What is ENUM data type in MySQL?
An ENUM is a string object with a value chosen from a list of permitted values that are enumerated explicitly in the column specification at table creation time. The ENUM type has these advantages: Compact data storage in situations where a column has a limited set of possible values.
What is the difference between the ENUM type and the set type?
An ENUM value must be one of those listed in the column definition, or the internal numeric equivalent thereof. The value cannot be the error value (that is, 0 or the empty string). A SET value must be the empty string or a value consisting only of the values listed in the column definition separated by commas.
How do you represent an ENUM and set internally in MySQL?
MySQL stores ENUM string values internally as decimal integers of values 1 through n for a column with n members in the enumeration. MySQL represents SET string values as a bitmap using one bit per value, thus the values are stored internally as 1, 2, 4, 8… up to 65,535 for a maximum of 64 members.
Is ENUM a data type?
An enum type is a special data type that enables for a variable to be a set of predefined constants. The variable must be equal to one of the values that have been predefined for it.
What is set in MySQL?
A SET is a string object that can have zero or more values, each of which must be chosen from a list of permitted values specified when the table is created. SET column values that consist of multiple set members are specified with members separated by commas ( , ).
What is enumerated data type with example?
An enumeration is a data type that consists of a set of named values that represent integral constants, known as enumeration constants. An enumeration is also referred to as an enumerated type because you must list (enumerate) each of the values in creating a name for each of them.
What does set do in MySQL?
How does enum work in MySQL?
The ENUM data type in MySQL is a string object. It allows us to limit the value chosen from a list of permitted values in the column specification at the time of table creation. It is short for enumeration, which means that each column may have one of the specified possible values.
What is the purpose of enum?
Enums are lists of constants. When you need a predefined list of values which do represent some kind of numeric or textual data, you should use an enum. You should always use enums when a variable (especially a method parameter) can only take one out of a small set of possible values.
What does SET mean in SQL?
The SET command is used with UPDATE to specify which columns and values that should be updated in a table.
What are the different data types in MySQL?
Data Types In MySQL. MySQL stores information in different formats. It allows different types of data to be used in different ways. The main types of data are character, numerical, and date and time. When you create a database, you tell MySQL what kind of data to expect in a particular column by using the MySQL names for data types.
What is data type in MySQL?
MySQL supports all standard SQL numeric data types. These types include the exact numeric data types (INTEGER, SMALLINT, DECIMAL, and NUMERIC), as well as the approximate numeric data types (FLOAT, REAL, and DOUBLE PRECISION).
What type of database is MySQL?
MySQL is a relational database management system which is an open source database.
Does an enum in MySQL need to be not null?
MySQL allows us to define the ENUM data type with the following three attributes – If we don’t want NULL values, it is required to use the NOT NULL property in the ENUM column. It is a synonym for DEFAULT NULL, and its index value is always NULL. By default, the ENUM data type is NULL, if the user doesn’t want to pass any value to it.