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How to create two tables in one db file?

I want to create two tables in one db file, but it is not working as expected.
public class DBHelper extends SQLiteOpenHelper {
public static final String DBNAME = "Bocchi.db";
public DBHelper(Context context) {
super(context, "Bocchi.db", null, 1);
}
public static final String TABLE_NAME1 = "users";
public static final String TABLE_NAME2 = "breakfast";
#Override
public void onCreate(SQLiteDatabase MyDB) {
String table1 = "CREATE TABLE "+TABLE_NAME1+"(username TEXT PRIMARY KEY, password TEXT)";
String table2 = "CREATE TABLE "+TABLE_NAME2+"(username TEXT PRIMARY KEY, energy INT)";
MyDB.execSQL(table1);
MyDB.execSQL(table2);
}
Why am I doing like on video but it cannot create two tables. I have checked the db file, but it only has one table.

You can try the onUpgrade method like below
#Override
public void onUpgrade(SQLiteDatabase _db, int oldVer, int newVer){
onCreate(_db);
}

How to insert values with Foreign KEY in SQLite?

I am new with Android Sqlite Database.
I have created a database with SQLite in Android and I have a table Student_details which use a foreign key of the table: Student, I have made the id as AUTOINCREMENT.
And i tried to return the value of the AUTOINCREMENT Id from Student table.
But I am stuck to use the return values to insert into COLUMN_FR_KEY_USER_ID = "student_id"; as Foreign Key values.
How can I add value with a foreign key from another table using ContentValues into insetDataIntoStudentDetails method?
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "finalStudent.db";
private static final int VERSION_NUMBER = 16;
private static final String TABLE_STUDENT = "Student";
private static final String TABLE_DETAILS_NAME = "Student_details";
private static final String COLUMN_STUDENT_ID = "id";
private static final String COLUMN_DETAILS_ID = "id";
private static final String COLUMN_FR_KEY_USER_ID = "student_id";
private static final String COLUMN_STUDENT_NAME = "name";
private static final String COLUMN_DETAILS_NAME = "name";
private static final String COLUMN_STUDENT_EMAIL = "email";
private static final String COLUMN_STUDENT_PASSWORD = "password";
private static final String CREATE_STUDENT_TABLE = "CREATE TABLE "+TABLE_STUDENT+"( "+COLUMN_STUDENT_ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+COLUMN_STUDENT_NAME+" TEXT, "+COLUMN_STUDENT_EMAIL+" TEXT, "+COLUMN_STUDENT_PASSWORD+" TEXT)";
private static final String CREATE_DETAILS_TABLE = "CREATE TABLE "+TABLE_DETAILS_NAME+"( "+COLUMN_DETAILS_ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+COLUMN_DETAILS_NAME+" TEXT, "+COLUMN_FR_KEY_USER_ID+" INTEGER, FOREIGN KEY("+COLUMN_FR_KEY_USER_ID+") REFERENCES "+TABLE_STUDENT+" ("+COLUMN_STUDENT_ID+") ON UPDATE CASCADE ON DELETE CASCADE)";
private Context context;
private static final String DROP_TABLE = "DROP TABLE IF EXISTS "+TABLE_STUDENT;
private static final String DROP_DETAILS_TABLE = "DROP TABLE IF EXISTS "+TABLE_DETAILS_NAME;
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, VERSION_NUMBER);
this.context = context;
}
#Override
public void onCreate(SQLiteDatabase db) {
try {
Toast.makeText(context,"Table created successfully and called onCreate method",Toast.LENGTH_SHORT).show();
db.execSQL(CREATE_STUDENT_TABLE);
db.execSQL(CREATE_DETAILS_TABLE);
}catch (Exception e){
Toast.makeText(context,"Exception : "+e,Toast.LENGTH_SHORT).show();
}
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
try {
Toast.makeText(context,"Table created successfully and called onCreate method",Toast.LENGTH_SHORT).show();
db.execSQL(DROP_TABLE);
db.execSQL(DROP_DETAILS_TABLE);
onCreate(db);
}catch (Exception e){
Toast.makeText(context,"Exception : "+e,Toast.LENGTH_SHORT).show();
}
}
public long insertDataIntoStudent( String name, String email, String password){
// to write or read data in database , we have to call getWritableDatabase
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
// we have to call contentValues class to store data in the data
ContentValues contentValues = new ContentValues();
contentValues.put(COLUMN_STUDENT_NAME,name);
contentValues.put(COLUMN_STUDENT_EMAIL,email);
contentValues.put(COLUMN_STUDENT_PASSWORD,password);
// Insert the new row, returning the primary key value of the new row
long newRowId = sqLiteDatabase.insert(TABLE_STUDENT,null,contentValues);
return newRowId;
}
public void insetDataIntoStudentDetails(String name){
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
// TODO: insert the foreign key's value
contentValues.put(name,name);
}
#Override
public void onOpen(SQLiteDatabase db) {
super.onOpen(db);
//enable foreign key constraints like ON UPDATE CASCADE, ON DELETE CASCADE
db.execSQL("PRAGMA foreign_keys=ON;");
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
private final AppCompatActivity activity = MainActivity.this;
DatabaseHelper databaseHelper;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
databaseHelper = new DatabaseHelper(activity);
databaseHelper.insertDataIntoStudent("Bappy","abcd#gmail.com","145456");
}
}

I'll answer about databases in general, not specifically about Sqlite or it's usage in Android.
So you have student's name (which is not a primary key), but you need to save some additional data for this student to another table. The steps are:
Execute SELECT id FROM students WHERE name = ? to find the relevant identifier.
Execute INSERT INTO student_details for your secondary table using retrieved id as a key.
Extra tips:
Name is not a good unique identifier. It's good to have one more criteria - such as some group name, or group number or even date of birth.
When your database is large enough you may benefit from index for your search criteria to optimize execution of the first query. But usually it's not the case for client-side (in-app) databases.
Here we assume that name is not the data which could be updated by someone (or something) else between searching for id and executing INSERT. Otherwise it's wise to use transaction and "lock" your student until you complete the updates.

Column Constraint error using SQLITE on android

I'm trying to set up a database and name the columns respectively, but I'm getting an error on line 16 with the PRIMARY KEY saying "')' or coma expected got '_title'
public class MyDBHandler extends SQLiteOpenHelper{
private static final int DATABASE_VERSION=1;
private static final String DATABASE_NAME="movies.db";
public static final String TABLE_PRODUCTS="_movies";
public static final String COLUMN_ID="_id";
public static final String COLUMN_TITLE="_title";
public static final String COLUMN_DATERELEASED="_dateReleased";
public static final String COLUMN_FILENAME="_fileName";
public MyDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
}
#Override
public void onCreate(SQLiteDatabase db) {
//INFORMATION ABOUT EACH COLUMN FOR THE TABLE
String query="CREATE TABLE "+TABLE_PRODUCTS+"("+
COLUMN_ID+" INTEGER PRIMARY KEY AUTOINCREMENT "+
COLUMN_TITLE+" TEXT "+
COLUMN_DATERELEASED+"TEXT "+
COLUMN_FILENAME+" TEXT "
+" ); ";
db.execSQL(query);
}

Your query is wrong you forgot to set comma .
Your query is like this
#Override
public void onCreate(SQLiteDatabase db) {
//INFORMATION ABOUT EACH COLUMN FOR THE TABLE
String query="CREATE TABLE "+TABLE_PRODUCTS+"("+
COLUMN_ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+
COLUMN_TITLE+" TEXT, "+
COLUMN_DATERELEASED+"TEXT, "+
COLUMN_FILENAME+" TEXT "
+" ); ";
db.execSQL(query);
}

You forgot to add comma after each column. Your Query String should be
String query="CREATE TABLE "+TABLE_PRODUCTS+"("+
COLUMN_ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+
COLUMN_TITLE+" TEXT, "+
COLUMN_DATERELEASED+"TEXT, "+
COLUMN_FILENAME+" TEXT "
+" )";

Only allow unique data entry with Android SQLite?

Before I get into describing by problem I'd like to point out I am aware of the other threads asking this question, however none for me have been able to solve my issue.
I've been working on a sharing app using the BumpAPI, which upon receiving the chunk, saves it to an SQLite database for retrieval in a list view activity, this is all working fine and the data is saved, however if the same text is sent twice it will be saved again and again and the list view will show this, from what I've read I need the 'UNIQUE' identifier? however being completely new to SQL I am at a loss with regards to achieving this, here is my DataHelper class which im using to create and add the entries, would anyone be kind enough to modify it or inform me of a possible solution?
Thanks very much
public class DataHelper {
private static final String DATABASE_NAME = "tags.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_NAME = "TagTable";
private Context context;
private SQLiteDatabase db;
private SQLiteStatement insertStmt;
private static final String INSERT = "insert into "
+ TABLE_NAME + "(name) values (?)";
public DataHelper(Context context) {
this.context = context;
OpenHelper openHelper = new OpenHelper(this.context);
this.db = openHelper.getWritableDatabase();
this.insertStmt = this.db.compileStatement(INSERT);
}
public long insert(String name) {
this.insertStmt.bindString(1, name);
return this.insertStmt.executeInsert();
}
public void deleteAll() {
this.db.delete(TABLE_NAME, null, null);
}
public List<String> selectAll() {
List<String> list = new ArrayList<String>();
Cursor cursor = this.db.query(TABLE_NAME, new String[] { "name" },
null, null, null, null, "name desc");
if (cursor.moveToFirst()) {
do {
list.add(cursor.getString(0));
} while (cursor.moveToNext());
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
return list;
}
private static class OpenHelper extends SQLiteOpenHelper {
OpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_NAME + "(id INTEGER PRIMARY KEY, name TEXT)" + "text unique, " + "ON CONFLICT REPLACE");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
}
}

Add the unique keyword to the column.
db.execSQL("CREATE TABLE " + TABLE_NAME + "(id INTEGER PRIMARY KEY, name TEXT unique);

looks like you should first add unique index on Table Create statement
db.execSQL("CREATE TABLE " + TABLE_NAME + "(id INTEGER PRIMARY KEY, name TEXT)" + "**name** unique, " + "ON CONFLICT REPLACE");
it will prevent from having two entries with the same names
the second you could make select to check for existence of the data before making actually insert

Android Database SQLite Average

I am making an app for android with a SQLite Database that have only one table and two columns: one for names and the other for marks. Also, I can see the information of the database in a listview and I can add more elements to it. How can I make the average of the marks which are in the database? And how can I delete a row?
I paste my database helper
public class PersonDatabaseHelper {
private static final String TAG = PersonDatabaseHelper.class.getSimpleName();
// database configuration
// if you want the onUpgrade to run then change the database_version
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "mydatabase.db";
// table configuration
private static final String TABLE_NAME = "person_table"; // Table name
private static final String PERSON_TABLE_COLUMN_ID = "_id"; // a column named "_id" is required for cursor
private static final String PERSON_TABLE_COLUMN_NAME = "person_name";
private static final String PERSON_TABLE_COLUMN_PIN = "person_pin";
private DatabaseOpenHelper openHelper;
private SQLiteDatabase database;
// this is a wrapper class. that means, from outside world, anyone will communicate with PersonDatabaseHelper,
// but under the hood actually DatabaseOpenHelper class will perform database CRUD operations
public PersonDatabaseHelper(Context aContext) {
openHelper = new DatabaseOpenHelper(aContext);
database = openHelper.getWritableDatabase();
}
public void insertData (String aPersonName, String aPersonPin) {
// we are using ContentValues to avoid sql format errors
ContentValues contentValues = new ContentValues();
contentValues.put(PERSON_TABLE_COLUMN_NAME, aPersonName);
contentValues.put(PERSON_TABLE_COLUMN_PIN, aPersonPin);
database.insert(TABLE_NAME, null, contentValues);
}
public Cursor getAllData () {
String buildSQL = "SELECT * FROM " + TABLE_NAME;
Log.d(TAG, "getAllData SQL: " + buildSQL);
return database.rawQuery(buildSQL, null);
}
// this DatabaseOpenHelper class will actually be used to perform database related operation
private class DatabaseOpenHelper extends SQLiteOpenHelper {
public DatabaseOpenHelper(Context aContext) {
super(aContext, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
// Create your tables here
String buildSQL = "CREATE TABLE " + TABLE_NAME + "( " + PERSON_TABLE_COLUMN_ID + " INTEGER PRIMARY KEY, " +
PERSON_TABLE_COLUMN_NAME + " TEXT, " + PERSON_TABLE_COLUMN_PIN + " TEXT )";
Log.d(TAG, "onCreate SQL: " + buildSQL);
sqLiteDatabase.execSQL(buildSQL);
}
#Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
// Database schema upgrade code goes here
String buildSQL = "DROP TABLE IF EXISTS " + TABLE_NAME;
Log.d(TAG, "onUpgrade SQL: " + buildSQL);
sqLiteDatabase.execSQL(buildSQL); // drop previous table
onCreate(sqLiteDatabase); // create the table from the beginning
}
}
}

Use the avarage (avg) aggregate function:
String query = "SELECT AVG("+PERSON_TABLE_COLUMN_PIN +") FROM "+TABLE_NAME;
and then use SQLiteDatabase.rawQuery(String sql, String[] selectionArgs) for executing the query. Something like:
database.rawQuery(query, null);
Here you can find a sample fiddle.
While, for deleting a row, you can use SQLiteDatabase.delete(String table, String whereClause, String[] whereArgs). For example:
String where = PERSON_TABLE_COLUMN_ID+"=?";
String[] whereArgs = new String[]{String.valueOf(59)};
database.delete(TABLE_NAME, where, whereArgs);
the above code delete the row with id 59.