PostgreSQL 8.1 and above defined the fuction lastval() that returns the value of the last sequence that nextval() was used on in the current session. Call lastval() if nextval() has not yet been called in the current session throw an exception.

public override string IdentitySelectString { get; }

Public Overrides ReadOnly Property IdentitySelectString As String
	Get

public:
virtual property String^ IdentitySelectString {
	String^ get () override;
}