SQLite更新/替换表Android

Question

I have an app that gets JSON data from a server. I then put the parsed data into the android SQLite database and use the data as needed. This all works great, however, I am unable to find a method to update the whole table. The scenario would be that this Json Data feed gets updated every week on the server. I have two Questions:

What am I missing or what is the method for updating the SQLite table? (currently this just duplicates the data)

public void updateTable(Product product){
    SQLiteDatabase db = this.getWritableDatabase();
    try{
        ContentValues values = new ContentValues();
    values.put(KEY_TYPE_NAME, product.getmProductTypeName());
    // more columns here...
    db.update(TABLE_NAME, values, null,null);
    db.close();
    }catch(Exception e){
    Log.e("error:",e + "in updateData method")
    }

What is an ideal system for updating the data? Would it be silly and bad practice to just call the method when connected to internet?

Related Code in "Main Activity":

    handler = new DBHandler(this);
    NetworkUtils utils = new NetworkUtils(MainActivity.this);
    if (handler.getProductCount() == 0 && utils.isConnectingToInternet()) {
        new JsonDataParse().execute();
    }`

Related Code "DBhandler" Activity:

    public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL(DROP_TABLE);
    onCreate(db);
}

String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + "(" + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_TYPE_NAME + " TEXT" + ")"

That is basically my CREATE TABLE String format. I just condensed to because it has 16 columns.

This is the code I added to only delete the stored data only if there was data:

        if(handler.getProductCount() == 0) {

              }else{
                handler.deleteData();
            }

Then I just just added the delete the method as suggested:

    public void deleteData() {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(TABLE_NAME, "1", null);
}

Answer 1

I'm not sure what you mean by "update the whole table". It sounds to me like you just need to delete the data in the table and then use your current method to add the new data. To delete the contents you can use:

db.delete(TABLE_NAME, "1", null);

Then call your existing method to re-populate the table from the server.

What is an ideal system for updating the data? Would it be silly and bad practice to just call the method when connected to internet?

No it wouldn't be bad practice. That makes sense, as you'll only be able to reach the server if you're connected to the internet anyway.