文章目录
- [The PostgreSQL system architecture](#The PostgreSQL system architecture)
- [create database and delete it in PostgreSQL](#create database and delete it in PostgreSQL)
The PostgreSQL system architecture
The PostgreSQL system architecture is a typical client/server model, involving a server process and the user's client. The server process, called postgres, is responsible for managing the database files, receiving connection requests from clients, and performing data operations on demand. Client applications can exist in various forms, such as web clients, console clients, and graphical clients.
It is important to note that the PostgreSQL server produces processes to handle a massive number of connections at the same time by forking a new process for each connection.
create database and delete it in PostgreSQL
The 'createdb database_name' command is a PostgreSQL utility for creating new databases. If a database is no longer needed, you can use the 'dropdb database_name' command to remove it.
Accessing a database is straightforward---simply use the 'psql' command to enter its console. For example: psql my_db.
As you might expect, you can type SQL statements directly into the psql console. Additionally, various meta-commands are available within it.
By the way, although PostgreSQL is primarily designed as a relational database management system, it also supports more types of databases, such as hierarchical and object-oriented databases.
We can create a simple table as follows:
CREATE TABLE department (
name varchar(80),
id int,
manager_id int
);If you no longer need the table, you can delete it using the DROP TABLE table_name command.
createdb database_name 命令是 PostgreSQL 用于创建新数据库的实用工具。如果某个数据库不再需要，可以使用 dropdb database_name 命令将其删除。
访问数据库非常简单------只需使用 psql 命令即可进入其控制台。例如：psql my_db。
正如你可能想到的，你可以直接在 psql 控制台中输入 SQL 语句。此外，控制台内还提供了各种元命令。
顺便一提，尽管 PostgreSQL 主要设计为关系型数据库管理系统，但它也支持更多类型的数据库，例如层次型数据库和面向对象数据库。