Database functions

It is possible to set the default value when creating or altering a column. To just set a value you can use the following fluent syntax:

Create.Table("TestTable").WithColumn("Name").AsString().Nullable().WithDefaultValue("test");

In addition, in the event you want to pass in arbitrary SQL to the WithDefaultValue method, you can do so using [raw sql](xref:raw-sql.md]:

Create.Table("TestTable").WithColumn("Name").AsString().Nullable().WithDefaultValue(RawSql.Insert("SYSUTCDATETIME()"));

However, you can take advantage of some database functions to set the default value. The SystemMethods enum contains five database functions:

Function	Description
NewGuid	Creates a new GUID
NewSequentialId	Creates a new sequential GUID
CurrentDateTime	The current (local) timestamp
CurrentDateTimeOffset	The current (local) timestamp with time zone
CurrentUTCDateTime	The current (UTC) timestamp
CurrentUser	The current user name

These are specific to each database, for example CurrentDateTime calls the GETDATE() function for Sql Server and the now() function for Postgres. By using WithDefault instead of WithDefaultValue, you can pass in one of the enum values.

Create.Table("TestTable").WithColumn("Created").AsDateTime().Nullable().WithDefault(SystemMethods.CurrentDateTime);

Function/Database support matrix

Server	NewGuid	NewSequentialId	CurrentDateTime	CurrentDateTimeOffset	CurrentUTCDateTime	CurrentUser
DB2	☐	☐	☑	☐	☑	☑
Firebird	☑	☑ 1	☑	☐	☐	☐
Hana	☐	☐	☑	☐	☑	☐
JET	☐	☐	☐	☐	☐	☐
MySQL	☑	☑ 1	☑	☐	☑	☑
Oracle	☑	☑ 1	☑	☑	☑	☑
Postgres	☑ 2	☑ 2	☑	☐	☑	☑
Redshift	☐	☐	☑	☑ 3	☑	☑
SQLite	☐	☐	☑	☐	☑	☐
SQL Anywhere	☑	☑ 1	☑	☑ 3	☑	☑
SQL Server 2000	☑	☑	☑	☑ 4	☑	☑
SQL Server 2008	☑	☑	☑	☑	☑	☑
SQL Server CE	☑	☑	☑	☑ 4	☑	☑

¹ Is the same as NewGuid
² uuid-ossp extension is required
³ Implicitly contains the offset
⁴ Same as CurrentDateTime