How to attach a database in Room? - android

I tried to attach database in Android Room like this: How to select from multiple databases in Android Room(How to attach databases) but i got error when building project:
error: There is a problem with the query: [SQLITE_ERROR] SQL error or missing database (no such table: database.table)
Error concerns
#Query("select t.id as tid from mydatabase.mytable t")
public List<MyPojo> getMyTableIds();
When I added #SkipQueryVerification, error changed on: error: Not sure how to convert a Cursor to this method's return type.
Error dissapears when I remove "mydatabase." from Query.
How to attach database in Android Room and make cross databases query?

You can attach your another database in onOpen callback. For details see the answer of another post here.

Related

how to Update records in database using where condition in android room?

I am using android room library to maintain local database.
I am trying to update a row of a table by checking the column value just like where clause.
Currently i am using the below code to update the records,
#Update
void update(ProductInfo prodInfo);
My question here is, I want to update the record by using where clause, for example my query is;
Update ProductInfo set (AllColumns) where prodInfo.last_name = 'xyz';
but in room i could not find the answer for that, one option is to write raw query but writing all the column names is very much lengthy.
Can anyone guide me resolving this issue ?
You can use #Query("your update query") to resolve your issue.

ormlite dao delete function not taking parameters

Trying to delete all records from table on a already built app. I has ormlite dao and the function seems very simple
allUsers have a collection of objects to be deleted but i get an Exception :-
SQLException
"java.sql.SQLException: Unable to run delete collection stmt: DELETE FROM user WHERE PIN IN ?,?,?,?,?,)
I tried creating a list of ids and using another option "deleteById" same error
Collection<UserModel> allUsers = helper.getUserDao().queryForAll();
helper.getUserDao().delete(allUsers);
I just need the table to be wiped out.
try it
helper.getUserDao().deleteBuilder().where().eq($yourKey, $yourValue).delete()
I tried creating a list of ids and using another option "deleteById" same error
Collection<UserModel> allUsers = helper.getUserDao().queryForAll();
helper.getUserDao().delete(allUsers);
I'm not sure why this didn't work. If you show more of the exception there may be Caused by sections of the exception that provided more details. It could be that the UserModel doesn't have an ID field?
I just need the table to be wiped out.
There are a couple of ways to do this. The most efficient is use TableUtils.clearTable(...):
TableUtils.clearTable(header.getUserDao().getConnectionSource(), UserModel.class);
Deleting all of the elements can also be done with the DeleteBuilder:
helper.getUserDao().deleteBuilder().delete();

Android Room, SQLite - TO expected, got 'COLUMN'

I'm trying to rename a column in my Room database. I foolishly used the column name index and want to change it to id, but this migration function is causing headaches:
static final Migration MIGRATION_2_3 = new Migration(2, 3) {
#Override
public void migrate(#NonNull SupportSQLiteDatabase database) {
database.execSQL("ALTER TABLE items RENAME COLUMN index TO id;");
}
};
I followed this syntax diagram for the query:
Android Studio is giving me the error TO expected, got 'COLUMN', and I cannot use the database due to the RuntimeException:
Caused by: java.lang.IllegalStateException: Room cannot verify the data integrity. Looks like you've changed schema but forgot to update the version number. You can simply fix this by increasing the version number.
The version number is correct, so I am assuming this issue is caused by the syntax problem above; I cannot find anything else wrong with my setup.
Android uses SQLite v3.19. That makes renaming a column using RENAME COLUMN not possible. The best approach is to recreate the table. – Leo Pelozo
Looks like I need to create function that drops the table so I can create a new one.
#Query("DELETE FROM items")
void dropTable();
... then create the table again, though I'm not sure how to go about this.
Update:
I was able (I think, we'll see...) to re-create the table by calling the above function, removing ALL migrations and setting the database version back to 1. Then I re-defined the database class itself with the proper names etc. and was able to insert data into it without any errors. Adding .fallbackToDestructiveMigration() to my database singleton class was also necessary.
Personally I think this is a little ridiculous just for simply re-naming a column; I was never able to simply rename the column and add a migration for the change, nor was I able to drop the table and re-create it with the proper column name and add that as a migration. But alas, this is Android after all.

Why do I get syntax error when creating a view with column names?

Developing an Android app, but this is a SQLite question.... My SQL is much ropier than my Java.
This is the SQL (copied from a log file, in code it's constructed from various constants):
CREATE VIEW albums (_id, name , type ) AS SELECT rowno, name, subtype FROM metadata WHERE subtype = 'album'
but it throws:
android.database.sqlite.SQLiteException: near "(": syntax error (code 1): , while compiling:
Specifying column names in the view seems to me to be clearly permitted, if I understand the flow chart in the sqlite documentation here, and at this time of night I really can't see what's wrong. I have tried changing the name of the _id column in case it was something to do with the initial underscore, but to no avail and in any case I will need the _id column later for the CursorAdapter that will end up using this View.
At the bottom of the documentation page you linked it states:
Note that the column-name list syntax is only supported in SQLite
versions 3.9.0 and later.
Version 3.9.0 is not supported by Android. Lollipop has 3.7.11. Marshmallow has 3.8.10.2.

Error in Sqlite. Android

I create a database. In this datebase create 3 lines. When I using this database in Android i get this error:
12-18 10:30:10.882: INFO/Database(477): sqlite returned: error code = 11, msg = database corruption found by source line 40107
12-18 10:30:10.882: INFO/Database(477): sqlite returned: error code = 11, msg = database disk image is malformed
This error is obtained, when I do: Select or Insert. How to solve this error?
Delete your app from emulator then install it again, this will create a new database.
EDIT:
Make sure you have a table named android_metadata with a column locale (TEXT), put a string in it (en_US)
A little trick that i do is to create the database normally in the application, I populate it, then i retrieve it from emulator using DDMS or adb (from /data/data/mypackage/databases/nameofthedatabase), and then I put it in the assets. This way I can be sure the database is valid.
Or you can create it in the application, retrieve it, then populate it or modify it (I use sqlitebrowser in linux, works beautifully), then I put it back in /data/data/mypackage/databases/nameofthedatabase, or in assets and copy it there.

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