Android Room defaultValue="CURRENT_TIMESTAMP" does not work

Question

I am trying to implement schema default values which came with Room 2.2 to my entity but it does not seem to work.

I have an entity called Place:

@Entity
public class Place implements Parcelable {

    @PrimaryKey(autoGenerate = true)
    private Long placeId;

    private String name;

    private double latitude;

    private double longitude;

    private int radius;

    @ColumnInfo(defaultValue = "CURRENT_TIMESTAMP")
    private String createdAt;

    @Ignore
    public Place() {}

    public Place(String name, double latitude, double longitude, int radius) {
        this.name = name;
        this.latitude = latitude;
        this.longitude = longitude;
        this.radius = radius;
    }

    // getters and setters...

    public String getCreatedAt() {
        return createdAt;
    }

    public void setCreatedAt(String createdAt) {
        this.createdAt = createdAt;
    }

}

When a place is inserted into the database, createdAt field is always getting inserted as NULL.

Changing createdAt variable into long replaces fields with 0.

What am I doing wrong here?

What makes you think that it should work? There is no mention of `@ColumnInfo(defaultValue = "CURRENT_TIMESTAMP")` in the official documentation of Room. — Sergey Emeliyanov, Dec 15 '19 at 01:10
see [how to automatically set timestamp in room sqlite database](https://stackoverflow.com/questions/59323938/how-to-automatically-set-timestamp-in-room-sqlite-database/59326573) — MikeT, Dec 15 '19 at 01:10
@SerjArdovic see [defaultValue](https://developer.android.com/reference/androidx/room/ColumnInfo.html#defaultValue()) — MikeT, Dec 15 '19 at 01:12
I watched [this](https://youtu.be/_aJsh6P00c0?t=713), did I get it wrong? — Mertcan Seğmen, Dec 15 '19 at 01:17
@MikeT, it's virtually a duplicate question, basically the answer suggests that `@Insert()` doesn't work, yet more specific `@Query("INSERT INTO test_table001 (name) VALUES(:name) ")` does work.. interesting — Sergey Emeliyanov, Dec 15 '19 at 01:17
@MertcanSeğmen, seeing that it's quite new feature, might be experimental.. again consider updating your dependencies (Room, androidx..) to the most recent versions, might help. — Sergey Emeliyanov, Dec 15 '19 at 01:21

score 5 · Accepted Answer · answered Dec 15 '19 at 05:39

You can use @Query with specfific column names (and values), excluding those to be defaulted to.

As per :-

Note that the default value you specify here will NOT be used if you simply insert the Entity with @Insert. In that case, any value assigned in Java/Kotlin will be used. Use @Query with an INSERT statement and skip this column there in order to use this default value. defaultValue

So in this case you can use :-

@Query("INSERT INTO Place (name,latitude,longitude,radius) VALUES(:name,:latitude,:logitude,:radius)")

The reason is that with the exception of an alias of the rowid. If null is passed where a column name has been specified either explicitly or implicitly then the default value is not used so the value store is null.

consider :-

DROP TABLE IF EXISTS place;
CREATE TABLE IF NOT EXISTS `Place` (`placeId` INTEGER PRIMARY KEY AUTOINCREMENT, `name` TEXT, `latitude` REAL NOT NULL, `longitude` REAL NOT NULL, `radius` INTEGER NOT NULL, `createdAt` TEXT DEFAULT CURRENT_TIMESTAMP);

INSERT INTO place VALUES(null,'opt1',0,0,0,null); //<<<< As per @Insert
INSERT INTO place (name,latitude,longitude,radius) VALUES('opt2',1,1,1); //<<<< As per @Query
SELECT * FROM place;

The results in :-

Room actually builds the following 2 queries (as per the generated code)

"INSERT OR ABORT INTO `Place` (`placeId`,`name`,`latitude`,`longitude`,`radius`,`createdAt`) VALUES (?,?,?,?,?,?)"

and

"INSERT INTO place (name,latitude,longitude,radius) VALUES(?, ?, ?, ?)"

What could be then If the value of one field needs to be inserted as the default value unless it is set? Suppose, -1 as the default value is inserted if not set earlier. Then in some cases, the value could be specified where it will insert the default value. — Patriotic, May 31 '20 at 01:01
In this case, I have solved this by simply putting a default value in the member variable and then update it via setter if required. — Patriotic, May 31 '20 at 01:13

Android Room defaultValue="CURRENT_TIMESTAMP" does not work

1 Answers1