<> One ,SQL Server Basic introduction
SQL Server yes Microsoft Relational database management system launched by the company . It has the advantages of easy to use, good scalability and high degree of integration with related software , Straddle slave operation Microsoft
Windows 98 Laptop to run Microsoft Windows 2012 Large multiprocessor servers and other platforms .
Microsoft SQL Server Is a comprehensive database platform , Use integrated business intelligence (BI) Tools provide enterprise level data management .Microsoft SQL
Server Database engine provides more secure and reliable storage function for relational data and structured data , Enables you to build and manage highly available and high-performance data applications for your business .
<>1.2, Application scope
SQL Server Application scope of , It has a certain relationship with its specific version , Basically ： Enterprise Edition （Enterprise Edition）
（ Business of large and medium-sized enterprises ）; Standard Edition （Standard Edition） （ Small business ）; Development version （Developer Edition）
（ development company , Used by developers ）; Personal Edition （Personal Edition） （ Used by developers ）;MSDE 2000（Microsoft SQL Server
2000 Desktop Engine）（ Simple stand-alone database , Developer development test use ）
<>1.3, Advantages and disadvantages
(1) Strong expansibility ： When the system needs higher database processing speed , Simply add a database server Can be extended .
(2) Maintainability ： When a node fails , The system will automatically detect the failure and transfer the application of the failed node , Ensure the continuous work of database .
Security ： Because the data will be synchronized on multiple servers , Data set redundancy can be realized , Security through multiple data . In addition, it successfully put the database into the intranet , Better protection of database security .
(4) Ease of use ： Completely transparent to applications , What the cluster exposed is a IP
Ⅰ. Can't follow Web The processing power of the server distributes the load .
Ⅱ. Load Balancer ( Control end ) fault , The whole database system will be paralyzed .
<>1.4, Basic grammar
increase ：insert into Target data sheet select * from Source data table " ( Add records from the source data table to the target data table )
Delete ：delete from data sheet where Conditional expression
change ：update data sheet set field 1= value 1, field 2= value 2 …… field n= value n where Conditional expression
check ：select * from data sheet where Field name = field value order by Field name [desc]
<> Two ,MySQL Basic introduction
MySQL Is a relational database management system , By Sweden MySQL AB Company development , Currently belongs to Oracle Subsidiaries .MySQL The most popular relational database management system , stay
WEB Application MySQL It's the best RDBMS (Relational Database Management System, Relational database management system )
One of application software .MySQL
It is an associated database management system , Associated database saves data in different tables , Instead of putting all the data in one big warehouse , This increases speed and flexibility .MySQL Used SQL
Language is the most commonly used standardized language for accessing database .
<>2.2, Application scope
Web Website system ： Simple installation and configuration , Superior performance , Open Source .
Log management system ： Efficient insertion and query capabilities , If the design is better , in use MyISAM When storing the engine , The two can not lock each other , Achieve high concurrent performance .
Data warehouse system ： In the need of large storage space and efficient data analysis , At present, there are basically three ways to solve this problem ：1, Using expensive high performance hosts to improve computing performance , Improve with high-end storage devices I/O performance , Ideal effect , But the cost is very high ;2, Low cost by copying data to multiple hard disks with large capacity pcserver upper , To improve overall computing performance and I/O ability , Good effect , Storage space is limited , Low cost ;,3, By splitting data horizontally , Use multiple cheap ones pcserver And local disks to store data , Every machine has only a part of all the data , Solve the problem of data volume , All pcserver Parallel computing together , It also solves the problem of computing power , Allocate the operation tasks of each machine through the intermediate agent , It can solve both computing performance problems and problems I/O Performance issues , It's also cheap . For the second and third ,MySQL All have great advantages （ Simple replication across domains , Free Admission ）.
Embedded system ： The biggest limitation of embedded environment to software system is the limited hardware resources , Software system running in embedded environment , Must be lightweight and low consumption software .MySQL There are versions specifically for embedded systems .
<>2.3, Advantages and disadvantages
1, support 5000 Data warehouse of 10000 records ;2, Suitable for all platforms ;3, Open source software , Quick version update ;4, Excellent performance . Purely in terms of performance ,MySQL It's pretty good , Because it contains a default desktop format MyISAM.MyISAM
The database is very compatible with the disk and does not take up too much CPU And memory .MySQL Can run on Windows System without conflict , stay UNIX Or similar UNIX It is better to run on the system . You can use the 64 Bit processor for additional performance . because MySQL It's used inside a lot of times 64 Integer processing of bits ;5, cheapness
Lack of functions of some stored programs , Unfamiliar keywords are not supported , Use default port IP（ It's also an advantage ）, Vulnerable to hackers .MyISAM（MySQL Default storage engine for , The other is innoDB） Transaction not supported .
<>2.4, Basic grammar
MySQL The basic syntax and SQL Server Basically the same .