oracle management tutorial

Oracle is currently one of the largest relational database management systems (RDBMS) in the world and is widely used in enterprise-level applications, data warehouses, cloud computing and other fields. Learning Oracle database management skills is a very necessary skill for database administrators and IT practitioners.

This article will introduce you to the basic concepts and techniques of Oracle database management, including database creation, table creation and management, user and permission management, backup and recovery, performance tuning, etc. It has certain reference value for both beginners and experienced Oracle DBAs.

1. Creation and configuration of Oracle database

First of all, before creating the Oracle database, you need to install the Oracle database software. This process is relatively simple and will not be described in detail. Let's take a look at how to create an Oracle database.

1. Create a database instance

In Oracle, a database instance is the basic unit for managing the database, including SGA (shared memory area) and background processes. The steps to create a database instance are as follows:

1) Edit the initialization parameter file (init file). This file is used to configure the initial parameter settings of the instance. Place this file in the $ORACLE_HOME/dbs directory.

2) Start the instance:

$ sqlplus /nolog

SQL> connect / as sysdba

SQL> startup pfile=$ORACLE_HOME/dbs/initdb .ora;

The "db" here refers to the database name, and initdb.ora is the initialization parameter file of the database instance.

2. Create table space

In Oracle, a table space is a logical container for storing user data in the database. Therefore, before creating a table, you need to create a tablespace. The steps to create a table space are as follows:

1) Open SQL Plus and connect to the Oracle database:

$ sqlplus /nolog

SQL> connect / as sysdba

2) Create a new tablespace:

SQL> CREATE TABLESPACE tablespace_name DATAFILE 'path/to/datafile' SIZE 10M AUTOEXTEND ON NEXT 10M MAXSIZE unlimited;

where tablespace_name is the name of the tablespace , path/to/datafile is the full path of the Oracle physical file, SIZE is the initial size of the table space, AUTOEXTEND ON indicates automatic growth of the space, NEXT is the size of the file extension, and MAXSIZE is the maximum size of the file.

Note: The NOLOGGING option should not be used unless you have backed up your data files.

3. Create user

In Oracle, the user is the subject who uses the database and manages database objects. Users can own one or more objects (such as tables, views, procedures, etc.). The steps to create a user are as follows:

1) The user to be created must have the sysdba role or a role with CREATE USER permissions.

2) Open SQL Plus and connect to the Oracle database:

$ sqlplus /nolog

SQL> connect / as sysdba

3) Create a new user ：

SQL> CREATE USER username IDENTIFIED BY password DEFAULT TABLESPACE tablespace_name QUOTA 100M ON tablespace_name;

where username is the user name to be created, password is the user password, and tablespace_name is the default for a user tablespace, QUOTA specifies that users control their space usage in the tablespace.

4. Authorization and Permission Management

Permission management in Oracle database is very important because it ensures user security and database confidentiality. The following are common operations for authorization and rights management:

1) Authorize to user:

GRANT privilege_name ON object_name TO user_name;

2) Revoke user’s permission:

REVOKE privilege_name ON object_name FROM user_name;

3) View the user's permissions:

SELECT * FROM USER_SYS_PRIVS WHERE USERNAME='username';

4) View User-owned objects:

SELECT * FROM USER_OBJECTS WHERE OBJECT_TYPE='TABLE';

5. Backup and Restore

After creating the database, backup and Restoring the database is a very important operation. When the database system administrator or user accidentally deletes data or fails, the data can be restored to ensure data security.

1) Database backup

Using Oracle backup tools can simplify the backup process. When backing up an Oracle database, the following are common backup options:

• Full backup: Back up the entire database
• Incremental backup: Back up changed data
• Differential backup : Changes between the backup and the last full backup

The example command to back up the database is as follows:

$ rman target /

RMAN> BACKUP DATABASE;

This command means to back up the entire database.

2) Database recovery

When an accident occurs, the recovery program must implement the following steps:

• Recover data files
• Recover control files
• Determine the media that needs to be restored
• Execute the recovery command

The example command for database recovery is as follows:

1) Close the database instance:

SQL> shut immediate;

2) Start the instance:

$ sqlplus /nolog

SQL> connect / as sysdba

SQL> startup mount;

3) Start recovery:

RMAN> RECOVER DATABASE;

4) Open the database:

RMAN> ALTER DATABASE OPEN;

6. Performance Tuning

Performance tuning of Oracle database is a headache for many database administrators and IT practitioners. In Oracle database, the following common techniques can be used to improve performance:

1) SQL tuning

First, ensure that the SQL statement is optimized. You can use the SQL tuning tools provided by Oracle, such as SQL Tuning Advisor and SQL Access Advisor. In addition, you can also manually analyze the SQL statement to find the problem and modify the SQL code to improve performance.

2) Ensure that the index is available

Index is a common technique used to improve database query performance. In Oracle, you can use the index optimizer to generate the best execution plan.

3) SGA and PGA tuning

SGA and PGA are key components of the Oracle database. SGA (Shared Memory Area) stores shared memory such as cache pools and dictionary caches, while PGA (Private Memory Area) stores data in the server process. Through reasonable configuration and adjustment of SGA and PGA, the performance of the system can be improved.

7. Summary

This article introduces the basic concepts and techniques of Oracle database management, including database creation, table creation and management, user and permission management, and backup and recovery, performance tuning, etc. These tips are necessary for database administrators and IT practitioners.

Of course, Oracle database management is a broad field, and there are many more advanced technologies that need to be mastered. However, as long as you understand these basic skills, you can help you better manage and optimize your Oracle database to ensure its efficient, stable and safe operation.

The above is the detailed content of oracle management tutorial. For more information, please follow other related articles on the PHP Chinese website!