In this article, we will learn how to create a table in PostgreSQL. I am going to explain the following topics: The syntax of the CREATE TABLE statement and the options that we can use while creating it The column and table constraints are supported by PostgreSQL ...
After the columns are defined, table-wide constraints may be declared. Table-wide constraints can be either UNIQUE, PRIMARY KEY, CHECK, or REFERENCES. How to Create a Table in PostgreSQL Let's create a test table to practice on. We will create a table called "pg_equipment" that...
You can rename a table in PostgreSQL by using the ‘ALTER TABLE’ command as follows: ALTER TABLE tablename RENAME TO preferredtablename; If the table name has odd characters in it, then a syntax error might be generated which can be solved by placing the table name in double quotes: ...
PostgreSQL throws an error if you delete a non-existent table. To avoid exceptions while deleting such a situation, add the IF EXISTS parameter after the DROP TABLE clause. If you want to delete a table used in constraints, views, or any other objects, you need to specify CASCADE after th...
一、PostgreSQL on Win环境搭建 1 环境要求 2 下载PostgreSQL安装包 3 解压PostgreSQL安装包 4 下载pgadmin安装包(可选) 5 安装pgadmin(可选) 6 规划数据文件目录 7 初始化数据库集群 8 配置postgresql.conf 9 配置pg_hba.conf(可选) 10 启动、停止数据库集群 ...
InPostgreSQL, theALTER TABLEcommand performs different functionalities on a table. For example, theALTER TABLEstatement can add, drop, or update the table columns. Moreover, it allows us to add or remove constraints to a table. So, all in all, we can say that theALTER TABLEcommand is used...
Example # 1: How to Rename a Table’s Column in Postgres? Follow the below-given steps to learn howRENAME COLUMNcommand works inPostgreSQL: Step 1: Choose a Database Open theSQL SHELLand establish a connection with a database using the“\c”command: ...
Type in it and press Enter to log into the server. List all the users with: \du This command will produce a table containing the users in the PostgreSQL server: The table returned by the "\du" command. Use \du+ to get additional information about each user, such as their description:...
Basic SELECT Query to Retrieve Tables Inside INFORMATION_SCHEMA in PostgreSQLA very simple query to get all the tables inside this SCHEMA would be to write something like this.select * from information_schema.tables This would return a table like this.Output:...
Just like in most databases, in PostgreSQL a trigger is a way to automatically respond to events. Maybe you want to run a function if data is inserted into a table. Maybe you want to audit the deletion of data, or simply respond to some UPDATE statement. That is exactly what a trigger...