Database Administrator

Database transaction isolation and lock, database transaction isolationOverview I have learned about database transaction isolation and lock. Now I want to explain my understanding. Database transaction isolation Concept Transaction: Multiple SQL

In xml, SQL statements are processed much less than numbers, and xmlsql When we need to process SQL statements in xml format, symbols such as ,> = are often used, but it is easy to cause xml format errors, this will cause the background to convert

ORACLE-008: classification statistics, oracle008 Classification Classification statistics are usually used to count the number of items or the number of items under a certain item. Simple, such as tab_test Tab_test record Id Co

A scenario of database index failure: Analysis of the Problem ideas and strategies, index analysis problems This is a problem about database index failure discovered by the company's R & D team. Our engineers analyzed and solved the problem and

About MySQL's SLEEP (N) function, mysqlsleep FunctionWe all know that you can run this statement for N seconds by executing select sleep (N) in MySQL: mysql> select sleep(1);+----------+| sleep(1) |+----------+| 0 |+----------+1 row in set (1.

02. Linear table (1) sequential storage structure, 02 linearSequential Storage StructureI. Basic concepts of linear tables1. Linear table definitionA linear table (list) is a finite sequence of zero or more data elements. All data elements are of

Oracle cold backup and oracle backup Prerequisites for cold backup:The operating system is the same. You can execute scripts from Win32 to Win64 and from Win32 to Win64.Procedure:A. view the control files, data files, and log files of the two

[Oracle] export ledba29 The backup wocould be marked as obsolete., obsolete You defined the rediscovery Manager (RMAN) retention policy to rediscovery Window of 7 days by executing the following command: RMAN> configure retention policy to recovery

Oracle deletes all objects (tables, views, triggers, stored procedures, and functions) of the current user.Zookeeper  DECLARE TYPE name_list is table of VARCHAR2 (40 ); TYPE type_list is table of VARCHAR2 (20 ); Tab_name name_list: = name_list

05. Linear table (4) chain storage structure. Static linked list, linear chainChain Storage Structure-static linked listI. Static linked list1. Static linked list Storage StructureA single-chain table is implemented through pointers, but we can also

[Incomplete recovery], [non-recovery]Incomplete recoverySet until scn Set until time | timestamp... the most commonSet until logseq <>Example of Incomplete recovery:SQL> conn scott/tigerConnected.SQL> select to_char (sysdate, 'yyyy-mm-dd hh24: mi:

[Non-critical data file loss (data file loss can be performed offline)-restore-1], key offlineNon-critical data file loss (loss of offline data files ):Run {SQL 'alter database datafile <> offline ';Restore datafile <>;Recover datafile <>;Slq 'alter

Database: Table Structure and Data Replication instance, copying instanceSolution 11.1Copy the entire table (including data without primary key index): old_table ---> new_tableCreate table new_table SELECT * FROM old_table;1.2Copy the entire table

Database Course Design recontinued, database Course DesignThe coffee sales management system adds a table bill2 to solve the problem that a user corresponds to multiple products. However, after writing the table, several redundant items are found,

Mysql JDBC interface programming and mysqlJDBC Interface ProgrammingThe relationship between the JDBC interface driver package version of mysql and the mysql version can be found on the official website. For specific examples, see the following.

SQL statements Delete primary keys, change primary keys, delete duplicate columns (Multi-column combination), and SQL multi-Column-- Alter table HistoryData drop constraint PK_HistoryDataAlter table HistoryData add constraint PK_HistoryData primary

[Oracle] Release ledba26 RMAN recovers up to log sequence 230, but not including 230., export ledba26rman Our database operates in ARCHIVELOGmode. The redo log files are Not multiplexed and one of the online redo logs is missing. The missi Ng redo

[Oracle] revoke ledba23 change the backup retention policy to retain the backups for a sma roller period o, reinstallbackups An RMAN backup job fails, displaying the following error: ORA-19809: limit exceeded for recovery files Your analysis shows

Mysql-timed call of stored procedures, mysql-stored procedures Mysql regularly calls the stored procedure to back up the table structure. Stored Procedure instance: CREATE PROCEDURE backUpSms()BEGINDECLARE tname varchar(64);set @tname = CONCAT('sms_

Sqlplus component damage recovery test, sqlplus component testSqlplus component accidentally damaged and restoredAfter executing the sqlplus/as sysdba command, there is no response, which is a bit strange...[Oracle @ lixora bin] # sqlplus/as