The selection principle of database

Data | database
First, the principle of database selection
1, stable and reliable (high-availability)
Database preservation is the enterprise's most important data, is the core of enterprise application, stable and reliable database can ensure the application of the enterprise year-round operation, and not because the database downtime and suffer losses. Enterprise Informatization can promote productivity, but if the choice of unstable products, often affect the normal operation of business production, the actual effect is likely to drag the enterprise back. Whether planned (database maintenance, normal work) or unexpected downtime will bring huge losses to enterprises, which means that enterprises to reduce low income, to lower productivity, to lose customers, in the fierce competition in the enterprise lost confidence. The stability and reliability of information system is composed of many factors, including network, host, operating system, database and application software and so on, these factors have a certain dependence on each other, therefore, we should consider these problems in the selection of Enterprise informatization. In the database, the database should be equipped with disaster recovery, system error recovery, artificial operation error recovery functions, while minimizing the planned maintenance downtime of the database.
2, Scalable (high-scalability)
The application of enterprise is continuously deepened and expanded, the amount of data and the amount of transaction processing per unit time will increase gradually. It would be inappropriate to require an enterprise to purchase a set of information systems sufficient to meet the needs of development in the years to come, since it actually means that businesses spend a lot more money than they can to maximize the efficiency of their information equipment, resulting in waste of resources. A better solution is to purchase a set of low, functional application system, when the future business needs can be easily extended to the system, so that the processing capacity of the system gradually increased to meet the needs of business processing. Implementation to the database is to choose a good scalability and flexible configuration features of the product, whether the host system of memory or hard disk expansion or cluster system expansion, can be used by the database, thereby improving the system's processing capacity.
3. Safety (Security)
The security of a database is the protection of the database to prevent data disclosure, alteration, or destruction caused by unlawful use. Security issues are not unique to the database system, and all computer systems have this problem. There are a lot of important data stored in the database system, and they are shared with many end users, so the security problem is more prominent. It is one of the important indexes of the database system whether the system safety protection measures are effective. Database security control mainly through the user identification and identification, access control, view mechanism, audit, data encryption and other mechanisms to complete.
4, a wealth of development tools
Whether it is a good hardware platform or a powerful database management system, can not directly solve the end-user application problems, enterprise information work should be implemented to develop or purchase suitable for enterprise management of the application software. Most of the current database management systems follow the Unified interface standard, so most of the development tools can be developed for many kinds of database applications. Of course, database vendors often have their own development tools, such as the Developer2000 of Sybase's Powerbuilder,oracle company, and Ms Visual Studio. These development tools have their pros and cons, but there is no doubt that the selection and database of the same manufacturer's products will be more conducive to the development of application software and future unified technical support.
5. Service Quality
In today's highly developed information competition, database vendors completely rely on product quality to impress users of the era has ceased to exist, the quality of the database products in the gap gradually narrowed, and the user choice of products is an important factor in the positioning of the manufacturer's technical services. Because after you buy the database system, you are faced with complex software development, database maintenance, database product upgrades and so on, you need to get database vendor training, various ways of technical support (telephone, user site) and consulting. The quality of service of database manufacturers will directly affect the work of enterprise information construction.


2, Oracle
To bring up the database, the first company to think of, is usually oracle. The company was founded in 1977 and was originally a company specializing in the development of databases. Oracle has a leading position in the database field. In 1984, the relational database was first transferred to the desktop computer. Then Oracle's next version, version 5, pioneered the new concepts of distributed databases, client/server architectures, and so on. Oracle version 6 first-line locking mode and support for Chenduo processing computers The newest Oracle8 mainly adds object technology and becomes relational-object database system. Oracle is currently one of the most widely used relational data systems in the world, with dozens of models of large, medium and small machines.
Oracle database products have the following excellent features:
Oracle 9i continues to focus on the Internet, as Oracle 8i, by providing a range of specific features and packages for the e-business environment. In addition, Oracle 9i adds new features and capabilities to expand investment in mission-critical infrastructure. Here we introduce the new features of Oracle 9i in some key development areas:
Achieve Continuous data availability
Oracle 9i dramatically expands Oracle's position on Internet database availability. These include:
(a) world-leading data protection environment
Oracle 9i includes a number of new features that improve data protection. In addition to the emphasis on existing standby products, a framework for monitoring, automation and control is included. Many of the tasks associated with managing standby data are also automated, including initialization implementations, error jumps, and easy handover between master and slave. Logminer is also enhanced in Oracle 9i to provide a comprehensive, sql-based log analysis.
(b) Online data evolution
Oracle 9i includes a new online restructuring and redefinition of the architecture, which provides a more robust restructuring. Oracle 9i currently allows the "Create Table as Select" operation to be connected to the machine. In the new architecture, the contents of the table are copied into a new table, and the database tracks updates to the original table while the content is being copied. With the new architecture, you can change any physical property of a table, and many other logical properties can be changed. Oracle 9i also supports the online creation, rebuilding, and so on of the tier indexes on the indexing table. Administrators can also quickly stop a database to perform operations that require inactive transactions.
(c) Accurate database repair
Oracle 8i contains very complete recovery capabilities, and Oracle 9i extends them by making these features more powerful and accurate. Oracle 9i includes a better way to prevent and improve disk damage. Oracle 9i can also recover from the crash faster by using the new two-pass recovery algorithm, which ensures that only blocks that need to be processed can read and write data files from the data file.
(d) Self-service error correction
Oracle 9i contains powerful techniques for handling human errors, including the ability to authorize end users to correct their own errors in a more accurate, efficient, and easier manner. To change errors, end users need to be able to identify errors by viewing the history of changes, and they need to be able to exit the error by restoring the data to the data before the error occurred. There are two ways to query, one is to use the Oracle 9i flashback (back-Flash) query feature to allow querying of data from a certain point in the past, one of which is to use Logminer to trace the history of changes from a log file to a database.
Scalability and performance
Oracle 9i allows e-business to be extended to tens of millions of users, and each user performs millions of of things per hour. Including:
(a) Oracle 9i real Application Clusters-cache Fusion
Oracle 9i Real Application clusters enables the application of the database for high availability, scalability, and high performance without modification. The Oracle 9i cache Fusion architecture uses the aggregation cache of all nodes in the cluster to satisfy the database request. Oracle 9i Cache Fusion transports data blocks directly from one node's cache to another's cache in read/read, read/write, and write/write contention. This is based on the previous Oracle 8i Cache Fusion execution that deals with read/write contention.
(b) Scalable session-state management
New shared memory features, improved JAVA session support, networking, and multi-line server improvements have significantly reduced the coverage required for each user on Oracle 9i-allowing more users to be hosted on the same or larger hardware platform.
(c) Optimization characteristics that play a key role in electronic commerce
Specific performance improvements in Oracle 9i focus on areas and performance that are critical to improving e-business solutions. The support for improved Pl/sql optimizations for local compilation greatly improves the performance of many applications today. For connections between application servers and Oracle 9i databases on the back end, the new features of Oracle Net Services--vi (virtual Interface, Protocol) Support performance improvement 10%. In addition, specific network interface optimizations, newly improved virtual line I/O, and unified event/wait patterns greatly improve client/server communication performance. Using OCI to redo database/database communication improves the performance of distributed databases.
Provides End-to-end security architecture
Oracle 9i continues to provide the industry's most secure application platform and deployment platform. Including:
(a) robust three-storey security
Enhanced three-tier security through proxy authentication, including X.509 license file or discriminant (DN) credit agents, support for fat JDBC, Connection Sharing for application users (fat jdbc and thin jdbc, OCI), and integration with Oracle Internet directory.
(b) standards-based PKI
The standards-based PKI for Oracle Advanced security (Advanced secure) includes the public Key certificate (PKCS) #12的支持, allowing existing PKI credits to be shared by Oreacle Wallet, This reduces the cost of PKI deployment and enhances interoperability.
(c) Deep database protection
Oracle Label Security, a product based on Viretual private database (virtual private databases, VPD), has a stronger VPD function, more granular audit, can provide more reassuring host safety. Granular auditing allows for the definition of audit policy, which enables the database to specify the access that triggers the corresponding audit event, and utilizes a flexible event handler to notify the system administrator of the event that is triggered.
(d) Improved Enterprise user security (for enterprise users)
Oracle Advanced Security's Enterprise user security has been enhanced, including the ability to provide password-based user management in Oracle Internet directory, and password management enhancements. These have facilitated improvements in user and security policy management.
(e) Data encryption
Oracle has added a data storage encryption feature that incorporates a secure random number generator (RNG) into Dbms_obfuscation_toollkit.
(f) Oracle label Security (Oracle label safety)
Oracle Label Security is a precision granular access control product. It adds a special label to the data row, providing complex and flexible label security.
(g) Oracle Internet Directory (Oracle Internet directory)
Oracle 9i supports LDAP technology to manage the network naming system and facilitate system deployment, with more than 10 or tens of thousands of users per database, regardless of whether the customer owns one or hundreds of databases.
Development platform for E-business applications
Oracle 9i continues to provide the best development platform for e-business applications and the development of traditional applications. Including:
(a) Enterprise Java Engine
In the third edition of Oracle 8i, a series of Java features have been provided, and Oracle 9i Database First edition support for Java is focused on: improving the performance of embedded Java Virtual Machine (virtual machines), providing new IDBC and SQLJ capabilities , enhanced Java stored procedures, and bug fixes to the EE container.
(b) XML supports-xml types and XDK
Oracle 9i features a number of enhanced database operations that store XML in the database through SQL and convert traditional database data to XML. Two major XML domains are supported in Oracle 9i, one is the built-in AML Developer Kit (XML Development Kit, XDK), and one is the native XML type.
(c) SQL and pl/sql improvements
SQL and Pl/sql have been improved in Oracel 9i to meet the requirements of modern development. In addition to local compilation, the overall Pl/sql compilation is improved. Support for enhancing the usefulness, inheritance, type evolution, and dynamic method allocation of objects is supported in Oracle 9i. Oracle 9i also supports new ANSI requirements, including support for case statements, ANSI-compliant links, and reserved version annotations.
Manageability
Management is one of the main improvements to Oracle 9i. The management approach taken by Oracle 9i has five aspects:
(a) Self-managing data
Oracle 9i databases manage their own undo (fallback, Rollback) segments-administrators no longer need to carefully plan and optimize the number and size of fallback segments, or worry about assigning transactions to specific fallback segments on a policy. Memory management is another area in Oracle 9i that gives significant control.
(b) Improved and streamlined operational management
Other traditional management areas of the database have also been improved. With the introduction of persistent Init.ora characteristics in Oracle 9i, parameter changes persist in multiple closures.
(c) Sophisticated, automated resource management
The introduction of database Resource Manager in Oracle 8i has been greatly enhanced in Oracle 9i, with the ability to control finer resources and add new features.
(d) Management tools and techniques
Oracle 9i also offers new features, tools, and techniques that make it a pleasure for administrators to leave little work. In Oracle 9i, Oracle Enterprise Manager continues to provide Easy-to-use management tools that support new features of the database and the entire e-business platform. To further simplify management tasks, Oracle Enterprise Manager includes guided expert diagnostics and problem solving. All basic management functions are web-based, and administrators can manage their systems directly from a Web browser.
(e) End-to-end System Management Solutions
In Oracle 9i, Oracle Enterprise Manager also allows administrators to exceed the scope of monitoring only the performance of a single target, such as a database, where administrators can monitor the response of an entire Oracle-based system and ensure that they meet the required business service-level engagements.
Windows integration
Oracle 9i is a leading position on the Windows 2000 platform. Including:
(a) integration with Windows 2000
Oracle 9i supports better integration with Microsoft Transaction Service, Microsoft Message Queuing, and Internet information Services. The PKI architecture and single signon features in Oracle 9i are also well integrated with Windows 2000, Active Directory, and Microsoft certificate Store.
(b) Development and deployment on the MS Windows platform
For Windows developers, Oracle 9i provides an enhanced local OLE DB provider. Oracle Object for Windows supports XML, database event (DB events), and Oracle 9i OCI extensions.


1, SQL Sever 2000
(1) SQL Server Development History Review
Since its launch in 1989, Microsoft SQL Server has steadily progressed from desktop to workgroup and eventually into the enterprise computer room. Microsoft SQL Server 2000 is another new and improved relational database management system that Microsoft has introduced since Microsoft SQL Server6.5 and Microsoft SQL Server7.0. The frontier enables users to quickly manage databases and develop applications. SQL Server was developed from the late the 1980s, the earliest originating from the 1987 Sybase SQL Server. In 1988, Microsoft, Sybase, and aston-tate the product to the OS/2. The Aston-tate company later withdrew from the product development, while Microsoft and Sybase signed a common development SQL Server porting to Windows NT. The results of the two companies ' common development were the release of SQL Server for Windows NT operating systems. After the release of SQL Server 4, Microsoft and Sybase have stopped collaborating on the development of SQL Swrver. MICROSOFT is committed to SQL Server development on the Wisows NT platform, while Sybase is committed to SQL Server Development on UNIX platforms. SQL SERVER6. Version 0 is the first version that was developed entirely by Microsoft Company. 1996, MICROSOFT released a huge change in 7. Version 0. This version has undergone a fundamental change in data storage and database engine. After two years of efforts to develop, in September 2000, the cloth SQL SERVER 2000. From SQL SERVER 7. The 0 to SQL SERVER 2000 change is incremental, not from 6. 5 to 7. 0 changes so much, just in SQL SERVER 7. 0 on the basis of the enhancement.
(2) Current SQL Server market occupancy
As a database developed by Microsoft on the Windows Family platform, SQL Server has been favored by many users for its ease of use. Unlike FoxPro, access small databases, SQL Server is a full-featured database management system. It includes features that support the development of the engine, standard SQL language, extended features such as replication, OLAP, analytics, and so on. And like stored procedures, triggers and other features, but also large databases have. So it has become the leading product in the current market.
SQL Server is the fastest growing relational database, with revenue growing at 45%, three times times the overall relational database market. SQL Server is the most popular relational database on the Microsoft Windows platform, accounting for 38% of the market share. (gartner,2001 year June) SQL Server is the most popular Web database with a market share of 68%. (Zona research,2000 year January) there are more than 2000 applications running on SQL Server. The survey found that SQL Server has a lower cost of ownership than products such as Oracle, and currently has more than 85,000 trained SQL Server database administrators (DBAs). The above metrics show the outstanding performance of SQL SERVER in the current market.
(3) Performance comparisons for Microsoft SQL Server 2000 and SQL Server 7.0. Microsoft SQL Server 2000 extends performance, reliability, quality, and ease of use on the basis of SQL Server 7.0. SQL Server 2000 contains a number of new features that make it an excellent database platform for e-business, data warehousing, and online business solutions. Its enhanced features include support for rich Extensible Markup Language (XML), integrated Analysis Services, and easy database management (see below for details). In summary, the new features provided by SQL Server 2000 have a significant advantage over SQL Server 7.0 for customers who want to ensure that the database solution is scalable, reliable, and flexible.
(4) The limitations of SQL Sever 2000. Because SQL SERVER is only limited to Microsoft's operating system. makes it impossible for SQL SERVER to benefit from the good features of other operating systems. UNIX is superior to Windows nt/2000 in areas such as enhanced parallel architectures or enterprise computing.