I'm currently working on implementing a way to add, edit, update and delete information from my database through an interface within my Android Studio project, I currently have it adding correctly when it involves a table with no foreign key.
The issue I am having is when I try to add data to my database with a table that has a foreign key.
The method I would achieve this would be through imputing the relevant information as well as the ID of the foreign key. However, when doing this it will randomly change whatever ID I insert into ID : 2131165349. I am unsure where this ID comes from and this ID does not exist in the table where the foreign key originally is.
I believe my issue is in the code I have used to create the tables with reference to how I have created tables which have primary keys.
Below is my code for the onCreate method where this belongs.
public void onCreate(SQLiteDatabase sqLiteDatabase) {
String sqlBook = "CREATE TABLE book(id INTEGER PRIMARY KEY AUTOINCREMENT, bookName VARCHAR, bookAuthor VARCHAR);";
String sqlChapter = "CREATE TABLE chapter(id INTEGER PRIMARY KEY AUTOINCREMENT, chapterName VARCHAR, book_id INTEGER, FOREIGN KEY(book_id) REFERENCES book(id))";
String sqlSection ="CREATE TABLE section(id INTEGER PRIMARY KEY AUTOINCREMENT, sectionName VARCHAR, sectionInfo VARCHAR, book_id INTEGER, chapter_id INTEGER, FOREIGN KEY(book_id) REFERENCES book(id), FOREIGN KEY (chapter_id) REFERENCES chapter(id))";
sqLiteDatabase.execSQL(sqlBook);
sqLiteDatabase.execSQL(sqlChapter);
sqLiteDatabase.execSQL(sqlSection);
AddChapterActivity
public class AddChapterActivity extends AppCompatActivity {
DatabaseHelper db;
Button btnAddChapter, btnViewChapter, btnUpdateChapter, btnDeleteChapter;
EditText textEditChapterName, textEditBookID, textEditChapterID;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_chapter);
db = new DatabaseHelper(this);
btnAddChapter = findViewById(R.id.btnAddChapter);
btnViewChapter = findViewById(R.id.btnViewChapter);
btnUpdateChapter = findViewById(R.id.btnUpdateChapter);
btnDeleteChapter = findViewById(R.id.btnDeleteChapter);
textEditBookID = findViewById(R.id.textEditBookID);
textEditChapterName = findViewById(R.id.textEditChapterName);
textEditChapterID = findViewById(R.id.textEditChapterID);
addChapter();
}
public void addChapter(){
btnAddChapter.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String chapterName = textEditChapterName.getText().toString();
int book_id = textEditBookID.getId();
boolean insertChapter = db.addChapter(chapterName, book_id);
if(insertChapter == true) {
Toast.makeText(AddChapterActivity.this, "Chapter added successfully!", Toast.LENGTH_LONG).show();
}else{
Toast.makeText(AddChapterActivity.this, "Something went wrong.", Toast.LENGTH_LONG).show();
}
}
});
}
DatabaseHelper
public boolean addChapter(String chapterName, Integer book_id){
SQLiteDatabase db = getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("chapterName", chapterName);
contentValues.put("book_id", book_id);
long result = db.insert("chapter", null, contentValues);
if(result == -1) {
return false;
}else{
return true;
}
In the onClick()
method of the listener in AddChapterActivity
class, change this line:
int book_id = textEditBookID.getId();
with
int book_id = Integer.parseInt(textEditBookID.getText().toString());
You were getting the EditText
's id
and not the text with your code.
I guess (by its name) you have in textEditBookID
the id of the book, right?