I would to like to display data from a local database table according to a user condition.
Code to display:
public void viewContact(){
String name = getIntent().getStringExtra("name").toString();
tvName.setText(name);
String phone = db.getContacts(name).toString();
tvPhone.setText(phone);
String web = db.getContacts(name.toString();
tvWeb.setText(web);
}
DBHelper.class:
public Cursor getContacts(String therapist_name){
String selectQuery = " SELECT therapist_phone, therapist_web " +
" FROM " + THERAPIST_TABLE + " WHERE " + THERA_NAME + " = " + "'" + therapist_name + "'";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
return cursor;
}
Can anyone point out where I've gone wrong?
Explanation:
The activity receives contact name from previous activity (hence getIntent()). Then with that, it would like to view data from database relating to the contact and thus would like to view the phone_number and website columns.
So if therapist_name is equal that of selected contact from previous activity, it would only display the therapist_number and therapist_website of that contact in the next activity.
You should have an Object Contact with the properties you want, and everytime you run the query, go trough the steps Ana said of checking if the cursor is null and moving to first (i personally check the size of the cursor also, to Log an error if is empty).
And then return the created object, so when you call the method, you have everything there, something like this:
public List<Contact> getContacts(String therapist_name){
List<Contact> listOfContacts = new ArrayList<>();
String selectQuery = " SELECT therapist_phone, therapist_web " +
" FROM " + THERAPIST_TABLE + " WHERE " + THERA_NAME + " = " + "'" + therapist_name + "'";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
//Save data in variables here
String ph_no = cursor.getString(0); // therapist contact
String web = cursor.getString(1); //therapist web
listOfContacts.add(new Contact(ph_no, web));
} while (cursor.moveToNext());
}
}
return listOfContacts;
}
This returns a list of objects, just in case there is more than one match. You can tweak it to get one, or the first match, and return just the Contact object, so you would have your data,
You are just returning cursor object. Read the data and then return the retrieved data.
Example:
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
//Save data in variables here
ph_no = cursor.getString(0); // therapist contact
web = cursor.getString(1); //therapist web
} while (cursor.moveToNext());
}
}
//pass an array of ph_no and web from here now
I'm getting a null pointer exception on the following line of code
attendanceList = dbHelper.getAttendance(surName, name);
both surName and name are not null, have size() > 0 and attendanceList is of type ArrayList and here is the getAttendance function:
public ArrayList<Attendance> getAttendance(String surName, String name)
{
SQLiteDatabase db = this.getReadableDatabase();
ArrayList<Attendance> attendanceList = new ArrayList<>();
Cursor cursor = db.rawQuery("SELECT * FROM " + ATTENDANCE_TABLE + " WHERE " + COLUMN_SURNAME + " =? AND "
+ COLUMN_NAME + " =?", new String[] {surName, name});
if(cursor .moveToFirst())
{
while(!cursor.isAfterLast())
{
Attendance attendance = new Attendance();
attendance.setDate(cursor.getString(cursor.getColumnIndex(COLUMN_DATE)));
attendance.setName(cursor.getString(cursor.getColumnIndex(COLUMN_NAME)));
attendance.setSurName(cursor.getString(cursor.getColumnIndex(COLUMN_SURNAME)));
attendance.setState(cursor.getString(cursor.getColumnIndex(COLUMN_STATE)));
attendance.setTerm(cursor.getInt(cursor.getColumnIndex(COLUMN_TERM)));
attendance.setSubject(cursor.getString(cursor.getColumnIndex(COLUMN_SUBJECT_NAME)));
attendanceList.add(attendance);
cursor.moveToNext();
}
cursor.close();
db.close();
return attendanceList;
}
else
{
cursor.close();
db.close();
return null;
}
}
There is no syntax error in the above function, and I know it shouldn't return null because I see the content of the ATTENDANCE_TABLE using DB Browser for SQLite. Can someone point what is wrong with my code? I feel like I wrote 1 + 1 = 2 and getting an error..
Try this... SQLiteDbHelper is my DataBase Class where my table is defined. Table_Name is string in which my table name is stored
cursor = db.rawQuery("SELECT * FROM "+SQLiteDBHelper.TABLE_NAME+" WHERE "+SQLiteDBHelper.COLUMN_SURNAME+"=? AND "+SQLiteDBHelper.COLUMN_NAME+"=?",new String[] {surName,name});
if (cursor != null) {
if(cursor.getCount() > 0) {
cursor.moveToFirst();
//Retrieving User SurName and Name
String s_name = cursor.getString(cursor.getColumnIndex(SQLiteDBHelper.COLUMN_SURNAME));
String _name= cursor.getString(cursor.getColumnIndex(SQLiteDBHelper.COLUMN_NAME));
Toast.makeText(MainActivity.this, "Success", Toast.LENGTH_SHORT).show();
I am pretty sure that it not surName or name that causes NullpointerException, but dbHelper is.
So please check if you are initialising your dbHelper after this line
attendanceList = dbHelper.getAttendance(surName, name);
If so, then move it above and your crash will be fixed.
Hope it helps.
i have an issue with both functions
// Insert a new contact in database
public void insertInSignature(String TITLE_SI) {
try {
// Open Android Database
Boolean b = checkIsDataAlreadyInDBorNot("DELIVERY_SLIP",
"TITLE_SI", TITLE_SI);
if(b==false)
{
// cursor is empty
ContentValues initialValues = new ContentValues();
initialValues.put("TITLE_SI", TITLE_SI);
db.insertWithOnConflict("DELIVERY_SLIP", null, initialValues,
SQLiteDatabase.CONFLICT_IGNORE);
}
} catch (SQLException sqle) {
Log.e(TAG, "insertUser Error");
Log.e(TAG, "Exception : " + sqle);
} finally {
// Close Android Database
databaseHelper.close();
}
}
public boolean checkIsDataAlreadyInDBorNot(String TableName,
String dbfield, String fieldValue) {
db = databaseHelper.getWritableDatabase();
String Query = "Select * from " + TableName + " where " + dbfield + "="
+ "`"+ fieldValue+"`";
Cursor cursor = db.rawQuery(Query, null);
if (cursor.getCount() <= 0) {
return false;
}
return true;
}
I have this function , I'm inserting signature when it's not on the database.. But the function boolean return an SQLexception i don't know why i found informations about the form , but not for my problem.
Here my log.
http://hpics.li/0ae4ba2
I just want to know if the row exist on my database
here my table.
http://hpics.li/1fd3d9a
Thanks by advance if you need for informations ask me
In SQL, strings are delimited with single quotes ', not backticks `.
To avoid such formatting problems, and SQL injections, you should use parameters instead:
String query = "SELECT * FROM " + TableName + " WHERE " + dbfield + "= ?";
Cursor cursor = db.rawQuery(query, new String[] { fieldValue });
Instead of doing a query every time you want to insert, why not make the TITLE_SI column UNIQUE with ON CONFLICT IGNORE or ONC CONFLICT REPLACE? Then you don't need to check, you simply insert and let the uniqueness constraint manage this for you.
I would like to check whether a record exists or not.
Here is what I've tried:
MainActivity.class
public void onTextChanged(CharSequence s, int start, int before, int count) {
System.out.println("Ontext changed " + new String(s.toString()));
strDocumentFrom = s.toString();
if(s.toString().isEmpty()){
} else {
try{
strTransactionDate = dbHelper.getTransactionDateByDocumentNumber(strDocumentFrom);
//strTotalAmount = dbHelper.getTotalAmountByDocumentNumber(strDocumentFrom);
//strVan = dbHelper.getVanByDocumentNumber(strDocumentFrom);
//etTransactionDate.setText(strTransactionDate);
//etTotalAmount.setText(strTotalAmount);
//Log.d("Van", "" + strVan);
//etVan.setText(strVan);
} catch (SQLiteException e) {
e.printStackTrace();
Toast.makeText(ReceivingStocksHeader.this,
"Document number does not exist.", Toast.LENGTH_SHORT).show();
}
}
DBHelper.class
// TODO DISPLAYING RECORDS TO TRANSRCVHEADER
public String getTransactionDateByDocumentNumber(String strDocumentNumber){
String[] columns = new String[]{KEY_TRANSACTIONDATE};
Cursor c = myDataBase.query(TBL_INTRANS,
columns, null,
null, null, null, null, null);
if(c != null){
c.moveToFirst();
String date = c.getString(0);
return date;
} else {
Log.d("Error", "No record exists");
}
return null;
}
But it doesn't get it to the catch block to display the toast.
What am I doing wrong in here?
public static boolean CheckIsDataAlreadyInDBorNot(String TableName,
String dbfield, String fieldValue) {
SQLiteDatabase sqldb = EGLifeStyleApplication.sqLiteDatabase;
String Query = "Select * from " + TableName + " where " + dbfield + " = " + fieldValue;
Cursor cursor = sqldb.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursor.close();
return false;
}
cursor.close();
return true;
}
I hope this is useful to you...
This function returns true if record already exists in db. Otherwise returns false.
These are all good answers, however many forget to close the cursor and database. If you don't close the cursor or database you may run in to memory leaks.
Additionally: You can get an error when searching by String that contains non alpha/numeric characters. For example: "1a5f9ea3-ec4b-406b-a567-e6927640db40". Those dashes (-) will cause an unrecognized token error. You can overcome this by putting the string in an array. So make it a habit to query like this:
public boolean hasObject(String id) {
SQLiteDatabase db = getWritableDatabase();
String selectString = "SELECT * FROM " + _TABLE + " WHERE " + _ID + " =?";
// Add the String you are searching by here.
// Put it in an array to avoid an unrecognized token error
Cursor cursor = db.rawQuery(selectString, new String[] {id});
boolean hasObject = false;
if(cursor.moveToFirst()){
hasObject = true;
//region if you had multiple records to check for, use this region.
int count = 0;
while(cursor.moveToNext()){
count++;
}
//here, count is records found
Log.d(TAG, String.format("%d records found", count));
//endregion
}
cursor.close(); // Dont forget to close your cursor
db.close(); //AND your Database!
return hasObject;
}
Raw queries are more vulnerable to SQL Injection. I will suggest using query() method instead.
public boolean Exists(String searchItem) {
String[] columns = { COLUMN_NAME };
String selection = COLUMN_NAME + " =?";
String[] selectionArgs = { searchItem };
String limit = "1";
Cursor cursor = db.query(TABLE_NAME, columns, selection, selectionArgs, null, null, null, limit);
boolean exists = (cursor.getCount() > 0);
cursor.close();
return exists;
}
Source: here
SELECT EXISTS with LIMIT 1 is much faster.
Query Ex: SELECT EXISTS (SELECT * FROM table_name WHERE column='value' LIMIT 1);
Code Ex:
public boolean columnExists(String value) {
String sql = "SELECT EXISTS (SELECT * FROM table_name WHERE column='"+value+"' LIMIT 1)";
Cursor cursor = database.rawQuery(sql, null);
cursor.moveToFirst();
// cursor.getInt(0) is 1 if column with value exists
if (cursor.getInt(0) == 1) {
cursor.close();
return true;
} else {
cursor.close();
return false;
}
}
You can use SELECT EXISTS command and execute it for a cursor using a rawQuery,
from the documentation
The EXISTS operator always evaluates to one of the integer values 0
and 1. If executing the SELECT statement specified as the right-hand
operand of the EXISTS operator would return one or more rows, then the
EXISTS operator evaluates to 1. If executing the SELECT would return
no rows at all, then the EXISTS operator evaluates to 0.
I have tried all methods mentioned in this page, but only below method worked well for me.
Cursor c=db.rawQuery("SELECT * FROM user WHERE idno='"+txtID.getText()+"'", null);
if(c.moveToFirst())
{
showMessage("Error", "Record exist");
}
else
{
// Inserting record
}
One thing the top voted answer did not mention was that you need single quotes, 'like this', around your search value if it is a text value like so:
public boolean checkIfMyTitleExists(String title) {
String Query = "Select * from " + TABLE_NAME + " where " + COL1 + " = " + "'" + title + "'";
Cursor cursor = database.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursor.close();
return false;
}
cursor.close();
return true;
}
Otherwise, you will get a "SQL(query) error or missing database" error like I did without the single quotes around the title field.
If it is a numeric value, it does not need single quotes.
Refer to this SQL post for more details
SQLiteDatabase sqldb = MyProvider.db;
String Query = "Select * from " + TABLE_NAME ;
Cursor cursor = sqldb.rawQuery(Query, null);
cursor.moveToLast(); //if you not place this cursor.getCount() always give same integer (1) or current position of cursor.
if(cursor.getCount()<=0){
Log.v("tag","if 1 "+cursor.getCount());
return false;
}
Log.v("tag","2 else "+cursor.getCount());
return true;
if you not use cursor.moveToLast();
cursor.getCount() always give same integer (1) or current position of cursor.
Code :
private String[] allPushColumns = { MySQLiteHelper.COLUMN_PUSH_ID,
MySQLiteHelper.COLUMN_PUSH_TITLE, MySQLiteHelper.COLUMN_PUSH_CONTENT, MySQLiteHelper.COLUMN_PUSH_TIME,
MySQLiteHelper.COLUMN_PUSH_TYPE, MySQLiteHelper.COLUMN_PUSH_MSG_ID};
public boolean checkUniqueId(String msg_id){
Cursor cursor = database.query(MySQLiteHelper.TABLE_PUSH,
allPushColumns, MySQLiteHelper.COLUMN_PUSH_MSG_ID + "=?", new String [] { msg_id }, null, null, MySQLiteHelper.COLUMN_PUSH_ID +" DESC");
if(cursor.getCount() <= 0){
return false;
}
return true;
}
Here's a simple solution based on a combination of what dipali and Piyush Gupta posted:
public boolean dbHasData(String searchTable, String searchColumn, String searchKey) {
String query = "Select * from " + searchTable + " where " + searchColumn + " = ?";
return getReadableDatabase().rawQuery(query, new String[]{searchKey}).moveToFirst();
}
because of possible data leaks best solution via cursor:
Cursor cursor = null;
try {
cursor = .... some query (raw or not your choice)
return cursor.moveToNext();
} finally {
if (cursor != null) {
cursor.close();
}
}
1) From API KITKAT u can use resources try()
try (cursor = ...some query)
2) if u query against VARCHAR TYPE use '...' eg. COLUMN_NAME='string_to_search'
3) dont use moveToFirst() is used when you need to start iterating from beggining
4) avoid getCount() is expensive - it iterates over many records to count them. It doesn't return a stored variable. There may be some caching on a second call, but the first call doesn't know the answer until it is counted.
Try to use cursor.isNull method.
Example:
song.isFavorite = cursor.isNull(cursor.getColumnIndex("favorite"));
You can use like this:
String Query = "Select * from " + TABLE_NAME + " where " + Cust_id + " = " + cust_no;
Cursor cursorr = db.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursorr.close();
}
cursor.close();
private boolean checkDataExistOrNot(String columnName, String value) {
SQLiteDatabase sqLiteDatabase = getReadableDatabase();
String query = "SELECT * FROM" + TABLE_NAME + " WHERE " + columnName + " = " + value;
Cursor cursor = sqLiteDatabase.rawQuery(query, null);
if (cursor.getCount() <= 0) {
cursor.close();
return false; // return false if value not exists in database
}
cursor.close();
return true; // return true if value exists in database
}
I prefer to do it this way because it's fast and less expensive than other methods:
Cursor cursor = db.rawQuery("SELECT 1 FROM table WHERE condition = 1 LIMIT 1", null);
try {
if (cursor.moveToNext()) {
//Record exists
} else {
//Record doesn't exists
}
} finally {
cursor.close();
}
My version:
public boolean isTitleExists(String title, String type) {
int isExists = 0;
try {
String query = "SELECT EXISTS (SELECT 1 FROM titles WHERE title = ? and type = ?)";
PreparedStatement statement = connection.prepareStatement(query);
statement.setString(1, title);
statement.setString(2, type);
ResultSet rs = statement.executeQuery();
rs.next();
isExists = rs.getInt(1);
rs.close();
statement.close();
} catch (SQLException e) {
Common.console("isTitleExists error: " + e.getMessage());
}
return isExists == 1;
}
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();
}