Database Administrator

After installing Oralce, I want to connect to it. The result is that I cannot connect to the client through PL/SQL. The prompt is TNS: The Listener cannot identify the connection currently.Solution:1. view the local/$/Oracle/oracle/network/admin/Vi

MySQL Character Set 1. display character setsMysqladmin-uroot-proot variables | grep character | Character_set_client | latin1 || Character_set_connection | latin1 || Character_set_database | latin1 || Character_set_results | latin1 || Character_set_

1. GOTO, mainly used for jump, but will disrupt our program logic. It is generally not used. It can implement the RETURN and EXIT functions. 2. RETURN: RETURN to the end of the program and end the program. 3. EXIT, mainly used to EXIT the current

Package test. Oracle;Import java. SQL. *; // Add ojdbc6_g.jar to the project Public class OJ {Public static void main (String args []) {String url = "jdbc: oracle: thin :@ localhost: 1521: orcl11 ";Try {Class. forName ("oracle. jdbc. driver.

In the MySQL environment, the system for user authentication and authorization management is flexible and powerful. It not only manages what operations can be performed, but also controls the hosts from which users can connect to the server. This

To control permissions in a project, you must use the Organization class to control the data that can be accessed,For example, A person in organization A can view the personnel data of its subordinate organization, or has the right to view the

Ubuntu version: Uname-r Linux localserver 2.6.32-24-server # 43-Ubuntu SMP Thu Sep 16 16:05:42 UTC 2010 x86_64 GNU/Linux To install xe on a 64-bit system, you must first install a 32-bit Library: Sudo apt-get install libc6-i386 The next step is to

// Add the values of a column in the current row to the values of the column in the previous row, that is, the sum of the total values:With t (Select 1 val from dual union allSelect 3 from dual union allSelect 5 from dual union allSelect 7 from dual

// During the stored procedure, we often copy the field data queried from a table to a write variable,// Call the function dbms_output.put_line () in the package to print it out;// The following is an instance:Procedure show_employee (empno_in emp.

// ProblemTable TEST:ID name consumption date retirement sign (1-on-duty, 2-retired)004 Zhang San 20 2010-05-11 1007 Li Si 50 2010-06-23 1002 Wang Wu 10 2010-06-23 2004 zhangsan 100 2010-07-20 2// Group by retirement sign. The consumption count and

Replication: Copies executed statements or datasets from the master server to one or more slave servers to synchronize databases between multiple database servers. MySQL's built-in replication capability is the foundation for building large,

Recently, I was working on an Oracle database system under RHEL 5 to store the recording data of the cluster. The database driver is odbc, here is a simple record of how odbc is installed and configured. 1. Install ODBC Download

Sqlplus system/system @ orcl -- connect SQL> ed a -- create SQL textSQL> get a -- load a. SQL into the cacheSQL>/ Create temporary tablespace sa_temp -- temporary tablespaceTempfile 'e: \ dbf \ sa_temp.dbf'Size 10 mAutoextend on; Create tablespace

Generally, if you want to design a small database (with less code), but want to meet the performance requirements of massive data and access, the most effective method is to select one or more excellent Core algorithms as the engine for main

Preface: This is my first time in contact with Linux, CentOS, and MySQL. After five days, I finally succeeded in the MySQL-Cluster architecture based on CentOS 5.0. I will share my experiences with you. If you find any errors and negligence, Please

Although the Oracle system has already provided several techniques for tuning system performance, if the database design itself is problematic, especially in terms of structure, what can you do if you have the power to do? Therefore, it is

DECLAREUserid WEB_SITE.USERID % TYPE;Id WEB_SITE.ID % TYPE;CURSOR site IS select id, userid from web_site;BeginOPEN site;LOOPFetch site into id, userid;Exit when site % NOTFOUND; Insert into web_model (id, userId, siteId, name, type,

Modify MySQL running parameters and/etc/my. the cnf file adjusts the mysql running parameters and takes effect after MySQL is restarted. After MySQL 4, some internal variables can be set during MySQL running, but the restart of mysql becomes invalid.

1. Instructions Oracle Data is placed in the table, and the table segment (segment) is composed of extents, and extents is composed of Blocks. Each block can store multiple rows. OracleSGA is composed of a DB buffer cache, which consists of default,

The parameter file of Oracle RAC is different from the parameter file of a single instance. Therefore, when modifying the parameter file, pay attention to it. First, set the archive path: SQL> alter system set log_archive_dest =