Database Administrator

Oracle Database transfer from server A to server B Sometimes we encounter such a situation where the existing database needs to be transferred from one machine to another. Generally, we use export and import. However, if the database contains a

How to obtain the variable value bound to an Oracle SQL statement When diagnosing SQL Performance problems, we sometimes need to obtain the actual value of the variable it binds, and then bring the actual value into the SQL statement, use the

Relationship between the server parameter file (spfile) in the Oracle 11g parameter file and instance startup When the database starts, it needs to read the parameter file to allocate the memory area and locate the location of the control file. The

Notes for handling ORA-4065 errors When receiving channel feedback, a user prompts when performing software operations'ORA-4065 not executed, stored procedure Zl_XXXX_Finish changed or deleted', The user tries to re-compile the process and can use

Summary of Oracle rebuild table (rename) Considerations I. OverviewSome time ago, a DBA friend failed to run the business on the morning of the next day after he finished the rename operation and encountered the restriction and error that the data

Pay attention to designing system updates and patches.We usually develop a system that must be upgraded frequently. Upgrading means modifying the code or data structure. Of course, you should try to modify the data structure as little as possible in

Check the Statement of the Oracle transaction and the statement of the oracle transaction. SQL> SELECT KTUXEUSN, KTUXESLT, KTUXESQN, /* Transaction ID */ 2 KTUXESTA Status, KTUXECFL Flags ,KTUXESIZ 3 FROM x$ktuxe 4 WHERE

Database optimization tips and database optimization tipsDatabase TIPS ::1. When creating a table for record or data analysis: Use Id as the primary key, 1, 2, 3... indicates the number of messages. The user account id is used as a foreign key. A

Atitit. view the nature and principles of pre-compiled SQL question marks and view native SQL statements and atititsql   Atitit. view the nature and principles of pre-compiled SQL question marks and view native SQL statements   1. Pre-compilation

Hive SQL optimization: distribute by, sort by, and hivedistributeHiveSQL has been optimized recently, The following is an SQL statement that sorts records from the first row of each group after grouping.

DDL (Data Definition definitions ages) and ddldefinition I haven't written any SQL statement for a long time. Let's review it. DDL defines different data segments, databases, tables, columns, indexes, and other database objects. Common DDL

Cocould not find gem 'sqlite3 (> = 0) 'in any of the gem sources listed in you r Gemfile, sqlite3gemfileSolution: sudo gem install sqlite3-rubyERROR: cocould not find a valid gem 'rdiscount' (> = 0) in any repository This problem happened to me for

Access denied for user: 'root @ localhost' (Using password: YES ), After mysql is successfully installed in centos First use of root logon: Access denied for user: 'root @ localhost' (Using password: YES) The reason is that the root password in

Set the maximum number of mysql connections in CentOS to 1040 too persistent connection and centosmysql.When the maximum number of connections is small, the error "1040 too connection" may occur.You can modify the configuration file to modify the

MySQL Regular Expression search, mysql Regular Expression The products table is as follows: 1. Basic Character matching The difference between regular expression and LIKE is that regular expression searches for the entire column, As long as prod_

In the previous two blogs, we analyzed the functions and databases of the system. Today, we started to practice and further analyze the system. Our program design consists of two steps: interface design and code design. Today, let's take a look at

Mongodb Install mongodb I think mannual install is a little more reliable: http://docs.mongodb.org/manual/tutorial/install-mongodb-on-os-x/ Start mongodb $ Mongod Connect to mogodb $ Mongo Mongo> use monk-app Mongo> db. products. insert ({"name":

There are two types of Standby databases:1, Physical standby databaseBlock-for-block basisThe physically identical with the primary databaseUser recovery technology2. Logical standby databaseShares the same schema definition withe the primary

Practical Functions DECODE Syntax: DECODE (value, if1, then1, if2, then2, if3, then3,... else) Value represents any column of any type in a table or any result obtained through computation. When each value is tested, if the value is if1, the result

The differences between mysql semi-synchronous replication and asynchronous replication are shown in the preceding architecture diagram: when mysql asynchronous replication occurs, after the Mysql Master Server transfers its Binary Log through the