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in this app I`m trying give different welcome message to each type of users
so here is the code in my DB helper class
public int loginCheck(String a,String b)
{
int ty;
SQLiteDatabase db=this.getWritableDatabase();
Cursor c = db.rawQuery("SELECT * FROM users where user_name = '"+a+"'AND user_password = '"+b+"';", null);
ty= c.getInt(c.getColumnIndex("user_type"));
if (c.getCount()<=0)
{
c.close();
db.close();
return 2;
}
else
c.close();
db.close();
return ty;
}
it should check the user type whether 0 or 1 ,, and according to the return value the welcome message appears,what i got that this retrieves the number of the column , it retrieves 6 and "user_type" is the sixth column
You need to move to the first row first:
public int loginCheck(String a,String b) {
int ty;
SQLiteDatabase db=this.getWritableDatabase();
Cursor c = db.rawQuery("SELECT * FROM users where user_name = '"+a+"' AND user_password = '"+b+"';", null);
if (c.moveToFirst()) {
ty = c.getInt(c.getColumnIndex("user_type"));
} else {
ty = 2;
}
c.close();
db.close();
return ty;
}
cursor.moveToFirst will return false if it wasn't able to move to the first row (e.g. the cursor is empty), so no need for the c.getCount() check
=====
The Android way of doing this (not using rawQuery unless have to):
public int loginCheck(String a,String b) {
int ty;
SQLiteDatabase db=this.getWritableDatabase();
Cursor c = db.query("users", new String[] { "user_type" }, "user_name = ? AND user_password = ?", new String[] {a, user_password}, null, null, null);
if (c.moveToFirst()) {
ty = c.getInt(0);
} else {
ty = 2;
}
c.close();
db.close();
return ty;
}
I have a table in my DB, which consists from following fields: id, group_id, uri_id, name, phone.
In my DB manager file I have a function to check if a uri_id exists in group. This is the function:
public boolean is_contact_in_group(String uri_id, int group_id)
{
SQLiteDatabase db = db_helper.getReadableDatabase();
Cursor mContactsCursor = db.query(Constants.TABLE_NAME_GROUP_CONTACTS, null,
"group_id="+group_id+"&contact_uri_id="+uri_id, null, null, null, null);
if(mContactsCursor.moveToFirst())
{
mContactsCursor.close();
db.close();
return true;
} else {
mContactsCursor.close();
db.close();
return false;
}
}
For now In my activity I just want to log the output:
private void add_new_contact(String uri_id, String name, String number)
{
int group_id = curr_group_id;
String contact_uri_id = uri_id;
String contact_name = name;
String contact_phone = number;
Log.i(DEBUG_TAG, "Is contact exist: "+manager.is_contact_in_group(contact_uri_id, group_id));
}
However every time I get false, even if there is a record with a certain group_id and uri_id.
Why is it happening and how to fix it?
I'd imagine it's because your WHERE clause is wrong.
Change
"group_id="+group_id+"&contact_uri_id="+uri_id
to
"group_id="+group_id+" AND contact_uri_id="+uri_id
Try with this.
Cursor mContactsCursor = db.query(Constants.TABLE_NAME_GROUP_CONTACTS, null,
"group_id = " + group_id + " & contact_uri_id = " + uri_id, null, null, null, null);
Your Query has not white spaces between sentences.
I am creating task manager. I have tasklist and I want when I click on particular tasklist name if it empty then it goes on Add Task activity but if it has 2 or 3 tasks then it shows me those tasks into it in list form.
I am trying to get count in list. my database query is like:
public Cursor getTaskCount(long tasklist_Id) {
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor= db.rawQuery("SELECT COUNT (*) FROM " + TABLE_TODOTASK + " WHERE " + KEY_TASK_TASKLISTID + "=?",
new String[] { String.valueOf(tasklist_Id) });
if(cursor!=null && cursor.getCount()!=0)
cursor.moveToNext();
return cursor;
}
In My activity:
list_tasklistname.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0,
android.view.View v, int position, long id) {
db = new TodoTask_Database(getApplicationContext());
Cursor c = db.getTaskCount(id);
System.out.println(c.getCount());
if(c.getCount()>0) {
System.out.println(c);
Intent taskListID = new Intent(getApplicationContext(), AddTask_List.class);
task = adapter.getItem(position);
int taskList_id = task.getTaskListId();
taskListID.putExtra("TaskList_ID", taskList_id);
startActivity(taskListID);
}
else {
Intent addTask = new Intent(getApplicationContext(), Add_Task.class);
startActivity(addTask);
}
}
});
db.close();
}
but when I am clicking on tasklist name it is returning 1, bot number of tasks into it.
Using DatabaseUtils.queryNumEntries():
public long getProfilesCount() {
SQLiteDatabase db = this.getReadableDatabase();
long count = DatabaseUtils.queryNumEntries(db, TABLE_NAME);
db.close();
return count;
}
or (more inefficiently)
public int getProfilesCount() {
String countQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int count = cursor.getCount();
cursor.close();
return count;
}
In Activity:
int profile_counts = db.getProfilesCount();
db.close();
Use android.database.DatabaseUtils to get number of count.
public long getTaskCount(long tasklist_Id) {
return DatabaseUtils.queryNumEntries(readableDatabase, TABLE_NAME);
}
It is easy utility that has multiple wrapper methods to achieve database operations.
c.getCount() returns 1 because the cursor contains a single row (the one with the real COUNT(*)). The count you need is the int value of first row in cursor.
public int getTaskCount(long tasklist_Id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor= db.rawQuery(
"SELECT COUNT (*) FROM " + TABLE_TODOTASK + " WHERE " + KEY_TASK_TASKLISTID + "=?",
new String[] { String.valueOf(tasklist_Id) }
);
int count = 0;
if(null != cursor)
if(cursor.getCount() > 0){
cursor.moveToFirst();
count = cursor.getInt(0);
}
cursor.close();
}
db.close();
return count;
}
I know it is been answered long time ago, but i would like to share this also:
This code works very well:
SQLiteDatabase db = this.getReadableDatabase();
long taskCount = DatabaseUtils.queryNumEntries(db, TABLE_TODOTASK);
BUT what if i dont want to count all rows and i have a condition to apply?
DatabaseUtils have another function for this: DatabaseUtils.longForQuery
long taskCount = DatabaseUtils.longForQuery(db, "SELECT COUNT (*) FROM " + TABLE_TODOTASK + " WHERE " + KEY_TASK_TASKLISTID + "=?",
new String[] { String.valueOf(tasklist_Id) });
The longForQuery documentation says:
Utility method to run the query on the db and return the value in the first column of the first row.
public static long longForQuery(SQLiteDatabase db, String query, String[] selectionArgs)
It is performance friendly and save you some time and boilerplate code
Hope this will help somebody someday :)
Change your getTaskCount Method to this:
public int getTaskCount(long tasklist_id){
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor= db.rawQuery("SELECT COUNT (*) FROM " + TABLE_TODOTASK + " WHERE " + KEY_TASK_TASKLISTID + "=?", new String[] { String.valueOf(tasklist_id) });
cursor.moveToFirst();
int count= cursor.getInt(0);
cursor.close();
return count;
}
Then, update the click handler accordingly:
public void onItemClick(AdapterView<?> arg0, android.view.View v, int position, long id) {
db = new TodoTask_Database(getApplicationContext());
// Get task list id
int tasklistid = adapter.getItem(position).getTaskListId();
if(db.getTaskCount(tasklistid) > 0) {
System.out.println(c);
Intent taskListID = new Intent(getApplicationContext(), AddTask_List.class);
taskListID.putExtra("TaskList_ID", tasklistid);
startActivity(taskListID);
} else {
Intent addTask = new Intent(getApplicationContext(), Add_Task.class);
startActivity(addTask);
}
}
In order to query a table for the number of rows in that table, you want your query to be as efficient as possible. Reference.
Use something like this:
/**
* Query the Number of Entries in a Sqlite Table
* */
public long QueryNumEntries()
{
SQLiteDatabase db = this.getReadableDatabase();
return DatabaseUtils.queryNumEntries(db, "table_name");
}
Do you see what the DatabaseUtils.queryNumEntries() does? It's awful!
I use this.
public int getRowNumberByArgs(Object... args) {
String where = compileWhere(args);
String raw = String.format("SELECT count(*) FROM %s WHERE %s;", TABLE_NAME, where);
Cursor c = getWriteableDatabase().rawQuery(raw, null);
try {
return (c.moveToFirst()) ? c.getInt(0) : 0;
} finally {
c.close();
}
}
Sooo simple to get row count:
cursor = dbObj.rawQuery("select count(*) from TABLE where COLUMN_NAME = '1' ", null);
cursor.moveToFirst();
String count = cursor.getString(cursor.getColumnIndex(cursor.getColumnName(0)));
looking at the sources of DatabaseUtils we can see that queryNumEntries uses a select count(*)... query.
public static long queryNumEntries(SQLiteDatabase db, String table, String selection,
String[] selectionArgs) {
String s = (!TextUtils.isEmpty(selection)) ? " where " + selection : "";
return longForQuery(db, "select count(*) from " + table + s,
selectionArgs);
}
Once you get the cursor you can do
Cursor.getCount()
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
What is the most efficient method of showing my data in descending order?
public String getRank() {
String[] rank = new String[]{ KEY_ROWID };
Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, null); //reading information from db.
String rankResult = "";
int iRow = c.getColumnIndex(KEY_ROWID); //Cursor looking for column setting equal to these ints.
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
//Move to first row - where cursor starts and moves to next row as long it is not after last row.
rankResult = rankResult + c.getString(iRow) + "\n";
//Returning value of row that it is currently on.
}
return rankResult; //returning result
}
public String getName() {
String[] name = new String[]{ KEY_NAME };
Cursor c = scoreDb.query(DATABASE_TABLE, name, null, null, null, null, null); //reading information from db.
String nameResult = "";
int iRow1 = c.getColumnIndex(KEY_NAME); //Cursor looking for column setting equal to these ints.
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
//Move to first row - where cursor starts and moves to next row as long it is not after last row.
nameResult = nameResult + c.getString(iRow1) + "\n";
//Returning value of row that it is currently on.
}
return nameResult; //returning result
}
public String getScore() {
String[] score = new String[]{ KEY_SCORE };
Cursor c = scoreDb.query(DATABASE_TABLE, score, null, null, null,null, null); //reading information from db.
String scoreResult = "";
int iRow2 = c.getColumnIndex(KEY_SCORE); //Cursor looking for column setting equal to these ints.
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
//Move to first row - where cursor starts and moves to next row as long it is not after last row.
scoreResult = scoreResult + c.getString(iRow2) + "\n";
//Returning value of row that it is currently on.
}
return scoreResult; //returning result
}
Query has two syntax, the syntax you are using, last column represents orderBy, you just need to specify on what column you want to do orderBy +"ASC" (or) orderBy +"DESC"
Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, yourColumn+" DESC");
Refer this documentation to understand more about query() method.
return database.rawQuery("SELECT * FROM " + DbHandler.TABLE_ORDER_DETAIL +
" ORDER BY "+DbHandler.KEY_ORDER_CREATED_AT + " DESC"
, new String[] {});
Cursor c = scoreDb.query(Table_Name, score, null, null, null, null, Column+" DESC");
Try this
According to docs:
public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit);
and your ORDER BY param means:
How to order the rows, formatted as an SQL ORDER BY clause
(excluding the ORDER BY itself). Passing null will use the default
sort order, which may be unordered.
So, your query will be:
Cursor cursor = db.query(TABLE_NAME, null, null,
null, null, null, KEY_ITEM + " DESC", null);
public List getExpensesList(){
SQLiteDatabase db = this.getWritableDatabase();
List<String> expenses_list = new ArrayList<String>();
String selectQuery = "SELECT * FROM " + TABLE_NAME ;
Cursor cursor = db.rawQuery(selectQuery, null);
try{
if (cursor.moveToLast()) {
do{
String info = cursor.getString(cursor.getColumnIndex(KEY_DESCRIPTION));
expenses_list.add(info);
}while (cursor.moveToPrevious());
}
}finally{
cursor.close();
}
return expenses_list;
}
This is my way of reading the record from database for list view in descending order. Move the cursor to last and move to previous record after each record is fetched. Hope this helps~
Cursor c = myDB.rawQuery("SELECT distinct p_name,p_price FROM products order by Id desc",new String[]{});
this works for me!!!
you can do it with this
Cursor cursor = database.query(
TABLE_NAME,
YOUR_COLUMNS, null, null, null, null, COLUMN_INTEREST+" DESC");
SQLite ORDER BY clause is used to sort the data in an ascending or descending order, based on one or more columns.
Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, yourColumn+" DESC");
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(
TABLE_NAME,
rank,
null,
null,
null,
null,
COLUMN + " DESC",
null);
We have one more option to do order by
public Cursor getlistbyrank(String rank) {
try {
//This can be used
return db.`query("tablename", null, null, null, null, null, rank +"DESC",null );
OR
return db.rawQuery("SELECT * FROM table order by rank", null);
} catch (SQLException sqle) {
Log.e("Exception on query:-", "" + sqle.getMessage());
return null;
}
}
You can use this two method for order
This a terrible thing! It costs my a few hours!
this is my table rows :
private String USER_ID = "user_id";
private String REMEMBER_UN = "remember_un";
private String REMEMBER_PWD = "remember_pwd";
private String HEAD_URL = "head_url";
private String USER_NAME = "user_name";
private String USER_PPU = "user_ppu";
private String CURRENT_TIME = "current_time";
Cursor c = db.rawQuery("SELECT * FROM " + TABLE +" ORDER BY " + CURRENT_TIME + " DESC",null);
Every time when I update the table , I will update the CURRENT_TIME for sort.
But I found that it is not work.The result is not sorted what I want.
Finally, I found that, the column "current_time" is the default row of sqlite.
The solution is, rename the column "cur_time" instead of "current_time".
About efficient method. You can use CursorLoader. For example I included my action. And you must implement ContentProvider for your data base. https://developer.android.com/reference/android/content/ContentProvider.html
If you implement this, you will call you data base very efficient.
public class LoadEntitiesActionImp implements LoaderManager.LoaderCallbacks<Cursor> {
public interface OnLoadEntities {
void onSuccessLoadEntities(List<Entities> entitiesList);
}
private OnLoadEntities onLoadEntities;
private final Context context;
private final LoaderManager loaderManager;
public LoadEntitiesActionImp(Context context, LoaderManager loaderManager) {
this.context = context;
this.loaderManager = loaderManager;
}
public void setCallback(OnLoadEntities onLoadEntities) {
this.onLoadEntities = onLoadEntities;
}
public void loadEntities() {
loaderManager.initLoader(LOADER_ID, null, this);
}
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(context, YOUR_URI, null, YOUR_SELECTION, YOUR_ARGUMENTS_FOR_SELECTION, YOUR_SORT_ORDER);
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
}
#Override
public void onLoaderReset(Loader<Cursor> loader) {
}