如何在SQLite Android中更新表

Question

In my app i want to update my database table based on two column.Means update salary where firstname="ekant" and last name="kancha" .So can any body plz tell me what will be the query i have to write.

public int updateStatus(int salary,String fname,String lName)
{
    ContentValues cv=new ContentValues();

    String where = fname+ "=" + "ekanta";
    cv.put("salary",salary);
    return sdb.update(DATABASE_TABLENAME, cv, where, null);

}

this code works only when i want to update based on first name..But i want to update based on firstname and lastname.

plz help me.thanx

Answer 1

Use placeholders . This makes it easier to read the SQL query and protects against SQL Injection (accidental or otherwise).

public int updateSalary (int salary, String fname, String lName)
{
    ContentValues cv = new ContentValues();
    cv.put("salary", salary);

                 /* use COLUMN NAMES here */                     
    String where = "firstname = ? and lastname = ?";
                 /* bind VALUES here */
    String[] whereArgs = new { fname, lname };
    return sdb.update(DATABASE_TABLENAME, cv, where, whereArgs);
}

If you have constants (eg private final static COLUMN_FNAME = "firstname" ) for the COLUMN NAMES, then you can build where using these constants.

However, do not put VALUES in the where string. Instead, use ? and supply any VALUES via the whereArgs array as per the above example.

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Also, it is possible for people (even within the same organization) to share the same first name and last name. Basing the database queries/updates around such a pairing will break in such cases so it may be prudent to work on designing the API to work with a better record identifier.

Answer 2

用这个...

 String where = fname+ "=" + "ekanta" + " and " + lname + "=" + "your lastname";