rawQuery(query, selectionArgs)

rawQuery(query, selectionArgs) - android

I want to use select query for retrieving data from table. I have found, rawQuery(query, selectionArgs) method of SQLiteDatabase class to retrieve data. But I don't know how the query and selectionArgs should be passed to rawQuery method?

rawQuery("SELECT id, name FROM people WHERE name = ? AND id = ?", new String[] {"David", "2"});
You pass a string array with an equal number of elements as you have "?"

Maybe this can help you
Cursor c = db.rawQuery("query",null);
int id[] = new int[c.getCount()];
int i = 0;
if (c.getCount() > 0)
{
c.moveToFirst();
do {
id[i] = c.getInt(c.getColumnIndex("field_name"));
i++;
} while (c.moveToNext());
c.close();
}

One example of rawQuery - db.rawQuery("select * from table where column = ?",new String[]{"data"});

if your SQL query is this
SELECT id,name,roll FROM student WHERE name='Amit' AND roll='7'
then rawQuery will be
String query="SELECT id, name, roll FROM student WHERE name = ? AND roll = ?";
String[] selectionArgs = {"Amit","7"}
db.rawQuery(query, selectionArgs);

see below code it may help you.
String q = "SELECT * FROM customer";
Cursor mCursor = mDb.rawQuery(q, null);
or
String q = "SELECT * FROM customer WHERE _id = " + customerDbId ;
Cursor mCursor = mDb.rawQuery(q, null);

For completeness and correct resource management:
ICursor cursor = null;
try
{
cursor = db.RawQuery("SELECT * FROM " + RECORDS_TABLE + " WHERE " + RECORD_ID + "=?", new String[] { id + "" });
if (cursor.Count > 0)
{
cursor.MoveToFirst();
}
return GetRecordFromCursor(cursor); // Copy cursor props to custom obj
}
finally // IMPORTANT !!! Ensure cursor is not left hanging around ...
{
if(cursor != null)
cursor.Close();
}

String mQuery = "SELECT Name,Family From tblName";
Cursor mCur = db.rawQuery(mQuery, new String[]{});
mCur.moveToFirst();
while ( !mCur.isAfterLast()) {
String name= mCur.getString(mCur.getColumnIndex("Name"));
String family= mCur.getString(mCur.getColumnIndex("Family"));
mCur.moveToNext();
}
Name and family are your result

Related

Android: Get entire column data

Im trying to get the data of an entire column into a string array. My database contains two columns Id and Names. I want to read all the entries of the names column and put it into a array. Please help.
EDIT #1:
Im using the following code but i can get only one name with this code.
String query = "Select * FROM " + TABLE_APPS + " WHERE " + COLUMN_NAME + " = \"" + productname + "\"";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
if (cursor.moveToFirst()) {
cursor.moveToFirst();
name = cursor.getString(1);
cursor.close();
} else {
name = null;
}
db.close();

int total=0;
Cursor csr=sdb.query("tablename", null, null,null,null,null,null);
csr.moveToFirst();
while(!csr.isAfterLast())
{
total++;
csr.moveToNext();
}
String strarray[] = new String[total];
Cursor csrs=sdb.query("tablename", null, null,null,null,null,null);
csrs.moveToFirst();
int aray=0;
while(!csrs.isAfterLast())
{
strarray[aray]=csrs.getString(1);
aray++;
csrs.moveToNext();
}

Android SQLite Query: Trouble with WHERE clause

Please let me know why my where clause isn't working. I tried using the query instead of rawquery but no luck.
try {
String categoryex = "NAME";
DBHelper dbHelper = new DBHelper(this.getApplicationContext());
MyData = dbHelper.getWritableDatabase();
Cursor c = MyData.rawQuery("SELECT * FROM " + tableName + where Category = '+categoryex'" , null);
if (c != null ) {
if (c.moveToFirst()) {
do {
String firstName = c.getString(c.getColumnIndex("Category"));
String age = c.getString(c.getColumnIndex("Text_Data"));
results.add( firstName + " Directions: " + age);
}while (c.moveToNext());
}
}
} catch (SQLiteException se ) {
Log.e(getClass().getSimpleName(), "Could not create or Open the database");
} finally {
if (MyData != null)
MyData.execSQL("DELETE FROM " + tableName);
MyData.close();
}

try... (you left out a double-quote before where.
Cursor c = MyData.rawQuery("SELECT * FROM " + tableName + " where Category = '" +categoryex + "'" , null);

I think you should use rawQuery in this form:
rawQuery("SELECT * FROM ? where Category = ?", new String[] {tableName, categoryex});
I think it's more secure this way.

Your quotes are buggered:
Cursor c = MyData.rawQuery("SELECT * FROM " + tableName + " where Category = '" + categoryex + "'" , null);
You also should read up on SQL injection attacks.

it will be more easy if you use this technique instead of rawQuery,its easy way change your table name, columns and where conditions accordingly.
public ArrayList<Invitees> getGroupMembers(String group_name) {
ArrayList<Invitees> contacts = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
String[] projection = {COLUMN_CONTACT, COLUMN_PHONE_NUMBER};
String selection = COLUMN_GROUP_NAME + "=?";
String[] selectionArgs = {group_name};
Cursor cursor = db.query(GROUPS_TABLE_NAME, projection, selection, selectionArgs, null, null, null);
if (cursor.moveToFirst()) {
do {
Invitees invitees = new Invitees();
invitees.setUserName(cursor.getString(cursor.getColumnIndexOrThrow(COLUMN_CONTACT)));
invitees.setInviteePhone(cursor.getString(cursor.getColumnIndexOrThrow(COLUMN_PHONE_NUMBER)));
contacts.add(invitees);
} while (cursor.moveToNext());
}
return contacts;
}

How to get the first column data in sqlite database?

I am trying to get the first column like below sql but my code show error.
SELECT subject FROM setting WHERE rowid=1
public void getSetting(){
result = "";
SQLiteDatabase db = myDbHelper.getReadableDatabase();
Cursor c = db.query(true, "setting", new String[] {"subject", "language", "selection"}, "row=1", null, null, null, null, null);
for(c.moveToFirst();!(c.isAfterLast());c.moveToNext()){
result = result + c.getString(0);
result = result + c.getString(0);
result = result + c.getString(0);
}
if (c.getCount() == 0)
result = result + "result not found";
c.close();
db.close();
myDbHelper.close();
}

Your stuff is a little hard to understand, but i think i have an idea what you want. You what to get a cursor to return only one row where the row's id is a specific value. And you only want the string from one column of that returned row. I assume that the primary issue is your designation of the _id column that you're looking for. You either called it row or rowid, you gotta double-check that.
Moreover, i hope the following re-write clears up further issues that you might have.
public String getSetting() {
String result = "";
String[] columns = {"subject"};
String[] selectionArgs = {"1"};
String LIMIT = String.valueOf(1); // <-- number of results we want/expect
SQLiteDatabase db = myDbHelper.getReadableDatabase();
Cursor c = db.query(true, "setting", columns, "rowid = ?", selectionArgs, null, null, null, LIMIT);
if (c.moveToFirst()) {
result = result + c.getString(0);
} else {
result = result + "result not found";
}
c.close();
myDbHelper.close();
return result;
}
Moreover, moreover. If you get an error you should post it so that we have an idea what's going on.

Cursor returning null

public String getContact(String searchName) {
SQLiteDatabase db = this.getReadableDatabase();
String[] args = { searchName };
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_MOVIES
+ " WHERE name =? ", args);
String iName = null, iDiretor = null, iGenre = null;
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
iName = cursor.getString(cursor.getColumnIndex(KEY_NAME));
iDiretor = cursor.getString(cursor.getColumnIndex(KEY_DIRECTOR));
iGenre = cursor.getString(cursor.getColumnIndex(KEY_GENRE));
cursor.moveToNext();
}
cursor.close();
The iName variable is working fine but the other two are returning null. Any help?

Use the SQLiteDatabase query methods instead of rawQuery for the best results.
db.query(TABLE_MOVIES, null, "name = ?", args, null);
This is preferred because rawQuery is easy to mess up and doesn't protect against SQL injections.

Try this way:
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_MOVIES + " WHERE name LIKE ? ", args);

Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_MOVIES
+ " WHERE name LIKE "+searchName, null); // Put Like When your are comparing String

IN clause and placeholders

I'm attempting to do the following SQL query within Android:
String names = "'name1', 'name2"; // in the code this is dynamically generated
String query = "SELECT * FROM table WHERE name IN (?)";
Cursor cursor = mDb.rawQuery(query, new String[]{names});
However, Android does not replace the question mark with the correct values. I could do the following, however, this does not protect against SQL injection:
String query = "SELECT * FROM table WHERE name IN (" + names + ")";
Cursor cursor = mDb.rawQuery(query, null);
How can I get around this issue and be able to use the IN clause?

A string of the form "?, ?, ..., ?" can be a dynamically created string and safely put into the original SQL query (because it is a restricted form that does not contain external data) and then the placeholders can be used as normal.
Consider a function String makePlaceholders(int len) which returns len question-marks separated with commas, then:
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + makePlaceholders(names.length) + ")";
Cursor cursor = mDb.rawQuery(query, names);
Just make sure to pass exactly as many values as places. The default maximum limit of host parameters in SQLite is 999 - at least in a normal build, not sure about Android :)
Here is one implementation:
String makePlaceholders(int len) {
if (len < 1) {
// It will lead to an invalid query anyway ..
throw new RuntimeException("No placeholders");
} else {
StringBuilder sb = new StringBuilder(len * 2 - 1);
sb.append("?");
for (int i = 1; i < len; i++) {
sb.append(",?");
}
return sb.toString();
}
}

Short example, based on answer of user166390:
public Cursor selectRowsByCodes(String[] codes) {
try {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String[] sqlSelect = {COLUMN_NAME_ID, COLUMN_NAME_CODE, COLUMN_NAME_NAME, COLUMN_NAME_PURPOSE, COLUMN_NAME_STATUS};
String sqlTables = "Enumbers";
qb.setTables(sqlTables);
Cursor c = qb.query(db, sqlSelect, COLUMN_NAME_CODE+" IN (" +
TextUtils.join(",", Collections.nCopies(codes.length, "?")) +
")", codes,
null, null, null);
c.moveToFirst();
return c;
} catch (Exception e) {
Log.e(this.getClass().getCanonicalName(), e.getMessage() + e.getStackTrace().toString());
}
return null;
}

Sadly there's no way of doing that (obviously 'name1', 'name2' is not a single value and can therefore not be used in a prepared statement).
So you will have to lower your sights (e.g. by creating very specific, not reusable queries like WHERE name IN (?, ?, ?)) or not using stored procedures and try to prevent SQL injections with some other techniques...

As suggest in accepted answer but without using custom function to generate comma-separated '?'. Please check code below.
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + TextUtils.join(",", Collections.nCopies(names.length, "?")) + ")";
Cursor cursor = mDb.rawQuery(query, names);

You can use TextUtils.join(",", parameters) to take advantage of sqlite binding parameters, where parameters is a list with "?" placeholders and the result string is something like "?,?,..,?".
Here is a little example:
Set<Integer> positionsSet = membersListCursorAdapter.getCurrentCheckedPosition();
List<String> ids = new ArrayList<>();
List<String> parameters = new ArrayList<>();
for (Integer position : positionsSet) {
ids.add(String.valueOf(membersListCursorAdapter.getItemId(position)));
parameters.add("?");
}
getActivity().getContentResolver().delete(
SharedUserTable.CONTENT_URI,
SharedUserTable._ID + " in (" + TextUtils.join(",", parameters) + ")",
ids.toArray(new String[ids.size()])
);

Actually you could use android's native way of querying instead of rawQuery:
public int updateContactsByServerIds(ArrayList<Integer> serverIds, final long groupId) {
final int serverIdsCount = serverIds.size()-1; // 0 for one and only id, -1 if empty list
final StringBuilder ids = new StringBuilder("");
if (serverIdsCount>0) // ambiguous "if" but -1 leads to endless cycle
for (int i = 0; i < serverIdsCount; i++)
ids.append(String.valueOf(serverIds.get(i))).append(",");
// add last (or one and only) id without comma
ids.append(String.valueOf(serverIds.get(serverIdsCount))); //-1 throws exception
// remove last comma
Log.i(this,"whereIdsList: "+ids);
final String whereClause = Tables.Contacts.USER_ID + " IN ("+ids+")";
final ContentValues args = new ContentValues();
args.put(Tables.Contacts.GROUP_ID, groupId);
int numberOfRowsAffected = 0;
SQLiteDatabase db = dbAdapter.getWritableDatabase());
try {
numberOfRowsAffected = db.update(Tables.Contacts.TABLE_NAME, args, whereClause, null);
} catch (Exception e) {
e.printStackTrace();
}
dbAdapter.closeWritableDB();
Log.d(TAG, "updateContactsByServerIds() numberOfRowsAffected: " + numberOfRowsAffected);
return numberOfRowsAffected;
}

This is not Valid
String subQuery = "SELECT _id FROM tnl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
"?" +
")",
new String[]{subQuery}););
This is Valid
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
subQuery +
")",
null);
Using ContentResolver
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun' ";
final String[] selectionArgs = new String[]{"1","2"};
final String selection = "_id IN ( ?,? )) AND part_of_speech_id IN (( " + subQuery + ") ";
SQLiteDatabase SQLDataBase = DataBaseManage.getReadableDatabase(this);
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables("tableName");
Cursor cursor = queryBuilder.query(SQLDataBase, null, selection, selectionArgs, null,
null, null);

In Kotlin you can use joinToString
val query = "SELECT * FROM table WHERE name IN (${names.joinToString(separator = ",") { "?" }})"
val cursor = mDb.rawQuery(query, names.toTypedArray())

I use the Stream API for this:
final String[] args = Stream.of("some","data","for","args").toArray(String[]::new);
final String placeholders = Stream.generate(() -> "?").limit(args.length).collect(Collectors.joining(","));
final String selection = String.format("SELECT * FROM table WHERE name IN(%s)", placeholders);
db.rawQuery(selection, args);

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

rawQuery(query, selectionArgs) - android

I want to use select query for retrieving data from table. I have found, rawQuery(query, selectionArgs) method of SQLiteDatabase class to retrieve data. But I don't know how the query and selectionArgs should be passed to rawQuery method?

rawQuery("SELECT id, name FROM people WHERE name = ? AND id = ?", new String[] {"David", "2"}); You pass a string array with an equal number of elements as you have "?"

Maybe this can help you Cursor c = db.rawQuery("query",null); int id[] = new int[c.getCount()]; int i = 0; if (c.getCount() > 0) { c.moveToFirst(); do { id[i] = c.getInt(c.getColumnIndex("field_name")); i++; } while (c.moveToNext()); c.close(); }

One example of rawQuery - db.rawQuery("select * from table where column = ?",new String[]{"data"});

if your SQL query is this SELECT id,name,roll FROM student WHERE name='Amit' AND roll='7' then rawQuery will be String query="SELECT id, name, roll FROM student WHERE name = ? AND roll = ?"; String[] selectionArgs = {"Amit","7"} db.rawQuery(query, selectionArgs);

see below code it may help you. String q = "SELECT * FROM customer"; Cursor mCursor = mDb.rawQuery(q, null); or String q = "SELECT * FROM customer WHERE _id = " + customerDbId ; Cursor mCursor = mDb.rawQuery(q, null);

Related

Android: Get entire column data

Android SQLite Query: Trouble with WHERE clause

How to get the first column data in sqlite database?

Cursor returning null

IN clause and placeholders

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