Enum Generation from Table Data

The generator can create C# enumerations by reading data from database tables. There are two approaches: manual configuration and the AddEnum callback.

1. Manual Configuration (Settings.Enumerations)

Define enumerations directly in Database.tt by specifying which database table to read from.

Basic Example

Given a database table EnumTest.DaysOfWeek:

TypeName	TypeId
Sun	0
Mon	1
Tue	2
Wed	3
Thu	4
Fri	5
Sat	6

Configuration:

Settings.Enumerations = new List<EnumerationSettings>
{
    new EnumerationSettings
    {
        Name       = "DaysOfWeek",          // Name of the generated enum
        Table      = "EnumTest.DaysOfWeek", // Schema.TableName
        NameField  = "TypeName",            // Column for enum member names
        ValueField = "TypeId"               // Column for enum member values
    }
};

Generated code:

public enum DaysOfWeek
{
    Sun = 0,
    Mon = 1,
    Tue = 2,
    Wed = 3,
    Thu = 4,
    Fri = 5,
    Sat = 6
}

Hex Values Example

Given a table car_options:

enum_name	value
SunRoof	1
Spoiler	2
FogLights	4
TintedWindows	8

Configuration:

new EnumerationSettings
{
    Name       = "CarOptions",
    Table      = "car_options",
    NameField  = "enum_name",
    ValueField = "value"
}

Generated code:

public enum CarOptions
{
    SunRoof       = 0x01,
    Spoiler       = 0x02,
    FogLights     = 0x04,
    TintedWindows = 0x08
}

Adding [Description] Attributes

Option A: Description from a database column

new EnumerationSettings
{
    Name             = "DaysOfWeek",
    Table            = "EnumTest.DaysOfWeek",
    NameField        = "TypeName",
    ValueField       = "TypeId",
    DescriptionField = "Description"  // Column containing the description text
}

Generated code:

public enum DaysOfWeek
{
    [Description("Sunday")]    Sun = 0,
    [Description("Monday")]    Mon = 1,
    [Description("Tuesday")]   Tue = 2,
    // ...
}

Option B: Generate description automatically from the enum member name

new EnumerationSettings
{
    Name                        = "CarOptions",
    Table                       = "car_options",
    NameField                   = "enum_name",
    ValueField                  = "value",
    GenerateDescriptionFromName = true   // Converts "SunRoof" -> "Sun roof"
}

Generated code:

public enum CarOptions
{
    [Description("Sun roof")]      SunRoof       = 0x01,
    [Description("Spoiler")]       Spoiler       = 0x02,
    [Description("Fog lights")]    FogLights     = 0x04,
    [Description("Tinted windows")] TintedWindows = 0x08
}

Both options combined: If DescriptionField is set but a row has a null/empty description, and GenerateDescriptionFromName = true, the generated name is used as a fallback.

Grouping Multiple Enums from a Single Table (GroupField)

If a single database table contains multiple enumerations differentiated by a group column, use GroupField:

GroupName	MemberName	MemberValue
Color	Red	1
Color	Green	2
Color	Blue	3
Size	Small	1
Size	Medium	2
Size	Large	3

Configuration:

new EnumerationSettings
{
    Name       = "{GroupField}Enum",  // {GroupField} is replaced with the group value
    Table      = "dbo.EnumValues",
    NameField  = "MemberName",
    ValueField = "MemberValue",
    GroupField = "GroupName"          // Column that identifies the enum group
}

Generated code:

public enum ColorEnum  { Red = 1, Green = 2, Blue = 3 }
public enum SizeEnum   { Small = 1, Medium = 2, Large = 3 }

EnumerationSettings Properties Summary

Property	Type	Required	Description
Name	string	Yes	Name of the generated enum. Use {GroupField} placeholder if grouping.
Table	string	Yes	Database table in Schema.TableName format.
NameField	string	Yes	Column containing enum member names.
ValueField	string	Yes	Column containing enum member values.
GroupField	string	No	Column for grouping multiple enums in one table.
DescriptionField	string	No	Column containing [Description] text.
GenerateDescriptionFromName	bool	No	If true, auto-generates [Description] from the member name when no description is available.

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2. Programmatic Approach (Settings.AddEnum Callback)

The AddEnum callback is invoked for each table during reverse engineering. Use it to programmatically decide which tables should become enums — for example, tables matching a naming convention.

Requires Settings.ElementsToGenerate to include both Elements.Poco and Elements.Enum.

Settings.AddEnum = delegate (Table table)
{
    if (table.HasPrimaryKey &&
        table.PrimaryKeys.Count() == 1 &&
        table.Columns.Any(x => x.PropertyType == "string"))
    {
        // Convert tables named "XxxEnum" or "EnumXxx" into enumerations
        if (table.NameHumanCase.StartsWith("Enum", StringComparison.InvariantCultureIgnoreCase) ||
            table.NameHumanCase.EndsWith  ("Enum", StringComparison.InvariantCultureIgnoreCase))
        {
            try
            {
                Settings.Enumerations.Add(new EnumerationSettings
                {
                    Name       = table.NameHumanCase.Replace("Enum", "") + "Enum",
                    Table      = table.Schema.DbName + "." + table.DbName,
                    NameField  = table.Columns.First(x => x.PropertyType == "string").DbName,
                    ValueField = table.PrimaryKeys.Single().DbName,
                    GroupField = string.Empty
                });

                // Stop the table from being added to the DbContext
                table.RemoveTable = true;
            }
            catch { }
        }
    }
};

Remove table.RemoveTable = true; if you want to keep the table as a POCO in addition to generating the enum.