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Codelaby
Asked: 2020-06-09 14:27:10 +0800 CST 2020-06-09 14:27:10 +0800 CST

How to modify a BD Realm record in Android?

  • 772

I can't find a way to do an update using Realm in Android Java .

Adding data and deleting no problem, I only have problems modifying existing data, it always jumps out to me that it primary keyalready exists and cannot be overwritten, but it is obvious that I assign it the same id in order to overlap the changes.

My RealmInfoDB object is a realm table

import io.realm.RealmObject;
import io.realm.annotations.PrimaryKey;

public class RealmInfoDB extends RealmObject {

    @PrimaryKey
    private long id;

    private long lastUpdate;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public long getLastUpdate() {
        return lastUpdate;
    }

    public void setLastUpdate(long lastUpdate) {
        if (lastUpdate == 0) lastUpdate = System.currentTimeMillis();
        this.lastUpdate = lastUpdate;
    }

}

To add a new record

realm.beginTransaction();
    RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
    infoDB.setId(0);
    infoDB.setLastUpdate(0);
realm.commitTransaction();

To modify I use the same and that is when I get the error

realm.beginTransaction();
    RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
    infoDB.setId(0);
    infoDB.setLastUpdate(0);
realm.commitTransaction();

Mistake

io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 0

integer error log

06-09 00:24:01.909 E/AndroidRuntime: FATAL EXCEPTION: main
   Process: realm.test.app.testrealm, PID: 1177
   java.lang.RuntimeException: Unable to start activity ComponentInfo{realm.test.app.testrealm/realm.test.app.testrealm.MainActivity}: io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 0
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4032)
       at android.app.ActivityThread.access$900(ActivityThread.java:155)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:135)
       at android.app.ActivityThread.main(ActivityThread.java:5343)
       at java.lang.reflect.Method.invoke(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700)
    Caused by: io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 0
       at io.realm.internal.Table.throwDuplicatePrimaryKeyException(Table.java:684)
       at io.realm.internal.Table.addEmptyRow(Table.java:371)
       at io.realm.Realm.createObject(Realm.java:696)
       at realm.test.app.testrealm.MainActivity.onCreate(MainActivity.java:41)
       at android.app.Activity.performCreate(Activity.java:6010)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1129)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413) 
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4032) 
       at android.app.ActivityThread.access$900(ActivityThread.java:155) 
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323) 
       at android.os.Handler.dispatchMessage(Handler.java:102) 
       at android.os.Looper.loop(Looper.java:135) 
       at android.app.ActivityThread.main(ActivityThread.java:5343) 
       at java.lang.reflect.Method.invoke(Native Method) 
       at java.lang.reflect.Method.invoke(Method.java:372) 
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700) 
java

2 Answers

  1. Best Answer

    @Webserveis id is defined as primary key, updating this field would not be possible:

    realm.beginTransaction();
    RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
    infoDB.setId(0);
    infoDB.setLastUpdate(0);
realm.commitTransaction();

    Try this way where it would only update lastUpdate:

        RealmInfoDB myObj;
    RealmInfoDB updateObj = realm.where(RealmInfoDB.class)
                            .equalTo("0", myObj.getId()).findFirst();
realm.beginTransaction();     
 updateObj.setLastUpdate(myObj.getLastUpdate());
    • 2

  2. The error is that you are generating 2 inserts with the same ID.. you should do this

    realm.beginTransaction();
RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
infoDB.setId(0);
infoDB.setLastUpdate(0);
realm.copyToRealmOrUpdate(infoDB );//nada más te faltó agregar esto, insertar o actualizar registro
realm.commitTransaction();

    On the other hand, I note that in the first query it would be necessary to addcopyToRealm(infoDB);

    realm.beginTransaction();
RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
infoDB.setId(0);
infoDB.setLastUpdate(0);
realm.copyToRealm(infoDB); //instrucción para asegurar inserción
realm.commitTransaction();

    Well, an error should have appeared here if you hadn't added copyToRealmit, I don't know why you didn't get an error, but well...

    • 1