# Data Extension Types



Overview [#overview]

This topic discussed the types of data that can be used with configured [data extensions](/configuration/data-extensions/overview).

<span id="built-in-types" />

Built-In Data Types [#built-in-data-types]

These data types are supported without additional configuration:

* `string`: A string, or enum-like type with a fixed set of possible values, set with the options property for the type.
* `int` : A 32-bit signed integer
* `long`: A 64-bit signed integer
* `decimal`: A floating point number with arbitrary precision, which internally uses base 10 representation and so is appropriate for financial calculations
* `datetime`: A value which includes a date and a time
* `date`: The same as `datetime` except that no time component is included.
* `boolean`: A datatype than can have either the value `true` or `false`

<Callout>
  - The type can be omitted. If so, the default type of `string` will be used.
  - Booleans can take a number `0` or `1`, which will be interpreted as `false` or `true` respectively.
</Callout>

Date Types [#date-types]

datetime [#datetime]

The `datetime` type includes a date and a time, with precision to milliseconds, and includes a time-zone context which by default will be the policy's time zone. In the API these are passed as strings using ISO8601 format, such as `"2023-07-15T12:30:00−07:00"`.

Clients may express date time values with any time zone, but they will be handled according to the time zone for the quote or policy. For example, if the time zone for a policy is `America/Los_Angeles` but a `startTime` of `2023-07-15T00:00:00Z` (which specifies UTC) then the start time of the policy will be July 15, 2023 at 8AM (which equals midnight in UTC).

<Callout>
  ISO 8601 allows for times to be expressed to milliseconds precision, such as `2023-07-15T12:30:00.444−07:00`. The milliseconds component is optional and will be interpreted as zero if it is not included.
</Callout>

date [#date]

The `date` is the same as `datetime` except that no time or time zone component is included. These are passed by a string such as `"2023-04-15"`.

Custom Data Types [#custom-data-types]

Along with built-in data types, you can use *custom* data types to manage more complicated or specialized data.

See the [Custom Data Types](/configuration/data-extensions/custom-data-types) topic for details.

Limitations [#limitations]

* `string` types are limited to a maximum of 20,000 characters.