1. Introduction of database
In the past, data was stored in memory using variables, arrays, and objects, and memory can only store data temporarily. If we want to store data for a long time, use files to store data on disk, which is inconvenient to access and manage data, so we can use database to store data.
2. Basic concepts of database
2.1 Database (database, referred to as DB)
A warehouse that accesses data, manages data, and realizes data sharing with a certain organization and structure. The data of the database is stored on the hard disk of the computer, and the data can be stored for a long time.
2.2 The role of the database
Access data, manage data, generate new data, and share data.
2.3 Classification of databases
2.4 Database Management System (DataBase Management System, DBMS):
The essence is an operation and management database software.
2.5 Administrator (DBA)
Professionals dedicated to managing and operating databases.
2.6 Database System (DBS)
It consists of database, database management system and administrator.
2.7 Composition of relational database
Tables, relationships between tables, and object composition.
3. Oracle database concept
It is one of the most popular relational databases and is the core product of Oracle Corporation. The software of Oracle is free, and the service is charged.
3.1: History of oracle.
3.2. The working principle diagram or main components of oracle database:
3.3: Oracle database concept: refers to the collection of data stored on disk.
Physically manifested as data files, log files, and control files.
Logically exists in the form of table space.
3.3.1: Database instance: Each started database corresponds to a database instance, which is used to access and control the database. In order to run the database, the combination of all the processes run by the Oracle system and the allocated memory structure
3.3.2: Data file: The extension is .DBF, which is used to store database data. There is no one-to-one correspondence between database tables and data files
3.3.3: Control file: the extension is .CTL, which is a file necessary for database startup and operation. It contains 3 control files by default, and each control
The file contents are the same.
3.3.4: Log file: The extension is .LOG, which records all changes to the data. It is used circularly between multiple log file groups.
3.3.5: Tablespace: Each Oracle database is composed of several tablespaces. All the content created by the user in the database is stored in the tablespace. When creating a database, several tablespaces are automatically created.
3.3.6. sys and system users of Oracle database
1. Uninstall and install Oracle
4.1: Oracle database installation environment:
4.2: Oracle installation
4.2.1: Install the oracle database management system first, and at the same time install the database and monitor. Note: Chinese paths should not appear in the installation files and installation paths.
The installation is complete, click close, open the sql/plus client in the start menu -> enter sys/password as sysdba to log in successfully.
4.2.2: Install the database separately
4.2.3: Separately configure monitoring
4.3: Oracle uninstallation:
4.3.1: Software uninstallation
4.3.2: Delete the oracle registry
4.3.3: The steps to delete the residual files of oracle are as follows.
4.4: Install third-party software: PLSQL Developer
After installing the third-party software, you can use the third-party software to test the connection to the oracle database
2. Stop, start and log in the oracle service
5.1. Start and stop of oracle service
5.1.1: Start/close the service: right mouse button on the taskbar - "select task manager - "details information - "service - "oracle right click to start/stop.
5.1.2: Start/stop service: Right click on my computer - "management -" service - "oracle right click to start/stop.
5.1.3: Start/shut down the service: run cmd as an administrator-> enter the command net stop/start oracle service name;
5.2: Oracle login method:
5.2.1: The first type of login: open the sql plus client-"enter account/password as login identity.
5.2.2: The second type of login: use PLSQL Developer to connect and enter the account number, password, connection database name, login role, test the connection is successful, and you have logged in after confirming.
5.2.3: The third type of login: use Navicat for oracle to create a connection and enter the password, test the connection is successful, and you have logged in after confirming.