org.apache.ignite.cache.query.annotations

注釈型 QuerySqlField.Group

@Retention(value=RUNTIME)
 @Target(value={METHOD,FIELD})
public static @interface QuerySqlField.Group

Describes group of index and position of field in this group.

Opposite to QuerySqlField.groups() this annotation gives control over order of fields in a group index. This can be needed in scenarios when we have a query like select * from X where a = ? and b = ? order by b desc. If we have index (a asc, b asc) sorting on b will be performed. Here it is preferable to have index (b desc, a asc) which will still allow query to search on index using both fields and avoid sorting because index is already sorted in needed way.

関連項目:

QuerySqlField.groups(), QuerySqlField.orderedGroups()

必須要素のサマリー

必須要素

修飾子とタイプ	必須要素と説明
java.lang.String	name Group index name where this field participate.
int	order Fields in this group index will be sorted on this attribute.

任意要素のサマリー

任意要素

修飾子とタイプ	任意要素と説明
boolean	descending Defines sorting order for this field in group.

要素の詳細

name

public abstract java.lang.String name

Group index name where this field participate.

戻り値:

Group index name

order

public abstract int order

Fields in this group index will be sorted on this attribute.

戻り値:

Order number.

descending

public abstract boolean descending

Defines sorting order for this field in group.

戻り値:

True if field will be in descending order.

デフォルト:

false