How to read database in oracle
How to run queries in Oracle database? Open a command prompt and connect to the database. Enter the command select * from table_name, where table_name is the name of the table to be queried.
How to read Oracle database
Open command prompt
- In Windows, press Windows key R, type "cmd" and press Enter.
- In macOS, open the Terminal application.
- In Linux, open a terminal window.
Connect to the database
- Enter the following command:
<code>sqlplus username/password\@servername:port/servicename</code>
- username:Your database username.
- password: Your database password.
- servername: The name or IP address of the database server.
- port:Port number of the database (default port is 1521).
- servicename: Database service name.
Example:
<code>sqlplus scott/tiger@localhost:1521/xe</code>
Run the query
After connecting to the database, you can run queries to retrieve data .
- Enter the following command:
<code>select * from table_name;</code>
- table_name: The name of the table to be queried.
Example:
<code>select * from emp;</code>
Other useful commands
- desc Table name: Display the structure of the table.
- insert into table name (field name 1, field name 2, ...) values (value 1, value 2, ...): Insert a new record.
- update table name set field name 1 = value 1, field name 2 = value 2, ... where condition; : Update record.
- delete from table name where condition: Delete records.
The above is the detailed content of How to read database in oracle. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

In addition to SQL*Plus, there are tools for operating Oracle databases: SQL Developer: free tools, interface friendly, and support graphical operations and debugging. Toad: Business tools, feature-rich, excellent in database management and tuning. PL/SQL Developer: Powerful tools for PL/SQL development, code editing and debugging. Dbeaver: Free open source tool, supports multiple databases, and has a simple interface.

To query the Oracle tablespace size, follow the following steps: Determine the tablespace name by running the query: SELECT tablespace_name FROM dba_tablespaces; Query the tablespace size by running the query: SELECT sum(bytes) AS total_size, sum(bytes_free) AS available_space, sum(bytes) - sum(bytes_free) AS used_space FROM dba_data_files WHERE tablespace_

Solutions to Oracle cannot be opened include: 1. Start the database service; 2. Start the listener; 3. Check port conflicts; 4. Set environment variables correctly; 5. Make sure the firewall or antivirus software does not block the connection; 6. Check whether the server is closed; 7. Use RMAN to recover corrupt files; 8. Check whether the TNS service name is correct; 9. Check network connection; 10. Reinstall Oracle software.

To create an Oracle database, the common method is to use the dbca graphical tool. The steps are as follows: 1. Use the dbca tool to set the dbName to specify the database name; 2. Set sysPassword and systemPassword to strong passwords; 3. Set characterSet and nationalCharacterSet to AL32UTF8; 4. Set memorySize and tablespaceSize to adjust according to actual needs; 5. Specify the logFile path. Advanced methods are created manually using SQL commands, but are more complex and prone to errors. Pay attention to password strength, character set selection, tablespace size and memory

There are no shortcuts to learning Oracle databases. You need to understand database concepts, master SQL skills, and continuously improve through practice. First of all, we need to understand the storage and management mechanism of the database, master the basic concepts such as tables, rows, and columns, and constraints such as primary keys and foreign keys. Then, through practice, install the Oracle database, start practicing with simple SELECT statements, and gradually master various SQL statements and syntax. After that, you can learn advanced features such as PL/SQL, optimize SQL statements, and design an efficient database architecture to improve database efficiency and security.

To view Oracle databases, you can use SQL*Plus (using SELECT commands), SQL Developer (graphy interface), or system view (displaying internal information of the database). The basic steps include connecting to the database, filtering data using SELECT statements, and optimizing queries for performance. Additionally, the system view provides detailed information on the database, which helps monitor and troubleshoot. Through practice and continuous learning, you can deeply explore the mystery of Oracle database.

The procedures, functions and packages in OraclePL/SQL are used to perform operations, return values and organize code, respectively. 1. The process is used to perform operations such as outputting greetings. 2. The function is used to calculate and return a value, such as calculating the sum of two numbers. 3. Packages are used to organize relevant elements and improve the modularity and maintainability of the code, such as packages that manage inventory.

OracleGoldenGate enables real-time data replication and integration by capturing the transaction logs of the source database and applying changes to the target database. 1) Capture changes: Read the transaction log of the source database and convert it to a Trail file. 2) Transmission changes: Transmission to the target system over the network, and transmission is managed using a data pump process. 3) Application changes: On the target system, the copy process reads the Trail file and applies changes to ensure data consistency.
