UPD. last time I had this annoying issue Invalidate cache/Restart fixed this for me. Sigh Running the app in Debug mode (Win: Shift+F9 or Mac: Control+D) does the magic for me sometimes. Not sure if this is a bug or not. The android documentation doesn’t mention on this, so I guess it should just work … Read more
Use CASE Expression for SQLite to achieve this in Room DAO, @Query(“SELECT * FROM Persons ORDER BY CASE WHEN :isAsc = 1 THEN first_name END ASC, CASE WHEN :isAsc = 0 THEN first_name END DESC”) List<Person> getPersonsAlphabetically(boolean isAsc);
With the release of room persistence 2.2.0, there’s a new property added to @ColumnInfo annotation which can be used to specify the default value of a column. See documentation. @Entity(tableName = “users”) data class User( @PrimaryKey val id: Long, @ColumnInfo(name = “user_name”, defaultValue = “temp”) val name: String @ColumnInfo(name = “last_modified”, defaultValue = “CURRENT_TIMESTAMP” ) … Read more
Room is an ORM, Object Relational Mapping library. In other words, Room will map our database objects to Java objects. Room provides an abstraction layer over SQLite to allow fluent database access while harnessing the full power of SQLite. Difference between SQLite and Room persistence library:- In case of SQLite, There is no compile time … Read more
You can use RoomDatabase.runInTransaction(…) Something like: database.runInTransaction(new Runnable(){ @Override public void run(){ Access all your daos here } });
Is this the expected way to handle it? No. It is a wrong approach. You should eliminate duplication of data for several reasons. It will cost storage space. As the size of database increases, this will began to become worse. It will make the system complicated. If you are updating a single field, You may … Read more
As pointed out on documentation for Transaction, you can do following: @Dao public abstract class ProductDao { @Insert public abstract void insert(Product product); @Delete public abstract void delete(Product product); @Transaction public void insertAndDeleteInTransaction(Product newProduct, Product oldProduct) { // Anything inside this method runs in a single transaction. insert(newProduct); delete(oldProduct); } }
androidx.legacy:legacy-support-v4 is Androidx artifacts of com.android.support:support-v4 com.android.support:support-v13 -> androidx.legacy:legacy-support-v13 com.android.support:support-v4 -> androidx.legacy:legacy-support-v4 You can find info about the library mapping here The Support Library is a static library that you can add to your Android application in order to use APIs that are either not available for older platform versions or utility APIs that aren’t … Read more
@Ignore is a Room-specific annotation, saying that Room should ignore that field or method. transient is a Java construct, indicating that this field should not be serialized in standard Java serialization. Room happens to treat this similarly to @Ignore by default. Mostly, that is there for cases where you are inheriting from some class that … Read more
What is happening The only values you can pass as paramters to @Dao methods are values, not query strings. The reason for this (I beleive) is to prevent SQL injection issues. Why this is the case For example the query SELECT * emails WHERE uid = ? then setting the value as “1 OR WHERE … Read more