/// <summary>
/// SQL-92, page 274<br/>
/// Note that item 9 on page 276 specifies that if ON DELETE clause is omitted, DB should act as if "NO ACTION" is implicitly stated<br/>
/// Also, Oracle violates SQL-92 by not supporting explicit ON DELETE NO ACTION clause
/// </summary>
private string _DeleteRule(ForeignKeyConstraint.ReferentialAction onDelete)
{
if (onDelete == ForeignKeyConstraint.ReferentialAction.NoAction)
{
return("");
}
return(string.Format(
"ON DELETE {0}",
_ReferentialAction(onDelete)
));
}
private static string GetStringRepresentation(ForeignKeyConstraint.ReferentialAction action)
{
switch (action)
{
case ForeignKeyConstraint.ReferentialAction.NoAction:
return("NO ACTION");
case ForeignKeyConstraint.ReferentialAction.Cascade:
return("CASCADE");
case ForeignKeyConstraint.ReferentialAction.SetNull:
return("SET NULL");
case ForeignKeyConstraint.ReferentialAction.SetDefault:
return("SET DEFAULT");
default:
throw new ApplicationException("Unknown referential action");
}
}
private static string GetStringRepresentation(ForeignKeyConstraint.ReferentialAction action)
{
switch (action)
{
case ForeignKeyConstraint.ReferentialAction.NoAction:
return("a");
case ForeignKeyConstraint.ReferentialAction.Cascade:
return("c");
case ForeignKeyConstraint.ReferentialAction.SetNull:
return("n");
case ForeignKeyConstraint.ReferentialAction.SetDefault:
return("d");
case ForeignKeyConstraint.ReferentialAction.Restrict:
return("r");
default:
throw new ApplicationException("Unknown referential action");
}
}
/// <summary>
/// SQL-92, page 274
/// SQL:1999 added a support for ON DELETE RESTRICT, and both Postgres and Oracle support it in their current versions
/// </summary>
private static string _ReferentialAction(ForeignKeyConstraint.ReferentialAction action)
{
switch (action)
{
case ForeignKeyConstraint.ReferentialAction.NoAction:
return("NO ACTION");
case ForeignKeyConstraint.ReferentialAction.Cascade:
return("CASCADE");
case ForeignKeyConstraint.ReferentialAction.SetNull:
return("SET NULL");
case ForeignKeyConstraint.ReferentialAction.SetDefault:
return("SET DEFAULT");
case ForeignKeyConstraint.ReferentialAction.Restrict:
return("RESTRICT");
default:
throw new ApplicationException(string.Format("Unknown action {0}", action));
}
}
