CRUD operations explained: Create, read, update, and delete
- ️Wed Dec 16 2020
SQL is a standard language used to store, manipulate, and retrieve data from databases. Let’s go over a few different ways you can use CRUD SQL queries to create a database and table, insert data into tables, and perform basic operations on data within tables.
CREATE operation#
The CREATE operation lets you create a new database and its tables.
In SQL, a new database is created using the CREATE DATABASE keyword.
CREATE DATABASE db_name
Similarly, you can create a new table using the `CREATE TABLE` keyword.
CREATE TABLE table_name (col_1, col_2, ...)
You can add new records using the command INSERT INTO. This command starts with the INSERT INTO keyword, followed by the table name, column names, and the values to be inserted.
When using INSERT INTO, you have two options:
INSERT INTO table_name
VALUES (value1, value2, value3, ...);
INSERT INTO table_name (column1, column2, column3, ...)
VALUES (value1, value2, value3, ...);
In the example below, you can create a database bakery and table menu. Afterward, you can insert data into your menu table.
CREATE DATABASE bakery;
CREATE TABLE menu (id Int, item varchar(10), date DATE);
INSERT INTO menu
VALUES (1, 'croissant', '2020-12-16');
If you want to insert multiple rows, you can do that using the following syntax:
INSERT INTO menu
VALUES
(2, 'bread', '2020-12-16' ),
(3, 'eclairs', '2020-12-16' );
This will insert two new rows to the menu table, and give each entry a unique id.