxCreate table [schema.] table(Column datatype [, column datatype]… )[TABLESPACE tablespace][PCTFREE integer][PCTUSED integer][INITRANS integer][MAXTRANS integer][STORAGE storage-clause][LOGGING | NOLOGGING][CACHE |

New Features of Oracle 12C Temporary UNDO can reduce the amount of data stored in the undo tablespace and the generation of redo logs [Oracle @ db12c ~] $ Sqlplus/as sysdba SQL * Plus: Release 12.1.0.1.0 Production on Mon Apr 28 14:18:21

Overview of dynamic sampling Dynamic Sampling was initially proposed in Oracle 9i R2, where segments (tables, indexes, partitions) are not analyzed, A technique invented to enable the CBO optimizer to obtain sufficient information to ensure a

I. Data Backup Methods MySQL parameter description: MySQL management-data backup and recovery 1. Physical backup 1.1 Cold Standby cp tar and so on 1.2 Hot Standby mysqlhotcopy can only back up tables whose storage engine is myisam and rely on

Scenario: Some colleagues need to synchronize data from the database to the new environment. However, they find that the execution of the count Statement on the master database is different from the execution of the count Statement on the slave

Environment] AIX (5300-08), Oracle10g (10.2.0.1.0-64bit) [Goal] Due to the large data volume in the production environment, we want to speed up rman backup. [Method] Start block tracking Operation] SQL> alter database enable block changetracking

[Scenario overview] The parameter file of the server is lost in the production environment, and rman has enabled Automatic Backup Settings. [Operation process description] ---- Start rman $ Rman target/ ---- Check rman settings RMAN> show all; ----

1. MyISAM does not support transactions. InnoDB is a storage engine for transaction types. When transaction support is required for our tables, MyISAM cannot be selected. 2. MyISAM only supports table-level locks. BDB supports page-level locks and

Check whether the user has the Flashback permissionSelect * from session_privs where privilege like 'flashback % '; Grant user Flashback permissionGrant flashback any table to test; Restore the deleted data.Alter database add supplemental log

The previous article discussed the new features of adding columns to a large table in 11g, Before 11g is mentioned, you can add rows and columns (with default values) by means of online redefinition of tables ). Online permission redefinition

Compile a doscommand script to generate a batch command file, and then add a scheduled task to the host server. Backup method: Create a bak folder in the root directory of any disk, create week0.dmp In the bak folder, copy the following DOS command

Oracle cursors are divided into explicit and implicit games. Explicit cursors are defined and operated by users and are used to process query results that return multiple rows of SELECT queries; implicit cursor is a SELECT query that is

Oracle PLS-00231 error analysis, this error is generally caused by the function access permissions, declared as a common function in the header is fully pass, if declared in the package body will die from the function will cause errors. Create or

In the morning, the boss said that the temporary tablespace is empty. Let me see it. I see the ORA-25153, it must be because the logical name of the temporary tablespace is still there, but the temporary file cannot be found. Solution: 1. query the

Java database connection steps 1. Open the connection 2. Create a statement set: a normal statement set and a predefined statement set Statement stat = conn. createStatement (); PreparedStatement priceUpdateStmt = Conn. prepareStatement ("SQL

Restoration of Oracle online redo log loss (1) Loss of members of the inactive online redo log file If the database has not been closed and the member of the active redo log group or the current redo log group is lost, use alter database checkpoint

Verify the validity of RMAN backup 1. restore preview commandThis command is used to check which backup set is used for restoration to perform specific restoration.Restore database preview;2. Use the restore command of the validate and check

Oracle's nologging attribute is very vulnerable to misuse. In our previous article, we discussed the impact of append + nologging on Redo logs. From the conclusion of this article: If we use append and nologging, we can indeed reduce the generation

Oracle redo log is used to record operation entries for database data recovery. To improve efficiency, we recommend that you set up three redo logs for oracle. This article will parse the status of the redo log group and switch between multiple

I. Features of enabling flashback database:1. Make sure that the database is in archive mode. If it is not in archive mode, convert the database to archive mode.SQL> archive log list;Database Log mode archiving ModeEnable automatic archivingArchive