Databases
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Postsdbo
PO
 

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  1. PO
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    <pre><code> public class Database { private static final String TAG = "DbAdapter"; private DatabaseHelper mDbHelper; private SQLiteDatabase mDb; public static final String TABLE_COMMENTS = "tablename"; public static final String COLUMN_ID = "_id"; public static final String COLUMN_COMMENT = "comment"; private static final String DATABASE_NAME = "databasename"; private static final int DATABASE_VERSION = 1; private final Context mCtx; private static class DatabaseHelper extends SQLiteOpenHelper { // Database creation sql statement private static final String DATABASE_CREATE = "CREATE TABLE tablename (id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL , column1 INTEGER, column2 TEXT, column3 TEXT, column4 TEXT, column5 TEXT, column6 NUMERIC)"; public DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase database) { database.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.w(DatabaseHelper.class.getName(), "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS " + TABLE_COMMENTS); onCreate(db); } } public Database(Context c) { this.mCtx = c; } public void open() throws SQLException { mDbHelper = new DatabaseHelper(mCtx); mDb = mDbHelper.getWritableDatabase(); } public void close() { mDbHelper.close(); } public void inset(ContentValues cv) { mDb.insert(TABLE_COMMENTS, null, cv); } public Cursor getdata() { Cursor c = mDb.rawQuery("SELECT * FROM tablename", null); return c; } public Cursor getById(int index) { Cursor c = mDb.rawQuery("SELECT * FROM tablename where field ="+index, null); return c; } public void deletedata(int index) { mDb.rawQuery("delete from tablename where id ="+index, null); } public boolean checkRegistration(String name) { Cursor c = mDb.rawQuery("SELECT * FROM tablename where column name= "+name, null); int count = c.getCount; c.close(); if(count &gt; 0) { return false; } else { return true; } } } Database db =new Database(this); db.open(); if(db.checkRegistration(str)) { //please register this user. } else { //this user already register } db.close(); </code></pre>
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    1. POChecking Names from Database
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    1. USiAndroid
    1. USiAndroid
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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      1. VTUpMod
    1. COBut, you type **c.getCount()** instead of **c.getCount**, which literary often used to described as method. the **mDb**, I think it came either from under parameter of **checkREgistration()** boolean method or as a field under **Database_Handler.java**. I'll keep that as a reference as well.
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      1. USDavid Dimalanta
    2. COThere is a bit of force close error when running. I'm not sure if I did it right. I typed it on what you said at **Database_Handler.java** and when I fixed it on **onClick()** method under **from_3_players.java**, something went wrong. Here's my code and tell me if I'm wrong. Here's my code under **onClick()**: if(db.checkRegistration(label, null)) { Toast.makeText(getApplicationContext(), "Name existed.", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(getApplicationContext(), "Name available!", Toast.LENGTH_SHORT).show(); }
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      1. USDavid Dimalanta
    3. COare your pass parameter as string?
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Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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