How to: Define Data Fields in a LightSwitch Database

You can add fields to an entity or a table in the LightSwitch database and modify the appearance and behavior of these fields.

This topic contains the following sections:

link to video For a related video demonstration, see How Do I: Format Data on a Screen in a LightSwitch Application?.

You can add fields to a table. In an entity that's generated from an external data source, you can add computed fields only.

See How to: Add a Computed Field in a LightSwitch Database.

To add a data field

  1. In Solution Explorer, open the shortcut menu for an entity or table, and then choose Open.

    Note Note

    For applications that have been upgraded to Visual Studio 2012 Update 2, on the Perspective bar, choose the Server tab.

    The entity or table opens in the Data Designer.

  2. In the Name column, enter a name for the field.

  3. In Type column, choose a data type for the new field. The following table describes each type.

    Type

    Visual Basic Type

    C# Type

    Range

    Remarks

    Binary

    Byte()

    byte[]

    -128 to 127.

    An array of bytes that has a variable length.

    Boolean

    Boolean

    bool

    True or false.

    Date

    DateTime

    DateTime

    A DateTime that's treated as a date only.

    DateTime

    DateTime

    DateTime

    12:00:00 AM, Jan 1, 0001 through 11:59:59 PM, Dec 31, 9999.

    DateTimeOffset

    DateTime

    DateTime

    A value that represents a date and time in Coordinated Universal Time (UTC) format.

    Decimal

    Decimal

    decimal

    ±1.0 × 10<sup>−28</sup> to ±7.9 × 10<sup>28</sup>.

    A fixed decimal point with 28-29 significant digits; good for accounting numbers.

    Double

    Double

    double

    ±5.0e−324 to ±1.7e308.

    A floating decimal point with 15-16 digits precision; good for scientific numbers.

    Email Address

    String

    string

    A string that's treated as an email address.

    Guid

    String

    string

    A string that's formatted as a globally unique identifier (GUID). The value is automatically generated for each record.

    Image

    Byte()

    Byte[]

    A binary that's treated as an image.

    Short Integer

    Short

    short

    -32,768 to 32,767.

    A signed 16-bit integer.

    Integer

    Integer

    int

    -2147483647 to 2147483647.

    A signed 32-bit integer.

    Long Integer

    Long

    long

    -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

    A signed 64-bit integer.

    Money

    Decimal

    decimal

    A decimal that's treated as a monetary value.

    Percent

    Decimal

    decimal

    A decimal that's treated as a percentage.

    Person

    String

    String

    A string that’s treated as a user identity.

    Phone Number

    String

    string

    A string that's treated as a phone number.

    String

    String

    string

    A sequence of zero or more Unicode characters that has a variable length.

    Web Address

    String

    string

    A string that's treated as a web address (URL).

  4. If you want to require users to provide a value for this field, select the Required check box.

You can modify a field by editing its properties in the Properties window.

If the entity was generated from an external data source, you won't be able to edit some field properties because they reflect configuration settings of the data source.

You can't override those settings by changing field properties. You must make changes to these fields on the server and then import those changes into LightSwitch by refreshing the data source.

To modify a field

  1. In the Data Designer, choose the field that you want to modify.

  2. In the Properties window, set property values.

    See Reference: Data Designer Properties.

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