Database Administrator

SQL> select * from t_char;--------------------A_ BAcbA % BA' BA/BA \ B%_ASQL> select * from t_char where a like 'A _ B ';--------------------A_ BAcbA % BA' BA/BA \ bSQL> select * from t_char where a like 'a \ _ B 'escape' \ ';--------------------A_

1. How to check whether a parameter is dynamic or static We can find the parameter in v $ parameter. Column value format a40; Column name format a20;Select name, VALUE, ISSES_MODIFIABLE, ISSYS _ modifiable from v $ SYSTEM_PARAMETER; Here, the

The syntax of the SELECT... for update statement is as follows:SELECT... for update [OF column_list] [WAIT n | NOWAIT] [skip locked];Where:The OF clause is used to specify the columns to be updated, that is, to lock specific columns on the row.The

The distinct keyword filters out redundant duplicate records and retains only one record. However, it is often used to return the number of records that do not record duplication, rather than returning all values that do not record duplication. The

The portable tablespace can now be migrated across platforms, making data publishing faster and easier. In addition, external table downloads make data transfer tasks easier and faster through conversion. How do you migrate data from one database to

We recommend a very good CentOS 4.4 installation of the Oracle 10g system, which is of great learning value. Here I will mainly explain the application of installing the oracle 10g system, including introduction to the knowledge of installing the

Auto restart of Oracle Database and DDS software in Linux single-instance Environment 1. Modify/etc/oratab# Vi/etc/oratabOradb:/opt/ora10/product/10.2.0.1: Y (changed from N to Y) 2. Modify/etc/selinux/config# Vi/etc/selinux/configSELINUX = disabled

An Oracle archive log is often full, as the file space occupied by/oraarchive is 100%. Everyone must complain about why Oracle does not have an archive maintenance tool. Many people delete the file directly. Wrong, Oracle has, it is intelligent to

Run yum to check whether mysql has been installed on Fedora 13 and you do not want to uninstall it and reinstall it. Typing mysql directly does not respond. For details, refer to here. I don't know how to deal with it. Now let's look back.Step 1: #

This feature is required for projects. When I use navicat to set the date type to timestamp, I will find that IDE has one more option: View the SQL statements automatically generated by IDE: Write 'lastupdate' timestamp not null default '2017-00

Class. forName ("Oracle. jdbc. driver. OracleDriver"); //. newInstance ();String url = "jdbc: oracle: thin: @ FIG: 1521: yyyy ";// Mydb is the SID of the database, and 10.0.1.1 is the IP address of the database server.String user = "sys as sysdba

Hadoop version: Hadoop 2.2.0.2.0.6.0-0009 Well, We can do this by building Secondary Namenode, Checkpoint node or Backup node. Example: Assuming you have a Secondary Namenode. 1. Check secondary namenode checkpoint status: Dfs. namenode. secondary.

Source: http://blog.csdn.net/dba_huangzj/article/details/31374037 reproduced Please reference I have seen a discussion on in/exists in the forum. I am too lazy to find the original post. Here I will introduce the recent study summary: Not in and

I often see an hint/* + OPAQUE_TRANSFORM */In the AWR Report, which is inexplicable. Why? If you see this hint in AWR of database B, the reason is that other databases ACCESS database B through DB link, and access using insert into table_name select

Dictionary and dynamic view Oracle dictionary and Dynamic View The oracle service displays all the system statistics in the v $ sysstat view. It also uses many views to display oracle performance and problematic snapshot information. You can query

In such a scenario, after multiple agent Systems (each with their own database) perform their own operations, complex operations will be triggered for the stored procedures of their respective databases, after each operation is complete, you need to

Due to Oracle authorization problems, Maven3 does not provide Oracle JDBC driver. To Apply Oracle JDBC driver to Maven projects, you must manually add the driver to the local repository. 1. Obtain the Oracle JDBC Driver 1. Download the appropriate

What is the serial number in the Oracle database? Sometimes, when we add an index field to a new table (without any business functions), to ensure that the field value is unique during each data addition operation, you can create a sequence

Mysql5.6.15 forget the root password of the database:[Root @ oraserver139 ~] # Mysql-uroot-pEnter password:ERROR 1045 (28000): Access denied for user 'root' @ 'localhost' (using password: NO)View the currently installed mysql version:Root @

Set the database to start several dispatcher (start three dispatcher) SQL> alter system set dispatchers = '(protocol = tcp) (dispatchers = 3 )' Set the maximum number of dispatcher instances that can be started in the database at the same time