Common database systems compare Oracle databases

The ORACLE tutorial you are looking at is: common database systems compare Oracle databases. When it comes to databases, the first company that comes to mind is usually Oracle. The company was founded in 1977 as a database development company.
Oracle is leading the way in the database space 1. Relational databases were first moved to desktop computers in 1984. And then the next version of Oracle,
Version 5, first introduced the distributed database, customer/server structure and other new concepts. Version 6 of Oracle pioneered row locking and symmetric multiprocessing computers
The support of the... The latest Oracle8 features the addition of object technology as a relational - object database system. Currently, ORACLE products cover large, medium and minicomputer
With several dozen models, the Oracle database is one of the most widely used relational data systems in the world.

Oracle relational database products:

Oracle database products have the following excellent features.

(1) compatibility

Oracle products use standard SQL and have been tested by the U.S. national institute of standards and technology (NIST). It is compatible with IBM SQL/DS, DB2, INGRES, IDMS/R, etc.

(2) portability

Oracle products run on a wide range of hardware and operating system platforms. Can be installed in more than 70 different large, medium and small machines; Can be in VMS,
DOS, UNIX, WINDOWS and other operating systems.

(3) connectability

Can be connected to a variety of communication networks, support a variety of protocols (TCP/IP, DECnet, LU6.2, etc.).

(4) high productivity

Provides a variety of development tools, can greatly facilitate users to carry out a step in the development.

(5) openness

Oracle has good compatibility, portability, connectivity and high productivity. Oracle RDBMS has good openness.

ORACLE products mainly include database server, development tools and connection products.

Database server

The latest version is 8, but the most widely used is 7. Version 7 features the following features:

(1) multi-process, multi-clue architecture

Multi-process, multi-thread architecture. Oracle7 consists of one to multiple thread processes, multiple server processes, and multiple background processes. The lead process is responsible for listening
The user requests, chains the user request into the memory request queue, and returns the result of execution in the reply queue to the corresponding user. The server process is responsible for processing the request queue
The user requests and chains the results to the reply queue. The number of threads and threads can be dynamically adjusted based on the current workload. Oracle7's process structure can be sufficient
The ability to make use of multiple processors on parallel machines, but because the threads are simulated by processes and scheduled by the operating system, this somewhat weakens the advantage of low thread overhead
The more sex.

(2) to improve the performance of core technologies

Oracle7 improves its core technology. Its concurrency control mechanism is more sophisticated, including unrestricted row level blocking, uncontested queries, and sequential number generation of clues
System. The Shared SQL Cache was added to the Shared memory buffer to improve the operation efficiency.

(3) high availability

Oracle7 provides online backup, online restore, mirroring and other mechanisms to ensure high availability and fault tolerance.

(4) implementation of SQL

SQL of Oracle7 complies with ANSI/ISO SQL 89. Integrity constraints conform to the entity integrity and referential integrity constraints of the ANSI/ISO standard. Provide Angle based
Color safety.

A role is a collection of 1 group of permissions. With the concept of roles, the security management mechanism can combine some permissions on a table or other database object and combine them
Assign a role. Simply grant the role to one user or group of users as needed, which reduces the burden and cost of the security mechanism.

For the cluster and MPP parallel computer platform, Oracle7 provides a parallel server option for disk sharing. At the same time, Oracle7 is also SMP, cluster and MPP flat
The platform provides parallel query options to implement parallel query, parallel data loading and other operations.

Oracle7 provides distributed database functionality through distributed options. Its distributed option provides multi-site distributed query and multi-site update function with bits
Transparency and site autonomy, global database names, remote procedure calls.

The development tools

The development kits provided by Oracle are Developer / 2000, Designer / 2000, Discover / 2000, Oracle Office, etc.
Analysis, design to the concrete realization of each link.

Developer / 2000 includes:

Oracle Forms is used to quickly generate complex screen-based applications. It has an GUI interface and multimedia capabilities, mainly for manipulating data and queries.

Oracle Reports is a tool for generating reports quickly. Can generate various complex reports, can also process multimedia information.

Oracle Graphics is used to generate various graphical applications.

Oracle Books is used to generate online documents.

Designer / 2000:

This is the CASE tool provided by Oracle. The tool helps users model, analyze, and design complex systems. It can also help users draw ER diagrams and work
It can be layered graph, data flow graph and square matrix graph.

Discover/2000:

This is an OLAP tool that supports data warehouse applications. It can mine the historical data to find the development trend and the general situation of different levels
The data is analyzed to find detailed information about the business.

Oracle Office is designed for office automation and can handle enterprise-wide message reception and delivery, scheduling, calendar management, directory management, and spelling
Check.