Database Administrator

To some extent, any software that we take advantage of will add to our learning and life. This blog will talk about how I feel when using Power Designer.   *************************　PowerDesignerCommon

27. Which two statements are true regarding tables? (Choose two .)A. A table name can be of any length.B. A table can have any number of columns.C. A column that has a DEFAULT value cannot store null values.D. A table and a view can have the same

Granularity is one of the most important aspects of data warehouse design. Granularity refers to the level at which the data stored in the data unit of the Data Warehouse is refined or comprehensive. The higher the level of refinement, the smaller

By qx. zhongHangzhou 29 Jun 2014Development EnvironmentOS: Win8.1 x64JDK: 1.8 SEDB: MySQL 5.5 Lib: mysql-connector-java.jar1. Special correspondence between MySQL database data types and JDKThe following table lists only a few special value type

The DECODE function is one of the powerful functions of oracle pl/SQL. Currently, only oracle SQL provides this function, and other database vendors do not yet implement this function. What is the purpose of DECODE? First, let's construct an example.

Preface: Oracle is a typical C/S structure. The server provides oracle service instances, which are mainly used for database management, object management and storage, and data Storage, query, database resource monitoring, monitoring, and other

The field "automatic number" type changed in Access cannot be changed back! (Resolved) When the auto-increment field in access is changed to a value and then to an auto-increment field, the following message is displayed: After data is entered in

To ensure database integrity and consistency, You need to execute multiple SQL statements to achieve the desired purpose. In a one-to-many database relationship, such as the relationship between the card number category and card number. If you want

Use the exact numeric data type of integer data.BigintInteger Data from-2 ^ 63 (-9223372036854775808) to 2 ^ 63-1 (9223372036854775807) (All numbers ). The storage size is 8 bytes.IntInteger Data from-2 ^ 31 (-2,147,483,648) to 2 ^ 31-1 (2,147,483,64

Download the patch package p8202632_10205_linux-x86-64.zip from the cluster environment 10.2.0.5 or above this day. decompress the package and install the package. An error is reported during the process: I/O ERROR cannt reading or opening file

Create table student (id varchar2 (5) primary key, name varchar2 (20) not null, sex char (2) check (sex = 'male' or sex = 'female ')) -- insert a piece of data into student and use a function to verify whether the insertion is correct. create or

SQL> SELECT deptno FROM emp WHERE mgr = 7698 OR job = 'salesman' ORDER BY 1; DEPTNO ---------- 30 30 30 30 30SQL> SELECT deptno FROM emp WHERE mgr = 7698 2 UNION 3 SELECT deptno FROM emp WHERE job = 'salesman' 4 order by 1; DEPTNO ---------- 30SQL>

Create a primary key (example) SQL> alter table emp_ogg add constraint PK_empno primary key (empno ); -- Create a primary key Queries the constraints of a table.SQL> desc user_constraints;   Name Null? Type ---------------------------------------

Customize a mysql close script according to the working environment   --- 1. Save As/usr/local/mysql/scripts/mysql_env.ini # Set mysql init variablesMYSQL_USER = system # mysql UsernameMYSQL_PASS = 'Password' # mysql logon User password # Check

I. Basic Concepts In a database, the two basic operations on a data are write and read. The distribution has two types of lock control: exclusive lock (X lock) and shared lock (S lock ). Exclusive lock (x lock): If transaction T adds X lock to data

Problem description: [Celladmin @ vrh4 ~] $ CellcliCellCLI: Release 11.2.3.2.0-Production on Sat Jun 14 09:11:08 EDT 2014 Copyright (c) 2007,201 2, Oracle. All rights reserved.Cell Efficiency Ratio: 1 CellCLI> create celldisk all CELL-02559: There

I introduced the use of triggers in my previous blog, and also mentioned that triggers are a special stored procedure. What is a stored procedure? They What are the differences between the two? In fact, the main difference is that the trigger is

Oracle11g RAC construction in linux (9) 8. Create an ASM warehouse Perform operations on the GUI [Root @ node1 ~] #Su-grid [Grid @ node1 ~] $Asmca // Create two disk groups: Data File disk groups and fast recovery disk groups [Grid @ node1 ~]

FeaturesEvery document in the schema-free MongoDB is a JSON object. Therefore, you do not need to predefine the structure of a set. Each document in the set can have a different structure.By default, all write operations for asynchronous writing to

Reprinted please indicate the source: http://blog.csdn.net/guoyjoe/article/details/30839817 ######### Preparations before recovery1. Perform a Hot Backup select 'alter tablespace '||tablespace_name|| ' begin backup;' ||chr(10)|| 'host cp '|