Database Administrator

1: view memory: grep MemTotal/proc/meminfo View swap: grep SwapTotal/proc/meminfo 2: Check the RPM package. Red Hat Enterprise Linux

Installing Oracle 10 Gb in CentOS 4.6 may cause the following common errors: The preceding error indicates that the Display variable of the X11 Window Server is incorrectly configured. Solution: open a terminal as root and enter "# xhost +" and "#

Oracle locks can be divided into several types: DML lock (data lock), DDL lock (dictionary lock) and internal lock/latch.DML lock can be divided into row lock and table lock. Row lock in select .. for update/insert/update/delete is automatically

(1) When the header file mysql. h cannot be found,Cd/usr/include/mysql/Cp */usr/include/ (2) When undefined reference to 'mysql _ init' occurs,It is best to use # gcc-o test. c 'mysql _ config -- cflags -- libs'Other compilation commands: # gcc-o

After Oracle is installed, a database is created and no listening service is found. You can solve this problem by using the following method. Run Net Configuration Assistant and select Add Listener Configuration Configuration items are simple.

Environment Description: Operating System: CentOS 5x86Database: Oracle 10.2.0.1 non-RAC EnvironmentASM instance name: + ASM Refer to metalink node: 311350.1 1. Check the process of the ASM instance. Www.bkjia.com @ oracle [/home/oracle]> ps-ef |

1. select d. id, d. outer_code from dict_depts_source d order by outer_code (view duplicate data) 2. select d. id, d. outer_code, row_number () over (partition by outer_code order by outer_code) row_flag from dict_depts_source d (identifies

Problem: The input floating point number and decimal place, Input output ---------------- 0.123 0.12 .. 123 0.12 . 1 0.10 .. 199 0.20 123.199 123.1990 Solution: Create table test_t ( Col_1 number (3, 2 ), Col_2 number (7, 4) );

1. The Oracle Database client was installed. The method for connecting to the oracle database on the remote server is as follows: 2. Later, the system was reinstalled and oracle was installed. The method for connecting to the oracle database on the

1. Install and start mySQL: 1. If mySQL already exists in CentOS /Etc/rc. d/init. d/./mysqld start (start mySQL and run mySQL-root) Edit the rc. local file # vi/etc/rc. d/rc. local Add the following startup command /Etc/rc. d/init. d/mysqld

I read something about the Oracle database because of some database problems. For records in a table in an Oracle database, how can we delete repeated values. I will keep a record of my practices for future reference. The data I use is oracle.

Due to accidental deletion of Oracle table data, the data may be very important. How to quickly restore the data so that the supervisor does not discover it can write a stored procedure to restore the data at the previous time of data

[DDL] Create table Alter table Drop table delete table Truncate table delete all rows in the table Create index Drop index Delete index When a DDL statement is executed, Oracle submits the current transaction before and after each statement.

In Oracle 10 Gb, you need to set workarea_size_policy to AUTO, and set the pga_aggregate_target parameter to implement memory management of PGA. SQL> show parameter pga NAMETYPE VALUE ------------------------------------------------------------

During work, we often observe the space release and Application Performance Improvement brought about by index reconstruction. Space release is easy to understand and measure. How much will index reconstruction affect the performance of applications?

Oracle Introduction Oracle is the first word for English translation of oracle (Oracle bone inscriptions) Unearthed from Yin. Oracle is the world's largest supplier of information management software and services. It was founded in 1977 and is

I believe everyone is very familiar with the index structure. It is composed of roots, branches, and leaves. Of course, this refers to the common B + tree indexes. We still use the test table in Oracle collection table and column statistics (see.

In Oracle, columns in the table below the sys user cannot be dropped. If drop is performed, an error is returned: SQL> desc test Name Null? Type ----------------------------------------------------------------------------- Id notnull number

UNDO function:1. rollback2. Construct CR blocks to provide read consistency3. rollback: When the instance is restored Undo table empty area status:1. free available rollback segments2. active indicates that there are active uncommitted transaction

After Fedora 19, Fedora replaces mysql with mariadb. Although these two things are the same, I still like mysql, and I don't know why. In Fedora 20 (64bit), I only installed mariadb once, no solution can be found on the Internet. (If anyone knows,