Oracle Primary Knowledge

This article for the learning process of personal experience and summary, non-authoritative, only for reference sharing

Oracle database, currently one of the mainstream databases, why is one of the mainstream database, there are some mainstream database but verbose (Mysql,db2,sql server,sybase)

1, the first superior performance is undeniable

2, have a unique table space, logic clearer, more active

3. Distributed management, easy coordination

4, good support big data format and so on

Say some meaningful versions of Oracle, then in the summer of 1979, the RSI (Oracle predecessor) released Oracle second Edition, followed by the birth of Oracle 8i in September 1997, the same year as the June release of Oracle 8,oracle The birth of 8i means that the database supports the Internet, and I is the abbreviation of the Internet. September 2003 after 6 years after the Oracle 10g, the same version of the update added new features grid computing, the meaning of G is gird abbreviation, the database also has the ability to grid computing, after 4 that year on July 11, 2007, the realization of the life cycle management Oracle Release of the 11g release.

Here are a few database terms:

1, data: The book has its own gold house, the book has its own Yanruyu, the book is data, the same value. In the database is the most basic storage object, the format can be sound, pictures, text, media and so on stored in the database is the data, but also the basic purpose of building a database.

2, Database: Database, this library is the storage warehouse, is true real existence, built on the computer disk equipment, to file the way to store, file format by the manufacturer. Combined with the previous learning computer, then disk for block storage (SCSI, etc.), it can be said that the storage of the smallest unit is block, do not discuss.

3, database management: Since there is data stored in the database, we always have managers to plan and organize, users can not directly manipulate the file, so the security risks are very high, the same is not possible. At this time, the manufacturer's own management tools or GUI tools for the user interface, through the database management to a series of operations on the database.

4, relational database: relational database, relational tables and tables can be correlated with each other, using. The same table between the data independent, high cohesion, so that relatively good data security, use time through the operation of Database Management Association is currently the mainstream database type has been.

Talk about installation attention (main idea)

1, when the Oracle installation to check whether the hardware support, high hardware requirements, physical memory 1G, disk space detection and so on

2, based on the nature of Oracle database, in use must be a growing process, in the initial installation should consider the subsequent disk size

3, the Oracle installation path does not have the appearance of Chinese characters, because the installation path is not better to support

Objects in the database:

People who have learned programming are more familiar with the design of OA mode, the database is also supported and the object has many

1, Users: User Management role, through different permissions control to achieve different operations and management

2. Table: Database objects, consisting of rows, each row consists of columns

3, Index: is to greatly improve the efficiency of the query, the order of database tables established, the index of each row

4, Function: And most of the same, for example, in a large number of complex query SQL statements, the use of functions will greatly improve efficiency, follow the rules to return the process code

5, Stored procedures: complete a set of specific sets of SQL statements, stored in the database, only need to compile a follow-up does not need to compile, through the procedure name to call the process

6, Trigger: Trigger to listen to the name is triggered only effective, class in the listener, the essence is to execute a specific block of task code, when the database listens to an event, will activate the event and execute code block

What happens to databases, data instances, and SIDS (not particularly in depth)

The database has been introduced before, after installation we go to the Oracle's base directory, will find oracledata This folder, this is the folder that holds the database, we will see how many libraries are currently in the system, after entering the library will find the data file (DBF), log file ), control file (CBF) of these three file types, we can be sure that the database must be real, can see the file (block) stored in our computer disk.

DB instance: When the database communicates with the outside world or the outside world wants to connect the database through the database instance to interact, a database corresponds to an instance, the database instance format oracleserverinstancename, we open the service will discover Oracleserver library name, This is the database instance name service, which ensures that the instance service is generated automatically when we create the database.

SID and Oracle_sid:

The SID is called System Identifier, the SID is the unique identifier of the DB instance, usually the SID equals the instance name, and the development of databases is a logical concept, and the instance is referenced in real development by the SID.

Oracle_sid is also the environment variables of Oracle, we sqplus/as SYSDBA by default on the database, through the SQL query can see the database name and instance name, path path to set, the initialization of Oracle variables and ORACLE_SID directly affected, affect the operating environment of Oracle.

Non-professional authoritative knowledge, if you have good ideas to say thank you

Oracle Primary Knowledge