What Is Projection Mapping?

The projection map appears in the android ContentProvider and serves as an intermediary between the abstract column set and the actual column set in the database. These column sets may be different. When constructing a query, a map must be established between the where clause columns specified by the client and the actual database columns. You can use the SQLiteQueryBuilder class to build a projection map. The projection mapping maps column names in the query passed in to the method to database column names. If a projection mapping is set, he must include all column names for all possible requests, even if the keys and values of those columns are the same

Projection mapping

Right!

The projection map appears in the android ContentProvider and serves as an intermediary between the abstract column set and the actual column set in the database. These column sets may be different. When constructing a query, a map must be established between the where clause columns specified by the client and the actual database columns. You can use the SQLiteQueryBuilder class to build a projection map. The projection mapping maps column names in the query passed in to the method to database column names. If a projection mapping is set, he must include all column names for all possible requests, even if the keys and values of those columns are the same

Chinese name

Projection mapping

Foreign name

projection map

Appeared in

android content

Acting as

Abstract column set

Borrow

SQLiteQueryBuilder

The projection map appears in the android ContentProvider and serves as an intermediary between the abstract column set and the actual column set in the database. These column sets may be different. When constructing a query, a map must be established between the where clause columns specified by the client and the actual database columns. You can use the SQLiteQueryBuilder class to build a projection map. The projection mapping maps column names in the query passed in to the method to database column names. If a projection mapping is set, he must include all column names for all possible requests, even if the keys of those columns have the same value.