YapDatabaseSecondaryIndexTransaction

@interface YapDatabaseSecondaryIndexTransaction : YapDatabaseExtensionTransaction

/**
 * These methods allow you to enumerates matches from the secondary index(es) using a given query.
 *
 * The query that you input is an SQL style query (appropriate for SQLite semantics),
 * excluding the "SELECT ... FROM 'tableName'" component.
 * 
 * For example:
 * 
 * query = [YapDatabaseQuery queryWithFormat:@"WHERE age >= 62"];
 * [[transaction ext:@"idx"] enumerateKeysMatchingQuery:query usingBlock:^(NSString *key, BOOL *stop) {
 * 
 *     // ...
 * }];
 *
 * You can also pass parameters to the query using the standard SQLite placeholder:
 * 
 * query = [YapDatabaseQuery queryWithFormat:@"WHERE age >= ? AND state == ?", @(age), state];
 * [[transaction ext:@"idx"] enumerateKeysMatchingQuery:query usingBlock:^(NSString *key, BOOL *stop) {
 *
 *     // ...
 * }];
 *
 * For more information, and more examples, please see YapDatabaseQuery.
 * 
 * @return NO if there was a problem with the given query. YES otherwise.
 * 
 * @see YapDatabaseQuery
 */

- (BOOL)enumerateKeysMatchingQuery:(YapDatabaseQuery *)query
                        usingBlock:(void (NS_NOESCAPE^)(NSString *collection, NSString *key, BOOL *stop))block;

- (BOOL)enumerateKeysAndMetadataMatchingQuery:(YapDatabaseQuery *)query
                                   usingBlock:
                            (void (NS_NOESCAPE^)(NSString *collection, NSString *key, __nullable id metadata, BOOL *stop))block;

- (BOOL)enumerateKeysAndObjectsMatchingQuery:(YapDatabaseQuery *)query
                                  usingBlock:
                            (void (NS_NOESCAPE^)(NSString *collection, NSString *key, id object, BOOL *stop))block;

- (BOOL)enumerateRowsMatchingQuery:(YapDatabaseQuery *)query
                        usingBlock:
                            (void (NS_NOESCAPE^)(NSString *collection, NSString *key, id object, __nullable id metadata, BOOL *stop))block;

- (BOOL)enumerateIndexedValuesInColumn:(NSString *)column matchingQuery:(YapDatabaseQuery *)query usingBlock:(void(NS_NOESCAPE^)(id indexedValue, BOOL *stop))block;

/**
 * Skips the enumeration process, and just gives you the count of matching rows.
 */
- (BOOL)getNumberOfRows:(NSUInteger *)count matchingQuery:(YapDatabaseQuery *)query;

/**
 * Aggregate Queries.
 * 
 * E.g.: avg, max, min, sum
 * 
 * For more inforation, see the sqlite docs on "Aggregate Functions":
 * https://www.sqlite.org/lang_aggfunc.html
 */
- (nullable id)performAggregateQuery:(YapDatabaseQuery *)query;

/**
 * This method assists in performing a query over a subset of rows,
 * where the subset is a known set of keys.
 * 
 * For example:
 * 
 * Say you have a bunch of tracks & playlist objects in the database.
 * And you've added a secondary index on track.duration.
 * Now you want to quickly figure out the duration of an entire playlist.
 * 
 * NSArray *keys = [self trackKeysInPlaylist:playlist];
 * NSArray *rowids = [[[transaction ext:@"idx"] rowidsForKeys:keys inCollection:@"tracks"] allValues];
 *
 * YapDatabaseQuery *query =
 *   [YapDatabaseQuery queryWithAggregateFunction:@"SUM(duration)" format:@"WHERE rowid IN (?)", rowids];
 */
- (NSDictionary<NSString*, NSNumber*> *)rowidsForKeys:(NSArray<NSString *> *)keys
                                         inCollection:(nullable NSString *)collection;

@end

Undocumented

  • These methods allow you to enumerates matches from the secondary index(es) using a given query.

    The query that you input is an SQL style query (appropriate for SQLite semantics), excluding the SELECT … FROM ‘tableName’ component.

    For example:

    query = [YapDatabaseQuery queryWithFormat:@WHERE age >= 62]; [[transaction ext:@idx] enumerateKeysMatchingQuery:query usingBlock:^(NSString *key, BOOL *stop) {

     // ...

    }];

    You can also pass parameters to the query using the standard SQLite placeholder:

    query = [YapDatabaseQuery queryWithFormat:@WHERE age >= ? AND state == ?, @(age), state]; [[transaction ext:@idx] enumerateKeysMatchingQuery:query usingBlock:^(NSString *key, BOOL *stop) {

     // ...

    }];

    For more information, and more examples, please see YapDatabaseQuery.

    See

    YapDatabaseQuery

    Declaration

    Objective-C

    - (BOOL)enumerateKeysMatchingQuery:(nonnull YapDatabaseQuery *)query
                        usingBlock:(nonnull void (^)(NSString *_Nonnull,
                                                     NSString *_Nonnull,
                                                     BOOL *_Nonnull))block;

    Swift

    func enumerateKeys(matching query: YapDatabaseQuery, using block: (String, String, UnsafeMutablePointer<ObjCBool>) -> Void) -> Bool

    Return Value

    NO if there was a problem with the given query. YES otherwise.

  • Undocumented

    Declaration

    Objective-C

    - (BOOL)enumerateKeysAndMetadataMatchingQuery:(YapDatabaseQuery *)query
                                   usingBlock:
                            (void (NS_NOESCAPE^)(NSString *collection, NSString *key, __nullable id metadata, BOOL *stop))block;

    Swift

    func enumerateKeysAndMetadata(matching query: YapDatabaseQuery, using block: (String, String, Any?, UnsafeMutablePointer<ObjCBool>) -> Void) -> Bool

  • Undocumented

    Declaration

    Objective-C

    - (BOOL)enumerateKeysAndObjectsMatchingQuery:(YapDatabaseQuery *)query
                                  usingBlock:
                            (void (NS_NOESCAPE^)(NSString *collection, NSString *key, id object, BOOL *stop))block;

    Swift

    func enumerateKeysAndObjects(matching query: YapDatabaseQuery, using block: (String, String, Any, UnsafeMutablePointer<ObjCBool>) -> Void) -> Bool

  • Undocumented

    Declaration

    Objective-C

    - (BOOL)enumerateRowsMatchingQuery:(YapDatabaseQuery *)query
                        usingBlock:
                            (void (NS_NOESCAPE^)(NSString *collection, NSString *key, id object, __nullable id metadata, BOOL *stop))block;

    Swift

    func enumerateRows(matching query: YapDatabaseQuery, using block: (String, String, Any, Any?, UnsafeMutablePointer<ObjCBool>) -> Void) -> Bool

  • Undocumented

    Declaration

    Objective-C

    - (BOOL)enumerateIndexedValuesInColumn:(NSString *)column matchingQuery:(YapDatabaseQuery *)query usingBlock:(void(NS_NOESCAPE^)(id indexedValue, BOOL *stop))block;

    Swift

    func enumerateIndexedValues(inColumn column: String, matching query: YapDatabaseQuery, using block: (Any, UnsafeMutablePointer<ObjCBool>) -> Void) -> Bool

  • Skips the enumeration process, and just gives you the count of matching rows.

    Declaration

    Objective-C

    - (BOOL)getNumberOfRows:(nonnull NSUInteger *)count
          matchingQuery:(nonnull YapDatabaseQuery *)query;

    Swift

    func getNumberOfRows(_ count: UnsafeMutablePointer<UInt>, matching query: YapDatabaseQuery) -> Bool

  • Aggregate Queries.

    E.g.: avg, max, min, sum

    For more inforation, see the sqlite docs on Aggregate Functions: https://www.sqlite.org/lang_aggfunc.html

    Declaration

    Objective-C

    - (nullable id)performAggregateQuery:(nonnull YapDatabaseQuery *)query;

    Swift

    func performAggregateQuery(_ query: YapDatabaseQuery) -> Any?

  • This method assists in performing a query over a subset of rows, where the subset is a known set of keys.

    For example:

    Say you have a bunch of tracks & playlist objects in the database. And you’ve added a secondary index on track.duration. Now you want to quickly figure out the duration of an entire playlist.

    NSArray *keys = [self trackKeysInPlaylist:playlist]; NSArray *rowids = [[[transaction ext:@idx] rowidsForKeys:keys inCollection:@tracks] allValues];

    YapDatabaseQuery *query = [YapDatabaseQuery queryWithAggregateFunction:@SUM(duration) format:@WHERE rowid IN (?), rowids];

    Declaration

    Objective-C

    - (nonnull NSDictionary<NSString *, NSNumber *> *)
    rowidsForKeys:(nonnull NSArray<NSString *> *)keys
     inCollection:(nullable NSString *)collection;

    Swift

    func rowids(forKeys keys: [String], inCollection collection: String?) -> [String : NSNumber]