android-sqlite

问题 If I make any change to database like adding new column in my android application. and If I have already installed that on my phone. when I reinstall / update that application on mobile it doesn't update the database changes. My database code is : package com.screenmagic.smsmagicmobileapp; import java.text.SimpleDateFormat; import java.util.Date; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase;

问题 I have a column that is to be decremented by 1. The following code doesn't seem to be working. ContentValues dataToUpdate = new ContentValues(); dataToUpdate .put(MARKER_ID, MARKER_ID+"-1"); String where = IMAGE_ID_F+" = " +imageId+ " AND "+MARKER_ID+" > "+markerId+";"; int resultUpdate = db.update(TABLE_DEFECTS, dataToUpdate, where, null); I also tried rawQuery . That didn't work as well. MARKER_ID is the name of the column. String restructureDbQuesry="UPDATE "+TABLE_DEFECTS+" SET "+MARKER

问题 I have this problem. There are n tables created dynamically and each table has m columns, the columns could be repeated. This tables have in common 2 columns but there is no related data between them, for example: Table1 | A | B | Col1 | Col2 | Table2 | A | B | Col3 | Col4 | Table3 | A | B | Col1 | Col2 | Col4 | What I want to do is to merge all the tables into a big one like this: BigTable | A | B | Col1 | Col2 | Col3 | Col4 | And all the rows concatenated, for example if in table1 rows = 5,

问题 I have a class like this: public class DeliveryItem { private int _id; private String _invoiceNumber; private String _UPC_PLU; private String _vendorItemId; private int _packSize; private String _description; private BigDecimal _cost; private BigDecimal _margin; private BigDecimal _listPrice; private int _departmentNumber; private String _subdepartment; private String _quantity; public void setID(int id) { this._id = id; } public int getID() { return this._id; } . . . The cost, margin, and

问题 I am working on a login/register app just for training as I am a beginner everything is working except for a small problem but I don't know how to fix it , I tried searching but couldn't find anything here is the part of my database.kt fun userPresent (user: String,pass: String):Boolean { val db = writableDatabase val query = "select * from $TABLE_NAME where username = $user and password = $pass" val cursor = db.rawQuery(query,null) if (cursor.count <= 0) { cursor.close() return false }

问题 I have a big database which takes time to find needed information. So I decided to use RxJava to make this process asynchronous. @Override public void afterTextChanged(final Editable s) { final String query = s.toString(); Observable.create(new Observable.OnSubscribe<Cursor>() { @Override public void call(Subscriber<? super Cursor> subscriber) { subscriber.onNext(database.search(query)); } }).subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()).subscribe(new Subscriber

问题 I have implemented the SQliteOpenHelper with a Singleton pattern and it works fine till now. But consider the below sequence : A fragment starts a transaction to updating records A service gets triggered that reads the updated data Transaction fails for some reason and gets rolled back The service would have processed uncommitted data that got rolled back later. So it seems that a singleton pattern coupled with a service causes problems with data isolation. Yet i have read numerous posts

问题 I have a few doubts regarding SQLite DB status on uninstall of an Android application. What happens to SQLite DB when an app is uninstalled? How to seamlessly save SQlite DB on uninstalling of app if my device doesn't have an external store(SD card). recommended way to store information in DB / encrypt the DB such that it cant be accessed if user has root access to device 回答1: its a code to put database in internal storage public class DatabaseAdapter extends SQLiteOpenHelper { private static

问题 After countless hours of watching YouTube videos and tutorials, and reading up on info and advice, I've come to the conclusion that doing a bible app by using a SQLite database is the way to go. I've got no knowledge of coding whatsoever and just by taking bits and pieces of tutorial code and advice from someone I've got this far, so please be specific when answering. I've now created 3x tables. table_book, table_chapter, and table_verse. The tables are in one database. The database gets

问题 Here is the code example in which I got from https://www.ars.usda.gov/Services/docs.htm?docid=8964 . I have not found an example in which explains this type of code or how I would import it into SQLite database . After a little understanding of the code I should be able to work with it. Language java. ~01001~^~0100~^~Butter, salted~^~BUTTER,WITH SALT~^~~^~~^~Y~^~~^0^~~^6.38^4.27^8.79^3.87 ~01002~^~0100~^~Butter, whipped, with salt~^~BUTTER,WHIPPED,WITH SALT~^~~^~~^~Y~^~~^0^~~^6.38^4.27^8.79^3