I am trying to get the last inserted rowid from a sqlite database in Android. I have read a lot of posts about it, but can't get one to work.
This is my method:
public Cursor getLastId() {
return mDb.query(DATABASE_TABLE, new String[] {KEY_WID}, KEY_WID + "=" + MAX(_id), null, null, null, null, null);}
I have tried with MAX, but I must be using it wrong. Is there another way?
Well actually the SQLiteDatabase class has its own insert method which returns the id of the newly created row. I think this is the best way to get the new ID.
You can check its documentation here.
I hope this helps.
Use
SELECT last_insert_rowid();
to get the last inserted rowid.
If you are using AUTOINCREMENT keyword then
SELECT * from SQLITE_SEQUENCE;
will tell you the values for every table.
To get the last row from the table..
Cursor cursor = theDatabase.query(DATABASE_TABLE, columns,null, null, null, null, null);
cursor.moveToLast();
Use moveToLast() in Cursor interface.
From android.googlesource.com
/**
* Move the cursor to the last row.
*
* <p>This method will return false if the cursor is empty.
*
* #return whether the move succeeded.
*/
boolean moveToLast();
Simple example:
final static String TABLE_NAME = "table_name";
String name;
int id;
//....
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
if(cursor.moveToLast()){
//name = cursor.getString(column_index);//to get other values
id = cursor.getInt(0);//to get id, 0 is the column index
}
Or you can get the last row when insertion(Which is #GorgiRankovski have mentioned):
long row = 0;//to get last row
//.....
SQLiteDatabase db= this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COLUMN_NAME, name);
row = db.insert(TABLE_NAME, null, contentValues);
//insert() returns the row ID of the newly inserted row, or -1 if an error occurred
Also their is a multiple ways you can do this using query:
One is expressed by #DiegoTorresMilano
SELECT MAX(id) FROM table_name. or to get all columns values SELECT * FROM table_name WHERE id = (SELECT MAX(id) FROM table_name).
If your PRiMARY KEY have sat to AUTOINCREMENT, you can SELECT vaules occording to max to min and limit the rows to 1 using SELECT id FROM table ORDER BY column DESC LIMIT 1
(If you want each and every value, use * instead of id)
If you want the last_insert_id just afert a insert you can use that :
public long insert(String table, String[] fields, String[] vals )
{
String nullColumnHack = null;
ContentValues values = new ContentValues();
for (int i = 0; i < fields.length; i++)
{
values.put(fields[i], vals[i]);
}
return myDataBase.insert(table, nullColumnHack, values);
}
The insert method returns the id of row just inserted or -1 if there was an error during insertion.
long id = db.insert("your insertion statement");
db is an instance of your SQLiteDatabase.
Try this:
public Cursor getLastId() {
return mDb.query(DATABASE_TABLE, new String[] { **MAX(id)** }, null, null, null, null, null, null);}
/**
* #return
*/
public long getLastInsertId() {
long index = 0;
SQLiteDatabase sdb = getReadableDatabase();
Cursor cursor = sdb.query(
"sqlite_sequence",
new String[]{"seq"},
"name = ?",
new String[]{TABLENAME},
null,
null,
null,
null
);
if (cursor.moveToFirst()) {
index = cursor.getLong(cursor.getColumnIndex("seq"));
}
cursor.close();
return index;
}
I use this
public int lastId(){
SQLiteDatabase db =
this.getReadableDatabase();
Cursor res = db.rawQuery( "select * from resep", null );
res.moveToLast();
return res.getInt(0);
}
In your DbHelper class,
public long getLastIdFromMyTable()
{
SQLiteDatabase db = this.getReadableDatabase();
SQLiteStatement st = db.compileStatement("SELECT last_insert_rowid() from " + MY_TABLE);
return st.simpleQueryForLong();
}
Related
I want to get the first name, middle name and last name of a student whose userid is used for login. I have written this particular piece of code but it stops my application.
I have used both the ways like database.query() and .rawquery() also.
Cursor studentData(String userId) {
SQLiteDatabase db = getWritableDatabase();
Cursor cursor = db.query(studentTable, new String[] { "First_Name", "Middle_Name", "Last_Name"}, "User_ID=?", new String[] { userId }, null, null, null, null);
// Cursor cursor = db.rawQuery("select First_Name, Middle_Name, Last_Name from Student_Table where User_ID =?", new String[]{userId});
String data = cursor.getString(cursor.getColumnIndex("First_Name"));
db.close();
return cursor;
}
I should get whole name in the string.
You have a number of issues.
Attempting to use String data = cursor.getString(cursor.getColumnIndex("First_Name"));,
will result in an error because you have not moved the cursor beyond BEFORE THE FIRST ROW and the attempt to access the row -1 will result in an exception (the likely issue you have encountered).
you can use various move??? methods e.g. moveToFirst, moveToNext (the 2 most common), moveToLast, moveToPosition.
Most of the Cursor move??? methods return true if the move could be made, else false.
You CANNOT close the database and then access the Cursor (this would happen if the issue above was resolved)
The Cursor buffers rows and then ONLY when required.
That is The Cursor is when returned from the query method (or rawQuery) at a position of BEFORE THE FIRST ROW (-1), it's only when an attempt is made to move through the Cursor that the CursorWindow (the buffer) is filled (getCount() included) and the actual data obtained. So the database MUST be open.
If you want a single String, the full name, then you could use :-
String studentData(String userId) { //<<<<<<<<<< returns the string rather than the Cursor
SQLiteDatabase db = getWritableDatabase();
String rv = "NO NAME FOUND"; //<<<<<<<<<< value returned if no row is located
Cursor cursor = db.query(studentTable, new String[] { "First_Name", "Middle_Name", "Last_Name"}, "User_ID=?", new String[] { userId }, null, null, null, null);
if (cursor.modeToFirst()) {
String rv =
cursor.getString(cursor.getColumnIndex("First_Name")) +
" " +
cursor.getString(cursor.getColumnIndex("Middle_Name")) +
" " +
cursor.getString(cursor.getColumnIndex("Last_Name"));
}
cursor.close(); //<<<<<<<<<< should close all cursors when done with them
db.close(); //<<<<<<<<<< not required but would result in an exception if returning a Cursor
return rv;
}
Or alternately :-
String studentData(String userId) { //<<<<<<<<<< returns the string rather than the Cursor
SQLiteDatabase db = getWritableDatabase();
String rv = "NO NAME FOUND"; //<<<<<<<<<< value returned if no row is located
Cursor cursor = db.query(studentTable, new String[] { "First_Name"||" "||"Middle_Name"||" "||"Last_Name" AS fullname}, "User_ID=?", new String[] { userId }, null, null, null, null);
if (cursor.modeToFirst()) {
String rv =
cursor.getString(cursor.getColumnIndex("fullname"));
}
cursor.close(); //<<<<<<<<<< should close all cursors when done with them
db.close(); //<<<<<<<<<< not required but would result in an exception if returning a Cursor
return rv;
}
the underlying query being SELECT First_Name||" "||Middle_Name||" "||LastName AS fullname FROM student_table; so you concatenate the names as part of the query which returns just one dynamically created column named fullname.
I am developing an application where the user inputs title and the date. I want to prevent the duplicated titles being inputted on the same day in to database. I am checking if the title exists on the selected date. However my query seems not to work and i don't know why, the application just crashes.Is this query correct? Can someone help?
public boolean checkExist(String title, String date) {
SQLiteDatabase db = this.getWritableDatabase();
Cursor c = db.rawQuery("SELECT * FROM "+TABLE_NAME+" WHERE "+TITLE+"=?" +"AND" + DATE+"=?", new String[] {title,date});
boolean exists = c.moveToFirst();
c.close();
return exists;
}
One issue that you have is that c.moveToFirst will always fail if a match does not exist as you are trying to move to a row in an empty cursor.
The resolution is to not use c.moveToFirst and instead get the count of the rows and then set the return value accordingly.
e.g.
public boolean checkExist(String title, String date) {
SQLiteDatabase db = this.getWritableDatabase();
Cursor c = db.rawQuery("SELECT * FROM "+TABLE_NAME+" WHERE "+TITLE+"=?" +"AND" + DATE+"=?", new String[] {title,date});
boolean exists = c.getCount() > 0;
c.close();
return exists;
}
The second issue is that the query itself is wrong as you do not have spaces either side of the AND keyword. That is instead of
Cursor c = db.rawQuery("SELECT * FROM "+TABLE_NAME+" WHERE "+TITLE+"=?" +"AND" + DATE+"=?", new String[] {title,date});
You should have
Cursor c = db.rawQuery("SELECT * FROM "+TABLE_NAME+" WHERE "+TITLE+"=?" +" AND " + DATE+"=?", new String[] {title,date});
Personally, I setup constants for SQL keywords that include the space and then use these. So I'd have something along the lines of +TITLE+"=?" + SQLAND + DATE+"=?". Where SQLAND would be defined along the lines of String SQLAND=" AND ";
PS look at Cricket_007's answer, the code is neater/better it's easier to read.
Your spacing is off. TITLE+"=?" +"AND" + DATE becomes TITLE=?ANDDATE=?
I would suggest this. See DatabaseUtils.queryNumEntries
public boolean checkExist(String title, String date) {
SQLiteDatabase db = getReadableDatabase();
String[] args = new String[] {title,date};
String filter = String.format("%s=? AND %s=?", TITLE, DATE);
return DatabaseUtils.queryNumEntries(db, TABLE_NAME, filter, args) > 0;
}
you should be using c.getCount() instead of c.moveToFirst()
if the value is greater than 0, then it exists
is there a way to change my function:
public categorie createCategoria(String categoria) {
ContentValues values = new ContentValues();
values.put(MySQLiteHelper.COLUMN_NOME, categoria);
values.put(MySQLiteHelper.COLUMN_PREF, 0);
long insertId = database.insert(MySQLiteHelper.TABLE_CATEGORIE, null,
values);
Cursor cursor = database.query(MySQLiteHelper.TABLE_CATEGORIE,
allCategorieColumns, MySQLiteHelper.COLUMN_ID + " = " + insertId, null,
null, null, null);
cursor.moveToFirst();
categorie newCategoria = cursorToCategorie(cursor);
cursor.close();
return newCategoria;
}
this is a raw insert, i would like to change this function to make it update or insert accordingly. i would like to change this becouse i'm already using this function in some places, but now i need to choose if insert a row or update (or ignoring the insert) a row with the same COLUMN_NOME. can someone help me doing this?
i mean i would like to insert a new row ONLY if there isn't another with the same name (as usual you know).
You can use insertWithOnConflict() if you want to insert or update, depending in whether the record exists or not:
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COLUMN_ID, id);
contentValues.put(COLUMN_VALUE, value);
// this will insert if record is new, update otherwise
db.insertWithOnConflict(TABLE, null, contentValues, SQLiteDatabase.CONFLICT_REPLACE);
you could call int nRowsEffected = database.update(...); if there are no rows effected by the update either the row doesn't exist (or you hosed your update()!) therefore you need to call database.insert(...). of course if nRowsEffected > 0 then you are done.
You can use execSQL and use INSERT OR REPLACE
String[] args = {"1", "newOrOldCategory"}; // where 1 is the category id
getWritableDatabase().execSQL("INSERT OR REPLACE INTO table_name (idColoumn, categoryColumn) VALUES (?, ?)", args);
First of all you have write function which is check whether id is exists in particular Table like:
/**
* #param table_name
* #param server_id
* #return
*/
public boolean isServerIdExist(String table_name, int server_id) {
long line = DatabaseUtils.longForQuery(mDB, "SELECT COUNT(*) FROM " + table_name + " WHERE id=?",
new String[]{Integer.toString(server_id)});
return line > 0;
}
You have to pass table_name and id in that like
/**
* INSERT in TABLE_ACCOUNT_DEVICE
**/
public long insertOrUpdateAccountDevice(int server_id, int account_id,
String device_name, String device_id,
String last_active, String itp,
String utp, int status) {
ContentValues values = new ContentValues();
values.put(ACCOUNT_DEVICE_ACCOUNT_ID, account_id);
values.put(ACCOUNT_DEVICE_DEVICE_NAME, device_name);
values.put(ACCOUNT_DEVICE_DEVICE_ID, device_id);
values.put(ACCOUNT_DEVICE_LAST_ACTIVE, last_active);
values.put(ACCOUNT_DEVICE_ITP, itp);
values.put(ACCOUNT_DEVICE_UTP, utp);
values.put(ACCOUNT_DEVICE_STATUS, status); // 0=pending, 1=active, 2=Inactive, -1=not_found
/**
* isServerIdExists
*/
if (isServerIdExists(TABLE_ACCOUNT_DEVICE, server_id)) {
values.put(ACCOUNT_DEVICE_SERVER_ID, server_id);
return mDB.insert(TABLE_ACCOUNT_DEVICE, null, values);
} else {
return mDB.update(TABLE_ACCOUNT_DEVICE, values, ACCOUNT_DEVICE_SERVER_ID + " =? ",
new String[]{Integer.toString(server_id)});
}
}
Hope it will helps you.
I'm trying a simple SQL Command wihtin my Android-App, to get the age of a selected Person:
public int getAge(){
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM persons WHERE name =? " + MainActivity.selectedPerson.getText().toString(), null);
int age = cursor.getInt(3); // column with ages
cursor.close();
db.close();
return age;
}
But when I run my app, it crashes when I call the function getAge(). I get the following Error:
SQLiteException: no such column: Max: , while compiling: SELECT * FROM persons WHERE name = Max
I don't get it. There is the name "Max" in the table. What am I doing wrong? Thanks in advance.
Edit 2:
With this one:
Cursor cursor = db.rawQuery("SELECT name FROM persons WHERE name = '" + MainActivity.selectedPerson.getText().toString() + "'", null);
I get a different error:
08-27 19:43:47.573: E/AndroidRuntime(6161): android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 1
what does this mean?
You should consider using the selectionArgs parameter of rawQuery() to prevent SQL Injection Attacks:
Cursor cursor = db.rawQuery("SELECT * FROM persons WHERE name = ?", new String[] { MainActivity.selectedPerson.getText().toString() });
Also you only need one column so rather than wasting resources by selecting them all with *, you should just select the one column:
Cursor cursor = db.rawQuery("SELECT age FROM persons WHERE name = ?", new String[] { MainActivity.selectedPerson.getText().toString() });
Hope that helps!
All together it should look like:
public int getAge(){
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT age FROM persons WHERE name = ?", new String[] { MainActivity.selectedPerson.getText().toString() });
int age;
// Check if you have a valid result and move to the first row to read it
if(cursor.moveToFirst())
age = cursor.getInt(0);
// Prevent a crash if there is no data for this name
else
age = 0;
cursor.close();
db.close();
return age;
}
Chan ge the 3rd line of your program:
Cursor cursor = db.rawQuery("SELECT * FROM persons WHERE name =? " + MainActivity.selectedPerson.getText().toString(), null);
to this:
Cursor cursor = db.rawQuery("SELECT * FROM persons WHERE name = ?", new String[] { MainActivity.selectedPerson.getText().toString()} );
Try this:
public int getAge(){
int age;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM persons WHERE name = '" + MainActivity.selectedPerson.getText().toString()+"'",null);
if(cursor.moveToFirst())
{
age = cursor.getInt(3); // column with ages
}
cursor.close();
db.close();
return age;
}
You missed the single quotes (' ') in your sql command. That's why MAX was taken as a column and not as a value.
Using the typical SQLiteDatabase object in Android's API, what can I do to get the next AUTO_INCREMENT value of a particular column (ie. id) without affecting the value itself. Is there a method for that? Or what query should I execute to get that result. Keep in mind that SQLiteDatabase.query() returns a Cursor object, so I'm not too sure how to deal with that directly if I just want to get a value out of it.
You're right. The first answer (still below) only works without an AUTOINCREMENT for id. With AUTOINCREMENT, the values are stored in a separate table and used for the increment. Here's an example of finding the value:
public void printAutoIncrements(){
String query = "SELECT * FROM SQLITE_SEQUENCE";
Cursor cursor = mDb.rawQuery(query, null);
if (cursor.moveToFirst()){
do{
System.out.println("tableName: " +cursor.getString(cursor.getColumnIndex("name")));
System.out.println("autoInc: " + cursor.getString(cursor.getColumnIndex("seq")));
}while (cursor.moveToNext());
}
cursor.close();
}
See: http://www.sqlite.org/autoinc.html
First Answer:
You can query for the max of the _id column, such as:
String query = "SELECT MAX(id) AS max_id FROM mytable";
Cursor cursor = db.rawQuery(query, null);
int id = 0;
if (cursor.moveToFirst())
{
do
{
id = cursor.getInt(0);
} while(cursor.moveToNext());
}
return id;
This works for row ids that haven't been specified as "INTEGER PRIMARY KEY AUTOINCREMENT" (all tables have a row id column).
This is the best way to get the last ID on auto increment PRIMARY KEY with SQLITE
String query = "select seq from sqlite_sequence WHERE name = 'Table_Name'"
An important remark about the SQLITE_SEQUENCE table.
The documentation says
The SQLITE_SEQUENCE table is created and initialized automatically whenever a normal table that contains an AUTOINCREMENT column is created.
So the SQLITE_SEQUENCE table is created, but NOT the row associated with the table that contains the AUTOINCREMENT column. That row is created with the first insert query (with "seq" value of 1).
That means that you must doing at least one insert operation before looking for the next autoincrement value of a specific table. It could be done for example just after the creation of the table, performing an insert and a delete of a dummy row.
Here is what I use to get the next AUTOINCREMENT value for a specific table:
/**
* Query sqlite_sequence table and search for the AUTOINCREMENT value for <code>tableName</code>
* #param tableName The table name with which the AUTOINCREMENT value is associated.
*
* #return The next AUTOINCREMENT value for <code>tableName</code>
* If an INSERT call was not previously executed on <code>tableName</code>, the value 1 will
* be returned. Otherwise, the returned value will be the next AUTOINCREMENT.
*/
private long getNextAutoIncrement(String tableName) {
/*
* From the docs:
* SQLite keeps track of the largest ROWID using an internal table named "sqlite_sequence".
* The sqlite_sequence table is created and initialized automatically
* whenever a normal table that contains an AUTOINCREMENT column is created.
*/
String sqliteSequenceTableName = "sqlite_sequence";
/*
* Relevant columns to retrieve from <code>sqliteSequenceTableName</code>
*/
String[] columns = {"seq"};
String selection = "name=?";
String[] selectionArgs = { tableName };
Cursor cursor = mWritableDB.query(sqliteSequenceTableName,
columns, selection, selectionArgs, null, null, null);
long autoIncrement = 0;
if (cursor.moveToFirst()) {
int indexSeq = cursor.getColumnIndex(columns[0]);
autoIncrement = cursor.getLong(indexSeq);
}
cursor.close();
return autoIncrement + 1;
}
Inside the SQLiteOpenHelper you use, start a transaction. Insert some data and then rollback.
Such a way, you 'll be able to get the next row id, like this:
public long nextId() {
long rowId = -1;
SQLiteDatabase db = getWritableDatabase();
db.beginTransaction();
try {
ContentValues values = new ContentValues();
// fill values ...
// insert a valid row into your table
rowId = db.insert(TABLE_NAME, null, values);
// NOTE: we don't call db.setTransactionSuccessful()
// so as to rollback and cancel the last changes
} finally {
db.endTransaction();
}
return rowId;
}
It's work.
public static long getNextId(SQLiteDatabase db, String tableName) {
Cursor c = null;
long seq = 0;
try {
String sql = "select seq from sqlite_sequence where name=?";
c = db.rawQuery(sql, new String[] {tableName});
if (c.moveToFirst()) {
seq = c.getLong(0);
}
} finally {
if (c != null) {
c.close();
}
}
return seq + 1;
}
You can use cursor.getInt(i); method
i here is index of the id column
Cursor c = db.rawQuery("Select * From mSignUp", null);
String mail = null;
try {
while (c.moveToNext()) {
mail = c.getString(0);
String pas = c.getString(1);
Toast.makeText(getApplicationContext(), "Name = " + mail + " Pass = " + pas, Toast.LENGTH_SHORT).show();
}
}catch (CursorIndexOutOfBoundsException e){
Log.e("OutOfBound", Log.getStackTraceString(e));
}
finally {
c.close();
}