SQLServer IDENTITY Column with text
In addition to the other answers, you could create a computed column on the table to provide what you are asking for.
CREATE TABLE dbo.MyTable
(
Id int NOT NULL PRIMARY KEY,
CombinedId AS 'ABCD-' + CAST(Id as varchar(16))
)
Or:
CREATE TABLE dbo.MyTable
(
Id int NOT NULL PRIMARY KEY,
PrefixField varchar(16),
CombinedId AS PrefixField + CAST(Id as varchar(16))
)
(Your question doesn't say whether the prefix is intended to be fixed or not...)
You'd have to not use an IDENTITY column, but generated the ids/strings yourself.
Far better to format the IDENTITY column for display instead, especially if the string part is constant for all records - makes indexing/querying more performance and saves on db space.
If records may have a different string section (i.e. not all starting with "ABCD-"), then you could store that as a separate field.