8/26/2023 0 Comments Mysql create table integer columnThe course_id column store the course that employee took.The employee_id column store the id of employees who took the course.The trainings table consists of three columns: To store the training data, you create a new table named training as follows. Now you have the table to store the course data. The NOT NULL constraint ensures that there is no NULL values stored in the course_name column. Its data type is the character string ( VARCHAR) with maximum length is 50. The course_name stores the names of courses. It means that when you insert a new row into the courses table without providing the value for the course_id column, the database system will generate an integer value for the column. In addition, the value of the course_id column is AUTO_INCREMENT. The data type of the course_id is integer denoted by the INT keyword. It is a good practice to define a primary key for every table. Each table has one and only one primary key that uniquely identifies each row in the table. The course_id is the primary key column of the courses table. The courses table has two columns: course_id and course_name. The following statement creates the courses table: CREATE TABLE courses (Ĭourse_id INT AUTO_INCREMENT PRIMARY KEY, You looked at the current database and found no place to store this information, therefore, you decided to create new tables. Suppose you have to store the training data of employees in the database with a requirement that each employee may take zero or many training courses, and each training course may be taken by zero or many employees. For example, if a table has the primary key that consists of two columns, in this case, you have to use the PRIMARY KEY table constraint. In case a constraint contains multiple columns, you use the table constraint. For example, the username column of the users table can have both NOT NULL and UNIQUE constraints. For example, the NOT NULL constraint ensures that the column does not contain any NULL value.Ī column may have multiple column constraints. The column constraint controls what kind of value that can be stored in the column. The data type of the column can be the numeric, characters, date, etc. The data type of a column specifies the type of data that column can store. Each column definition is composed of a column name, column’s data type, a default value, and one or more column constraints. In the CREATE TABLE statement, you specify a comma-separated list of column definitions. If you create a table whose name is the same as the one that already exists, the database system will issue an error. The name of the table, given by the table_name, must be unique within the database. The minimum required information for creating a new table is a table name and a column name. ) Code language: SQL (Structured Query Language) ( sql ) To create a new table, you use the CREATE TABLE statement with the following syntax: CREATE TABLE table_name(Ĭolumn_name_1 data_type default value column_constraint,Ĭolumn_name_2 data_type default value column_constraint, It is time to learn how to create your own tables.Ī table is a collection of data stored in a database. So far, you have learned various ways to query data from one or more table in the sample database. Introduction to SQL CREATE TABLE statement Summary: in this tutorial, you will learn how to use the SQL CREATE TABLE statement to create new tables.
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