android - .SQLiteConstraintException : tabtest. id may not be NULL 的解释

Question

有人可以为我解释以下问题吗？这是下表创建注意 id 是 null

   db.execSQL(
              "create table tabtest " +
              "(id integer null, name text, timage blob )"
              );

如果id为null，下面的语句会报错

 contact.setID(Integer.parseInt(cursor.getString(0)));

错误

05-28 22:03:10.826: E/SQLiteDatabase(1861): android.database.sqlite.SQLiteConstraintException: tabtest.id may not be NULL (code 19)

为什么 parsetInt 的 id 不应该为空？

这是下面的方法..如果您需要其他任何东西，请问我。

     public List<Contact> getAllContacts() {
         List<Contact> contactList = new ArrayList<Contact>();
         // Select All Query
         String selectQuery = "SELECT * FROM tabtest ORDER BY name";

         SQLiteDatabase db = this.getWritableDatabase();
         db.execSQL("drop table tabtest");
         db.execSQL(
                  "create table tabtest " +
                  "(id integer not null, name text, timage blob )"
                  );
         Cursor cursor = db.rawQuery(selectQuery, null);
         // looping through all rows and adding to list
         if (cursor.moveToFirst()) {
         do {
         Contact contact = new Contact();
         contact.setID(Integer.parseInt(cursor.getString(0)));
         contact.setName(cursor.getString(1));
         contact.setImage(cursor.getBlob(2));
         // Adding contact to list
         System.out.println (contact);
         contactList.add(contact);
         } while (cursor.moveToNext());
         }

db.close();
// return contact list
return contactList;

     }

Answer 1

documentation状态:

The result and whether this method throws an exception when the column value is null or the column type is not a string type is implementation-defined.

可以肯定的是，手动检查该特定列的值是否为空:

if (cursor.isNull(0)) {
    contact.setID(null);
} else {
    contact.setID(Integer.parseInt(cursor.getString(0)));
}