Basic troubles with SQLite databases. Notepad tutorial of android

Question

This is a very basic question. I am just trying to understand how SQLite database works. So, here's what I do: In the code section below which is taken from notepad tutorial 3rd exercise, I change KEY_TITLE to KEY_NAME and all place I find title to name. And the application crashes. Why does this happen?

public static final String KEY_TITLE = "title";
//change to:     public static final String KEY_NAME = "name";
public static final String KEY_BODY = "body";
public static final String KEY_ROWID = "_id";

private static final String TAG = "NotesDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;

/**
 * Database creation sql statement
 */
private static final String DATABASE_CREATE =
    "create table notes (_id integer primary key autoincrement, "
    + "title text not null, body text not null);";

/*change to: private static final String DATABASE_CREATE = "create table notes (_id integer primary key autoincrement, " + "name text not null, body text not null);"; */

Are you getting any errors in the logs? Any errors from the program before it crashes? — ipd

John O'Connor John O'Connor · Accepted Answer · 2011-07-15T01:08:16

It would be helpful if you copied the stack trace (using logcat / DDMS) or copied your entire SQLiteDBAdapter, but just looking at what you posted, you definitely have a problem in that you're using the wrong field name in the sqlite database create statement.

The "title" field should be renamed "name" to match your changed column name.

Change:

private static final String DATABASE_CREATE =
"create table notes (_id integer primary key autoincrement, "
+ "title text not null, body text not null);";

To

private static final String DATABASE_CREATE =
"create table notes (_id integer primary key autoincrement, "
+ "name text not null, body text not null);";

I also tend to just use the statics themselves in the create statement, so it could be written like the following:

    private static final String DATABASE_CREATE =
"create table notes (" + KEY_ROWID + " integer primary key autoincrement, "
+ KEY_NAME + " text not null, " + KEY_BODY + " text not null);";

Then you could change the names often and not encounter database create breakage.

Basic troubles with SQLite databases. Notepad tutorial of android

2 Answers