Identifiers for SQL Server objects, including database and table names, must conform to certain rules.
The identifier string can consist of:
The first character cannot be a number or dollar sign ($). Use a letter for the first character.
The identifier must not be a Transact-SQL reserved word.
The identifier must not contain spaces or special characters.
NOTE: According to the Microsoft MSDN Library, "Database names must be unique within a server and conform to the rules for identifiers." Also, limit the database name to 123 characters so that the transaction log file name is less than 128 characters. If these rules are not followed, the database will not be created.