Develop Reference

SQLite set field to same value as generated id at insert

We have a requirement where some fields in a table need to have the same value as their ID. Unfortunately, we currently have to insert a new record and then, if needed, run another update to set the duplicate field (ID_2) value to equal the ID.
Here is the Android Sqlite code:
mDb.beginTransaction();
// ... setting various fields here ...
ContentValues contentValues = new ContentValues();
contentValues.put(NAME, obj.getName());
// now insert the record
long objId = mDb.insert(TABLE_NAME, null, contentValues);
obj.setId(objId);
// id2 needs to be the same as id:
obj.setId2(objId);
// but we need to persist it so we update it in a SECOND call
StringBuilder query = new StringBuilder();
query.append("update " + TABLE_NAME);
query.append(" set " + ID_2 + "=" + objId);
query.append(" where " + ID + "=" + objId);
mDb.execSQL(query.toString());
mDb.setTransactionSuccessful();
As you can see, we are making a second call to set ID_2 to the same value of ID. Is there any way to set it at INSERT time and avoid the second call to the DB?
Update:
The ID is defined as follows:
ID + " INTEGER PRIMARY KEY NOT NULL ," +

The algorithm used for autoincrementing columns is documented, so you could implement it manually in your code, and then use the new value for the INSERT.

This is quite a ugly hack, but it may be possible :
with id_table as (
select coalesce(max(seq), 0) + 1 as id_column
from sqlite_sequence
where name = 'MY_TABLE'
)
insert into MY_TABLE(ID_1, ID_2, SOME, OTHER, COLUMNS)
select id_column, id_column, 'SOME', 'OTHER', 'VALUES'
from id_table
It only works if the table ID is an AUTOINCREMENT, and is therefore managed via the documented sqlite_sequence table.
I also have no idea what happen in case of concurrent executions.

You could use an AFTER INSERT TRIGGER e.g.
Create your table (at least for this example) so that ID_2 is defined as INTEGER DEFAULT -1 (0 or any negative value would be ok)
e.g. CREATE TABLE IF NOT EXISTS triggertest (_id INTEGER PRIMARY KEY ,name TEXT ,id_2 INTEGER DEFAULT -1);
Then you could use something like (perhaps when straight after the table is created, perhaps create it just before it's to be used and drop it after done with it ) :-
CREATE TRIGGER triggertesting001
AFTER INSERT ON triggertest
BEGIN
UPDATE triggertest SET id_2 = `_id`
WHERE id_2 = -1;
END;
Drop using DROP TRIGGER IF EXISTS triggertesting001;
Example usage (testing):-
INSERT INTO triggertest (name) VALUES('Fred');
INSERT INTO triggertest (name) VALUES('Bert');
INSERT INTO triggertest (name) VALUES('Harry');
Result 1 :-
Result 2 (trigger dropped inserts run again ):-
Result 3 (created trigger) same as above.
Result 4 (ran inserts for 3rd time) catch up i.e. 6 rows updated id_2 with _id.
I'd strongly suggest reading SQL As Understood By SQLite - CREATE TRIGGER
Alternative solution
An alternative approach could be to simply use :-
Before starting transaction, retrieve mynextid from table described below
ContentValues contentValues = new ContentValues();
contentValues.put(ID,mynextid);
contentvalues.put(ID_2,mynextid++);
contentValues.put(NAME, obj.getName());
Then at end of the transactions update/store the value of mynextid in a simple single column, single row table.
i.e. you are managing the id's (not too dissimilar to how SQLite manages id's when 'AUTOINCREMENT' is specified)

android second column returns no value

I have a problem to create a table. If I try to get a value from the second column, android writes a empty space in the toast. But if I try to get a value from the first column, android writes the value of the column correctly. The query functions to write the first column and to write the second column are equal. So I think the Creation of the Table is the problem. But look yourself:
public SQLiteDatabase tabelleerstellen(){
SQLiteDatabase leveldatabase = openOrCreateDatabase("leveldata.db",SQLiteDatabase.CREATE_IF_NECESSARY, null);
leveldatabase.setVersion(1);
final String CREATE_TABLE_LEVEL =
"CREATE TABLE IF NOT EXISTS tbl_level ("
+ "id INTEGER PRIMARY KEY AUTOINCREMENT, "
+ "ME1 TEXT, "
+ "ME2 TEXT, "
+ "ME3 TEXT, "
+ "ME4 TEXT, "
+ "ME5 TEXT, "
+ "ME6 TEXT, "
+ "ME8 TEXT, "
+ "GESCHAFFT INTEGER);";
leveldatabase.execSQL(CREATE_TABLE_LEVEL);
return leveldatabase;
}
public void tester(SQLiteDatabase leveldata){
ContentValues cursortester = new ContentValues();
cursortester.put("ME2","25");
leveldata.insert("tbl_level",null,cursortester);
String[] testerpr = {"ME2"};
Cursor testerprüfen = leveldata.query("tbl_level",testerpr,null,null, null, null,null,null);
testerprüfen.moveToFirst();
String dada = testerprüfen.getString(testerprüfen.getColumnIndex("ME2"));
Toast testertoast = Toast.makeText(getApplicationContext(),dada,Toast.LENGTH_SHORT);
testertoast.show();
}

Please check the following things:
Please make sure the table is up to date .. so try to call DROP TABLE IF EXISTS tbl_level; and recreate the table.
If you run a test make sure the table is completely empty ... so delete everything at the beggining of the test.
If the table can contain elements during the test then make sure you check the last inserted element. Please note that calling testerprüfen.moveToFirst(); moves the cursor to the first row in the table so checking that row every time is even if the table contains 50 elements is not a good thing. In this case you either use a sorting option in your query of uese while (testerprüfen != null && testerprüfen.moveToNext()) {// Your code here}
All in all I think your problem is that you already inserted more that one element in the able but you always check only the first element (with testerprüfen.moveToFirst();). Please not that there is a cursor.moveToLast() method that you can also call. This method moves the cursor to the last row in the table.

Delete specific record in sqlite table based on two criteria: _id and column

I have created a sqlite table for my android app, this table has 5 columns and multiple rows, the columns being: _id, column1, column2, column3, column4.
I want to delete a specific record, for instance the record stored in column3 corresponding to _id (in a different class are the getters and setters, for this I've named the class "TableHandler")
I guess that I'm a bit confused, following is what I was planning, but for column3 I'm not sure what should be the argument, I just want to delete whatever is in that column position corresponding to _id
public void deleteValueColumn3(TableHandler value){
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_NAME, KEY_ID + " = ? AND " + KEY_COLUMN3 + " = ?",
new String[] {String.valueOf(value.getID()), ?????????);
db.close();
}
The ???????? is that I'm stuck there, maybe the whole method needs to be rewritten, I would appreciate your input.
Thanks

If you want to delete the whole record, just use the _id of the record in delete method, because that is the primary key for your table and therefore is unique. If you'd rather keep the record, you con always use the SQLiteDatabase.update method, specifying null as the new value that will replace column3 value; check out that column3 declaration has no NOT NULL tag, otherwise that could easily throw exception at you.

SQLite does not allow you to delete columns for a specific row.
You can only delete ROWS of data (delete the row that has the column _ID = 1).
Here's a quick tutorial on SQL.

How about updating that column with a null value, rather than using delete()?
ContentValues cv = new ContentValues();
cv.putNull(KEY_COLUMN3);
db.getWritableDatabase().update(
TABLE_NAME,
cv,
KEY_ID + "=?",
new String[]{String.valueOf(keyIdValue)});

Get id(s) after applying batch operation

I am applying a batch of ContentProviderOperations on my provider:
ContentProviderResult[] result = resolver.applyBatch(...)
Everything works as expected the data is being inserted into the DB, but if I want to extract the id(s) the last element of the uri which should be the id is always null.
Is this happening because I have set the _id of the table to autoincrement (in other words would it work if I am not autoincrementing the id and fill it with a manually uid from my code).
If not, can anyone tell me whats causing this behavior.
Update: This is the String for creating the table:
private static final String CREATE_TABLE_WORKFLOWSTATES =
"CREATE TABLE " + Tables.WORKFLOWSTATES + " ("
+ BaseColumns._ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ WorkflowStatesColumns.NAME + " TEXT NOT NULL,"
+ "UNIQUE ("+ WorkflowStatesColumns.NAME + ") ON CONFLICT IGNORE)";
and if i view the table I can see the columns _id and name, the inserted data that is visible shows that the autoincrement works properly.
Update 2: This is how I have build the ContentProviderOperation:
this is my ArrayList with ContentProviderOperations (CollectionUtils is a custom class in order to instantiate the Arraylist):
ArrayList<ContentProviderOperation> batch = CollectionUtils.newArrayList();
and this is the actual operation:
batch.add(ContentProviderOperation
.newInsert(InvoiceContract.addCallerIsSyncAdapterParameter(WorkflowStates.CONTENT_URI))
.withValue(WorkflowStates.NAME, task.getWFS()).build());

In case of insertion (and I guess that you insert a row into your database), the result[i].uri contains URI of a newly inserted row, where i is the index of the corresponding operation in operations array. Try to print this URI and you'll see if it corresponds to real id.
If one of your operation is UPDATE or DELETE the corresponding result URI will be null, but result[i].count will contain the number of updated/deleted rows.
UPDATE
I guess the problem is that you have a unique index on NAME. Maybe, you have a row already inserted with the same name?
UPDATE2
The problem was that the insert function in the ContentProvider did not return the id correctly.

Android SQL update table

I am upgrading my database to add another column. What I am trying to do is (after the column is added in onUpgrade) this method is called from the main activity for each table (3 were upgraded). The method is supposed to replace all of the blanks in the new column with "1".
The code runs fine, stepping through, boolean test is true every time but when I open the table to view the data, the entire column is blank. The weird part is, my rowId numbers are incrementing every time. It starts out with 3 rows with rowIds of 1,2,3 respectively. After my code runs once, they now have rowIds of 4,5,6 respectively.
Can anyone help me out? KEY_ROWID is just my auto rowId number. KEY_MODE is just "mode" for column title. If I run through debugging it, the three rows I have show up in the code (it runs through the while loop 3 times).
public void checkBlanks(String table) {
Cursor cursor = mDb.query(table, new String[] {KEY_ROWID, KEY_MODE}, null, null, null, null, null);
while (cursor.moveToNext()) {
int modeCol = cursor.getColumnIndexOrThrow(KEY_MODE);
if (cursor.isNull(modeCol)) {
int rowId = cursor.getInt(cursor.getColumnIndexOrThrow(KEY_ROWID));
ContentValues args = new ContentValues();
args.put(KEY_MODE, 1); // replace the blank space with a "1"
boolean test = mDb.update(table, args, KEY_ROWID + "=" + rowId, null) > 0;
}
}
cursor.close();
}

Instead of manually looping through the rows, why don't you just leverage the power of SQL and update ALL of the rows in one call? E.g.
mDb.execSQL("UPDATE " + table + " SET " + KEY_MODE + " = 1;");
Since it's so simple, you can do this right in your onUpgrade() method.

You could have done that much easier:
1.) During onUpgrade(): "add column newcolumn default 1". This would add a new column with all newcolumns containing 1.
2.) onUpgrade() is already run: update table set newcolumn=1: Without a WHERE clause the whole table is affected.
There's not need to walk thru all rows.
What you want to do requires an SELECT...FOR UPDATE OF/UPDATE...WHERE CURRENT OF. I didn't do that with SQLite, so I don't know if this is supported.
In your situation (onUpgrade is already run) use 2.)