http://blog.csdn.net/robinjwong/article/details/18502195
1. Relational database
A relational database is a database that uses a relational model to organize data.
The relational model was first proposed by IBM researcher Dr. E.f.codd in 1970, and in the following decades the concept of the relational model was fully developed and gradually became the mainst
Java database connection pool configuration methods (take MySQL database as an example), database connection mysqlSeveral configuration methods for Java Database Connection Pool (taking MySQL database as an example)
1. Tomcat configuration data source:
Prerequisites: You nee
A server uses php to connect to the database, but the database address uses an external ip address, resulting in occasional access to the database connection handle requires 2 seconds. the Last Post is from u011822059 to 2013-09-0311: 29: 58 Editing example: on the server, php connects to the mysql database on the serv
Can I convert a mysql database into a desktop database when PHP is used as a website using a mysql database? I developed a PHP-language Enterprise website using the mysql database and uploaded it to some space. it costs more to use the mysql database, how can I directly conv
Acid principles for relational database compliance
(1) A Atomic nature:
All operations in a transaction, either done or done, the success of the transaction is the success of all operations in the transaction, as long as one operation fails, the entire transaction fails and needs to be rolled back.
(2) C Consistency:
The database should always be in a consistent state, and the operation of the transaction w
Triggers look at me a smattering of, see a trigger blog of a brother is particularly good, after reading, I feel that the boring gourd finally enlightened. First share this sharp good article, and then My personal supplement and mind map.
Share:
Introduction to Triggers :
Triggers (trigger) is a special kind of stored procedure, its execution is not by the program call, also does not need manual operation, it is by the event to trigger, the event everybody should be very familiar with, for insta
I have two master databases, A and B.
For historical reasons, database a only allows synchronization of database AA and database BB, that is, database A creates a new database, and database B does not synchronize data.
OK. Start
Label:
Database Paradigm
when designing the relational database, we should design a reasonable relational database to conform to different specifications, and the different norm requirements are called different paradigms, and the higher paradigm database redundancy is lower.
There
MSSQL Server 2005 Restore Database Bak files, Web sites using Virtual host site will often encounter, in general, the host has an online management program, but sometimes not, you need to restore the local backup SQL database. In this case, MSSQL Server 2008 will also appear, sometimes the "backup set of database backup and the existing XX
Database SQL optimization Summary-millions of database optimization solutions, Database SQLDatabase SQL optimization Summary-millions of database Optimization Solutions
There are many tutorials on SQL Optimization on the Internet, but they are messy. I have made some preparations recently, and I will share some of
One-click force modification of the password of any Mysql database, and modification of any environment Mysql database ., Mysql database
This article uses the built-in password change function in my software to force the password of the Mysql database with one click,
During the modification process, the Mysql main pr
Problems encountered when using website management tools for Logon pages
Problems:Go to ASP. NET configuration in the "website" menu of Visual Studio 2005 and click "security". The following error message is displayed:
"A problem may occur in the selected data storage zone because the server name or creden are invalid or the permissions are insufficient. It may also be caused by the absence of the role manager function. Click the following button to redirect to the page where you can select a
The database cannot be restored. solution:
During the Restore database operation, you may be prompted that you cannot obtain the exclusive access to the database because the database is in use !!
In this case, you must first kill the threads that are using the database bef
Database is not available, check that the database exists, that the user has permission to access the database
After the local build PHP + MySQL + Apache + zo configuration, everything is OK, but to install the configuration database information, there is a "non-use of the database
"The database cannot be deleted because the database is currently in use ".
Exception Handling Summary-database http://www.cnblogs.com/dunitian/p/4522990.html Series
I was worried about this problem when I was just learning the database. I saw it again when I deleted it today. I just recorded it together:
Graphical
One
First you need to define a database interface function that can be saved as a single PHP page
functiondb_connect() {$result = new mysqli('数据库地址', '账号', '密码', '库名');//连接数据库if (!$result) { returnfalse;//连接失败 } return$result;//返回数据库对象}?>
Two
In another PHP page, the first use of the include函数 PHP page contains the above, it is necessary to ensure that the above interface functions can be called correctly
!--? php function
Reasons for inconsistent data
Data redundancy, improper concurrency control, failures, and errors.
Three Paradigms of database
1 First paradigm: Ensure that each column remains atomic
2) Second paradigm: Ensure that each column in the table is related to the primary key
3) Third paradigm: Ensure that each column is directly related to the primary key, not indirectly related
Transaction attributes
A transaction is a unit of concurrent control, a
# # #数据库的创建
Build a project
Test first to see if a new project can run successfully
Create a personcontrary package and establish a person class to implement the Basecolumns excuse, add all the table column names to this class, and declare the final variable
Create a database helper class, override the method, and build a constructor method.
# # #数据库对外的查询1. Copy the compile ' com.facebook.stetho:stetho:1.3.1 ' into the Build (app) and
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