MapInfo

Added in 2.4.0
Deprecated in 2.6.0
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    @Target(allowedTargets = [AnnotationTarget.FUNCTION])
    @Retention(value = AnnotationRetention.BINARY)
    annotation MapInfo

Declares which column(s) are used to build a map or multimap return value in a Dao query method.

This annotation is required when the key or value of the Map is a single column of one of the built in types (primitives, boxed primitives, enum, String, byte[], ByteBuffer) or a type with a converter (e.g. Date, UUID, etc).

The use of this annotation provides clarity on which column should be used in retrieving information required by the return type.

Example:

@MapInfo(keyColumn = "artistName", valueColumn = "songName")
@Query("SELECT * FROM Artist JOIN Song ON Artist.artistName = Song.artist")
fun getArtistNameToSongNames(): Map<String, List<String>>

@MapInfo(valueColumn = "songCount")
@Query("SELECT *, COUNT(mSongId) as songCount FROM Artist JOIN Song ON
Artist.artistName = Song.artist GROUP BY artistName")
fun getArtistAndSongCounts(): Map<Artist, Integer>

To use the @MapInfo annotation, you must provide either the key column name, value column name, or both, based on the Dao's method return type. Column(s) specified in the provided @MapInfo annotation must be present in the query result.

Summary

Public constructors
MapInfo(
    keyColumn: String,
    keyTable: String,
    valueColumn: String,
    valueTable: String
)
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Public properties
String

The name of the column to be used for the map's keys.
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String

The name of the table or alias to be used for the map's keys.
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String

The name of the column to be used for the map's values.
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String

The name of the table or alias to be used for the map's values.
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Public constructors

MapInfo

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MapInfo(
    keyColumn: String = "",
    keyTable: String = "",
    valueColumn: String = "",
    valueTable: String = ""
)

Public properties

keyColumn

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val keyColumn: String

The name of the column to be used for the map's keys.

Returns
String

The key column name.

keyTable

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val keyTable: String

The name of the table or alias to be used for the map's keys.

Providing this value is optional. Useful for disambiguating between duplicate column names. For example, consider the following query: SELECT * FROM Artist AS a JOIN Song AS s ON a.id == s.artistId, then the @MapInfo for a return type Map<String, List<Song>> would be @MapInfo(keyColumn = "id", keyTable ="a").

Returns
String

The key table name.

valueColumn

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val valueColumn: String

The name of the column to be used for the map's values.

Returns
String

The value column name.

valueTable

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val valueTable: String

The name of the table or alias to be used for the map's values.

Providing this value is optional. Useful for disambiguating between duplicate column names. For example, consider the following query: SELECT * FROM Song AS s JOIN Artist AS a ON s.artistId == a.id, then the @MapInfo for a return type Map<Song, String> would be @MapInfo(valueColumn = "id", valueTable ="a").

Returns
String

The key table name.