Source: https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/data-types/map-type/
Documentation version: v5.3.2

# Map types

A map is a constructed data type used to store an unordered collection of key-value pairs. Each key in a map is unique and associated with a specific value.

Maps are enclosed in curly braces with key-value pairs separated by commas (`,`). Each key is separated from its corresponding value by a colon (`:`).

The map type must be declared using the `MAP<key_type, value_type>` syntax, where `key_type` and `value_type` specify the data types of the keys and values, respectively. Both `key_type` and `value_type` can be any predefined data type or constructed data type other than records and paths.

## Declaration example

````
'''
CREATE GRAPH TYPE IF NOT EXISTS map_type AS {
    NODE person 
     ( {
        id INT PRIMARY KEY,
        name STRING,
        attributes MAP<STRING, BOOL> DEFAULT MAP{ 'is_student': false, 'is_employed': true}
     } )
}
'''

````

## Supported operators

The map type supports the following operators:

 | Operator | Name | Description | Example | Result
 | `||` | Union | Merges two maps into one. If both maps contain the same key, the value from the first map is retained. | `RETURN MAP{'a': 1, 'b': 2} || MAP{'b': 3, 'c': 4}` | `{a:1,b:2,c:4}`
 | `IN` | Inclusion | Checks if a specific key exists in the map. | `RETURN 'a' IN MAP{'a': 1, 'b': 2}` | `true`
 | `NOT IN` | Exclusion | Checks if a specific key does not exist in the map. | `RETURN 'c' NOT IN MAP{'a': 1, 'b': 2}` | `true`

## More information

[Map literals](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/literals/#map_literals)