Database Administrator

Detailed analysis of InnoDB indexes in MySQL Abstract: This article introduces the InnoDB Index-related knowledge of MySQL, from various trees to the indexing principle to the details of storage. InnoDB is the default storage engine of MySQL (MyISAM

MySQL 5.5.40 implements One-Master-multiple-slave One-Master muil-slave We know that the overhead of MySQL Reading and Writing Performance is quite different. Generally, the server is under 20% write pressure, and the other 80% pressure comes from

Oracle BUG caused instance downtime: ORA-07445 Symptom:The customer's database (RAC environment: 11.1.0.6) encountered abnormal instance downtime, accompanied by a ORA-07445 error:Sun Jun 23 01:00:06 2013Exception [type: SIGSEGV, Address not mapped

Database instance cannot be started after ORA-39700 Oracle 10g upgrade Upgrade Oracle Database 10.2.0.1 to 10.2.0.5 todayAn error occurred while starting the database:ORA-01092: The ORACLE instance terminated. Disconnection forced instance is

Oracle ORA-27121 troubleshooting ORA-27121: unable to determine size of shared memory segmentCause: shmctl () call failedAction: check permissions on segment, contact Oracle support Cause: The oracle database is migrated through the cold copy

Oracle TRUNC () function usage, oracletrunc TRUNC () function usage in Oracle 1. Processing date TRUNC (date [, fmt]): truncates a date based on the fmt Format. Select trunc (SYSDATE, 'D') from dual; -- select trunc (SYSDATE, 'mm') from dual on the

Set IP address access restrictions for oracle11gip For data security considerations, make some restrictions on the IP address of the oracle database. Only a fixed IP address can be accessed. Modify the $ JAVA_HOME/NETWORK/ADMIN/sqlnet. ora File Add

SQLite creates a table and adds data. sqlite creates data. -(Void) viewDidLoad {[super viewDidLoad]; // create a table [self creatTable]; // insert data [self insertTable];} // --------------------- create a table ------------------- (void)

Oracle Performance Analysis 12: Object statistics and oracle statistics Object statistics describe how data is stored in the database. The query optimizer uses these statistics to make the correct decision. Oracle has three types of object

Oracle ceil rounded up and ceil rounded upSelect ceil (3.05/0.5), 3.05/0.5 from dual;Ceil (3.05/0.5) = 73.05/0.5 = 6.1Ceil (3.55/0.5) = 83.55/0.5 = 7.1Oracle integer Functions Ceil (x) rounded upFloor (x) rounded downRound (x, n) is an integer when

Query the permissions or roles of a user in oracle db. The simplest method is to log on to the database with the user and execute the following statement: Select * from session_privsselect * from session_roles In oracle, how does one find

Oracle ORA-06550, oracleora-06550DeclareCnt integer;BeginSelect count (0)Into cntFrom user_all_tablesWhere table_name = upper ('dps _ BIZTYPES_MANAGE ');If cnt = 0 thenExecute immediate 'create table DPS_BIZTYPES_MANAGE(Id Integer not null,BIZTYPE

Kettle uses javascript steps and fireToDB functions to implement custom database queries. kettlefiretodb Kettle uses javascript steps and fireToDB functions to implement custom database queries   Assume that you need to perform non-traditional

MongoDB's full-database backup is also restored from the original single-table collection backup, mongodb single-Table backup MongoDB full-database backup and original single table collection backup and Restoration Cd D: \ MongoDB \ bin   1

Mysql SQL Statement Review 1. Mysql SQL Statement Review Search the list without the same value and add the DISTINCT keyword. Select distinct vend_id FROM products; You can use the LIMIT clause to LIMIT the number of returned results. SELECT

Preliminary specifications for MySQL Database Design: V1.0 and mysqlv1.0   Database Design specifications:1. Table design specifications 1.1 Table Design A) The table name and column name must be annotated. B) The name should contain meaningful

Oracle Installation Error: environment does not meet requirements solution, oracle times In the past, I often encountered this problem when installing Oracle, and I didn't care too much about it. I modified the cvu_prereq.xml file under the client \

Oracle exports the table as a txt file, oracletxt This article lists several methods to export data from an oracle table to a txt file. Currently, only three methods are listed. If better methods are found later, they will be added continuously.   1.

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