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android sqlite common question increment a column value return all columns of a table add a column to a table

admin 11月 11, 2020 0

public String getEmployeeName(String empNo) {
    Cursor cursor = null;
    String empName = "";
    try {
        cursor = SQLiteDatabaseInstance_.rawQuery("SELECT EmployeeName FROM Employee WHERE EmpNo=?", new String[] {empNo + ""});
        if(cursor.getCount() > 0) {
            cursor.moveToFirst();
            empName = cursor.getString(cursor.getColumnIndex("EmployeeName"));
        }
        return empName;
    }finally {
        cursor.close();
    }
}

increment a column value

//UPDATE {Table} SET {Column} = {Column} + {Value} WHERE {Condition}
UPDATE Products SET Price = Price + 1 WHERE ProductID = 50

return all columns of a table

SQLiteDatabase mDataBase;
(some code here...)
mDataBase = getReadableDatabase();
Cursor dbCursor = mDataBase.query(TABLE_NAME, null, null, null, null, null, null);
String[] columnNames = dbCursor.getColumnNames();

add a column to a table

The simple way is uninstalling the application. It will delete the old database. The other way you can override the onUpgrade function. Go to the page stackoverflow adding-a-new-column-in-sqlite-database to see the detail steps.