android-sqlite

问题 This question was migrated from Android Enthusiasts Stack Exchange because it can be answered on Stack Overflow. Migrated 6 years ago . I tried to create an SQLite database and do some stuff with it. But I found that my onCreate method is not even invoked!! I am sending a message to LogCat on the begining of the onCreate method. My assumption is, the (super) constructor will invoke onCreate method. Is that right? My Code: import android.database.sqlite.SQLiteOpenHelper; import android

问题 I know this has been asked a couple of times before, but in all those questions neither the OP's nor the people who answered, provided clear examples. So what I'm trying to ask here is if having a class like this public class MyDatabaseDB { // database constants public static final String DB_NAME = "mydatabase.db"; public static final int DB_VERSION = 1; // list table constants public static final String LIST_TABLE = "list"; public static final String LIST_ID = "_id"; public static final int

问题 I have been doing some experiments to measure sqlite performance on android. I was disappointed a little bit with the results. What i did was inserting 10.000 queries to table and it took 130-140 seconds but with these conditions ; 1. Samsung galaxy s3 in power saving mode 2. Inserted data(or class)has 3 strings and one float(real for sqlite) 3. Insert event is being done in asynctask. 4. In asynctask, i am showing a progress dialog with passed timer text in it (System.currentTimeMillis -

问题 as can be seen in the documentation the syntax to make insert or update is : INSERT OR REPLACE INTO <table> (<columns>) VALUES (<values>) , my question is there any function that merge the following ? public long insert (String table, String nullColumnHack, ContentValues values) public int update (String table, ContentValues values, String whereClause, String[] whereArgs) or it has to be done with a prepared SQL statement and rawQuery? What's the best practices to do an insert or update in

问题 How can I create a list Array (the list display First Alphabet when scroll) with the cursor data? 回答1: Go through every element in the Cursor , and add them one by one to the ArrayList . ArrayList<WhateverTypeYouWant> mArrayList = new ArrayList<WhateverTypeYouWant>(); for(mCursor.moveToFirst(); !mCursor.isAfterLast(); mCursor.moveToNext()) { // The Cursor is now set to the right position mArrayList.add(mCursor.getWhateverTypeYouWant(WHATEVER_COLUMN_INDEX_YOU_WANT)); } (replace

问题 I want to change the sqlite database .db file to excel. But I am not able to find what exactly I have to do. Can anybody please elaborate in a simple way what I have to perform to achieve this task. By searching on Google, so many links appears, but I am not able to understand the step by step way to do this. I have followed these links: 1. How to convert excel sheet into database of sqlite in android 2. SQlite database programmatically convert into Excel file format in Android 3. http:/

问题 Every record in my SQLite database contains a field which contains a Date stored as a string in the format 'yyyy-MM-dd HH:mm:ss' . Is it possible to query the database to get the record which contains the most recent date please? 回答1: you can do it like this SELECT * FROM Table ORDER BY date(dateColumn) DESC Limit 1 回答2: For me I had my query this way to solve my problem select * from Table order by datetime(datetimeColumn) DESC LIMIT 1 Since I was storing it as datetime not date column 回答3:

问题 I am trying to use this query upon my Android database, but it does not return any data. Am I missing something? SQLiteDatabase db = mDbHelper.getReadableDatabase(); String select = "Select _id, title, title_raw from search Where(title_raw like " + "'%Smith%'" + ")"; Cursor cursor = db.query(TABLE_NAME, FROM, select, null, null, null, null); startManagingCursor(cursor); return cursor; 回答1: This will return you the required cursor Cursor cursor = db.query(TABLE_NAME, new String[] {"_id",

问题 Here is my query given below. select * from data where value = "yes"; My id is auto increment and below there is result of given query. id || value 1 || yes 3 || yes 4 || yes 6 || yes 9 || yes How to use ROW_NUMBER in sqlite? So that i can get result which is given below. NoId || value 1 || yes 2 || yes 3 || yes 4 || yes 5 || yes ROW_NUMBER AS NoId. 回答1: Try this query select id, value, (select count(*) from tbl b where a.id >= b.id) as cnt from tbl a FIDDLE | id | value | cnt | -------------

问题 I am creating a signup page, when I enter different passwords, toast is working just fine. But when I enter same passwords. MainActivity is not being redirected to a yaya Activity . It just crashes with a message "app stopped working" and I'm redirected to my main activity again. package com.example.abcd.helloworld; import.... public class SignUp extends Activity { DatabaseHelper helper = new DatabaseHelper(this); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate