/// <summary>
/// Column should have unique values. Only one row with null value should be accepted (default for most known database engines).
/// </summary>
/// <param name="expression">The expression to set this option for</param>
/// <param name="nullsAreDistinct"><c>true</c> when nulls should be distinct</param>
/// <returns>The <paramref name="expression"/></returns>
public static ICreateIndexOnColumnSyntax NullsDistinct(
this ICreateIndexMoreColumnOptionsSyntax expression,
bool nullsAreDistinct = true)
{
expression.CurrentColumn.AdditionalFeatures[IndexColumnNullsDistinct] = nullsAreDistinct;
return(expression);
}
/// <summary>
/// Specifies that nulls sort before non-nulls.
/// </summary>
/// <param name="expression">The <see cref="ICreateIndexMoreColumnOptionsSyntax"/></param>
/// <param name="sort">The <see cref="NullsSort"/>.</param>
/// <returns>The <see cref="ICreateIndexMoreColumnOptionsSyntax"/></returns>
public static ICreateIndexMoreColumnOptionsSyntax Nulls(this ICreateIndexMoreColumnOptionsSyntax expression, NullSort sort)
{
var additionalFeatures = expression as ISupportAdditionalFeatures;
additionalFeatures.Nulls(sort);
return(expression);
}
/// <summary>
/// Specifies that nulls sort after non-nulls. This is the default when DESC is not specified.
/// </summary>
/// <param name="expression">The <see cref="ICreateIndexMoreColumnOptionsSyntax"/></param>
/// <returns>The <see cref="ICreateIndexMoreColumnOptionsSyntax"/></returns>
public static ICreateIndexMoreColumnOptionsSyntax NullsLast(this ICreateIndexMoreColumnOptionsSyntax expression)
{
var additionalFeatures = expression.CurrentColumn as ISupportAdditionalFeatures;
additionalFeatures.Nulls(NullSort.Last);
return(expression);
}
/// <summary>
/// Column should have unique values, but multiple rows with null values should be accepted.
/// </summary>
/// <param name="expression">The expression to set this option for</param>
/// <returns>The <paramref name="expression"/></returns>
public static ICreateIndexOnColumnSyntax NullsNotDistinct(
this ICreateIndexMoreColumnOptionsSyntax expression)
{
return(NullsDistinct(expression, false));
}
