In order to connect to a PostgreSQL database, you must have a PostgreSQL user. A user in PostgreSQL has a username and a password to connect to the PostgreSQL server. Additionally, you can grant him various permissions to carry out his work. It is also possible to form a user …
PostgreSQL provides various date and time functions. One of the common functions is CURRENT_TIMESTAMP. PostgreSQL provides the CURRENT_TIMSTAMP function to show the current timestamp. The timestamp includes both the date and time information, along with time zone information. We can use the CURRENT_TIMSTAMP function in select queries and insert or …
PostgreSQL is an open-source relational database system. One of the common tasks of a PostgreSQL developer is to show all tables from a database. PostgreSQL provides two ways to list all tables from a database. PSQL Command Line Method PSQL allows us to interact through a terminal-based front-end. To list …
A column can be removed from PostgreSQL once it has been created. The ALTER TABLE command can be used to delete a column. You must specify both the name of the table and the desired column alongside the alter table command to delete a column in PostgreSQL. Syntax The syntax …
PostgreSQL offers a range of data types. Use ALTER TABLE command to alter column type to a different data type. The ALTER TABLE command syntax. Alter Column Type Example (Change Type Integer to VARCHAR) For example, we have the “item_type” column, which is of the integer data type. In this …
A table is made up of rows and columns. After a table is created in a database, the first action a SQL developer takes is to insert data into it to create a new row. One row of data is inserted at a time. To insert data into the PostgreSQL …
One unique feature of PostgreSQL is the ability to insert multiple rows at once with a single command. To insert multiple rows, you need to specify column names and provide a list of rows with comma-separated values in the INSERT INTO command. If a table has an auto-increment field, you …
Epoch time is an industry standard and is used in various API’s and applications. The epoch time is the number of seconds that have passed since January 1, 1970, at 00:00:00 UTC. Epoch time is consistent across various computer systems and is not affected by time zone differences. It only …
PostgreSQL provides a timestamp data type to store date and time data in a table. The PostgreSQL Extract function is used for extracting various date and time fields from timestamp data. You can extract day, month, year, and time information from a timestamp field. The extract function only returns the …
PostgreSQL is the most advanced open-source database. PostgreSQL supports many data types, and one of the special data types is bigserial data. The bigserial data type is used for creating auto-increment columns. PostgreSQL supports three data types for creating auto-increment columns. All three datatypes are used for auto-increment fields. All three …