Database Administrator

The common thing about a database is that it stores data in a warehouse, and our operations on the database can be the same as what we store or take out in a warehouse. If we need to access things from a warehouse, first we need to know where the

The ORA-01940 cannot delete the user that is currently connected   When importing data in the test environment today, you need to remember the drop user operation. When you execute the drop user, the prompt is: ORA-01940: cannot drop a user that is

Test the hash index and principles of MySQL 1. hash index: (hash index) is implemented based on the hash table. Only queries that precisely match the index column can achieve the effect. For each row of data, the storage engine calculates a hash

One Linux or UNIX Machine Sets multiple DB2 systems before DB2 for Linux, UNIX, and Windows Version 8, SAP customers can only install one copy of each DB2 Version on one physical machine, the installation path is hard-coded. Although DB2 Version 8

Simplify the installation of Oracle Database11g on Oracle Linux 5 Directory 1. Introduction of Oracle-validated RPM for oracle Linux2. Install oracle-validated RPM3. Configure the Directory and set the group and permissions of the directory owner4.

(1) remote TELNET to back up data to the SHLL script of the tape drive Lgmfcm:/u01/Oracle/CIC/BACKUP] cat TAPE_BACKUP.sh:$ {OK = 0 }$ {FAIL = 1 }$ {CANCEL = 3}: $ {MM = 'date + % m '}: $ {DD = 'date + % d '}: $ {YY = 'date + % y '}: $ {DEVFILn =

Unable to open the connection to SQL Server, SQL Server After several days of login to the restructured version of the data room charging system, the login form was finally knocked out, and the code debugging was almost done, and the problem was in

NoSQL databases: data consistency, nosql Database ConsistencyNoSQL Database: Data ConsistencyRead consistency High ConsistencyAccess any node in the cluster at any time, and the data obtained is consistent; User consistency is consistent with the

Oracle provides the following explanations for ASCII and CHR functions: ASCII (x) gets the ASCII value of the character X, CHR () and ASCII () have the opposite effect. That is, the ASCII function is used to convert characters into their

Review of the history of AI into China, review of the history of AI In 1955, American scholar John McCarthy (1927-2011) first proposed the term "AI", meaning: artificial intelligence is The science and engineering of making intelligent machin ".

When big data talks about this, there are a lot of nonsense and useful words. This is far from the implementation of this step. In our previous blog or previous blog, we talked about our position to transfer data from traditional data mining to the

What is the length of the int type after mysql creates a table? Is this column the maximum width allowed to store values? Why can I set it to int (1) and save 10,100,100 0.At that time, although I knew int (1), the length of 1 does not mean that the

Recently, when sorting out content related to the test environment, students often ask the following terms: Database Name, Instance name, database domain name, Global Database Name, service name, This is a few confusing concepts for many beginners.

Install mysql on mac and mysql on mac There are two ways to install mysql under mac, one is to directly go to the http://dev.mysql.com/downloads/mysql/ to download a dmg installation package, and then one way to install. However, there is a problem

Tutorial on installing and using the extension module on PostgreSQL, postgresql extension module Installation Module Note: My runtime environments are Ubuntu 10.04 and PostgreSQL 8.4. First, install the postgresql-contrib package and restart the

MySQL encoding format. mysql modifies the encoding format. I. Problem Introduction When mysql is installed, the encoding format is configured as UTF-8. Therefore, mysql character_set_client, character_set_connection, character_set_database,

09. cyclic queue and chain queue, 09 cyclic queueI. queue and cyclic queue1. Queue(1) A queue is a linear table that only allows insertion at one end and deletion at the other end. A queue is a linear table of Fiirst In First Out (FIFO. The end that

BCP is generally stored in the BIN directory of the installed ASE or Open Client. For ASE earlier than version 12, the bcp directory is $ SYBASE/bin, and for Versions later than Version 12 (including version 12), the directory is $

The deduplication technology can provide a larger backup capacity for longer data retention, continuous verification of backup data, improve the level of data recovery services, and facilitate data disaster tolerance. Duplicate data may be in the

This article will introduce several major steps for SQL Server Profiler to analyze deadlocks. This is also to help you better manage your databases. In two or more SQL Server processes, a deadlock occurs when each process locks the resources that