I am fairly new to programming java and I just started working with SQLite databases. A school assignment is requiring me to create a stand alone GUI program that can store data. After some research, I will be using a SQLite manager downloaded from Firefox. After completing my project, will it still able to run stand alone? Or will the SQLite manager be required to input data. Thank you
Yes, if you include the respective SQLite libraries. In fact there is little need for the SQLite Manager although the resultant file could be copied and used.
In short the SQLite database is a file that you open (connect to) using the respective library functions/API. Noting that some functionality may depend upon the version of SQLite (which could well be lower on the SQLite Manager).
You could also manage without the SQLite Manager, creating the database and tables therein within the program. Generally you'd use a SQLite Manager to provide a pre-populated database (noting that if using a pre-populated database that identifiers (table and column names) should match (case doesn't matter)).
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Ship an application with a database
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I am building a Quiz app to practice what I've learned so far. I want to retrieve data from the sql lite. Entering data in a non embedded RDMBS is trivial. With SQL lite I just don't know what to do. What steps you guys suggest? I am using Room database.
Room 2.2.0 and higher has built-in support for initializing your database from an existing database.
So, if you wanted to hand-populate your database, roughly speaking, the steps would be:
Set up your Room entities and RoomDatabase in your app
Run your app and have Room create an empty database for you
Copy that database off of your device or emulator (e.g., using Android Studio's Device File Explorer tool)
Use a SQLite client to add rows to your tables with the proper data
Put that database in assets/ within your project
Modify your RoomDatabase setup to use createFromAsset()
If it is more convenient for you to maintain your data in some other format (JSON, XML, CSV, whatever), you have two main choices:
Generate the Room database from that data on your development machine (e.g., via a custom Gradle task) and package the database, or
Package the raw data (e.g., JSON) in your app, parse that, and use that to populate your database
For example, in this sample app I wanted to demonstrate Room's full-text search (FTS) support. I wanted to use the contents of a book, and that was going to be easier to maintain as plain text files. So, I package the plain text files in the app and populate the Room database from there.
(I am hoping to have a createFromAsset() sample in the future)
My application does not use internet, though I am using php(json) to get certain data from a local mysql database and parse the JSONObject to Java and save it to sqlite in Android.
I am using this to dynamically populate my android menus from the mysql data(local database). I think this call for a better practice when it comes in getting updates in the database. I will be deleting the previous menu in my sqlite and fetch another data from mysql.
What I did since I want to update my sqlite database, I incremeted my database version if there are new updated. Also I put an indicator from my outside database so that my app can check if there are available updates.
I cannot understand how distributing Java programs that use a database works.
Let's say I am using Derby as RDBMS and I want to store tasks and calendar entries in a database.
I want each user of the program to have a local database.
But I don't understand how in-memory databases are supposed to work. Should I write a script so that the first time my program is launched it creates a database and empty tables? Or will they be already created during the installation of the program?
If your program wants to store the user's tasks and calendar entries in a database, you probably don't want to use an in-memory database, because the in-memory database disappears when your program exits.
Rather, you want to use an ordinary persistent Derby database, which will store the user's data in files in a folder on the filesystem.
You do indeed have to create the database and issue the CREATE TABLE etc. statements to create the tables in that database. You could provide that as a separate script, or you could have your program issue those statements itself.
Tables are not automatically created, though; you have to issue the CREATE TABLE statements one way or another.
So I'm following a tutorial on how to create a simple Android app that stores a bunch of random quotes. I've noticed that they used a SQLite database and many other Android tutorials uses SQLite to store things. I'm not very used to SQLite. Can I achieve the same result just by storing the quotes in a hashtable?
What are the differences between a SQLite database and a hashtable in terms of performance?
What are the differences between a SQLite database and a hashtable in terms of performance?
An (in-memory) hash table is (you probably should use HashMap) is going to be faster. However, it does not address the problem of making your quotes "persist" when your app has shut down.
SQLite is a database, and the main point of a database is that the data persists.
(There are a whole bunch of other benefits in using a database of some kind. One that is potentially relevant to you is that you can store more stuff in a typical database than you can hold in memory. The database stores stuff on your device's hard drive / SSD / whatever which has far more capacity than main memory.)
http://www.brighthub.com/mobile/google-android/articles/25023.aspx
I suggest SQLite because u can access the database very easily and it is easy to understand and view the database tables also very easy through DDMS plugin for eclipse The above link helps you in DDMS
It's up to your intention. If you want to store data such as app preference, user score.. use SQLite. These data will be available for the next launch of application. Hashtable is in memory, of course it is faster than SQLite, all information stored in Hashtable will be lost when the app is deactived or terminated.
I have this requirement for my business. We have a swing desktop application that works with a mysql database. At the end of each day the swing app exports the data that has changed and uploads it to a server. The set up is, a user working in an office, will have many companies that he is working with. If he changes any data for that company, then I export that company's data alone from the database. The data is exported in the form of java objects, serialised and stored into a file which gets uploaded.
The next day, if there are any changes made to that company again then I will replace the file in the server with the latest uploaded file.
Now on my server, I would like to work with this file. I would like to convert each of these files into mini databases that a webapp can read. It will not write to it. Everytime the user uploads, the database will be deleted and recreated.
So ultimately each of these files are a small subset of the data that a user has in his desktop application.
Now this issues are:
The objects that I have exported are "Apache Torque" objects. Torque is an ORM tool, basically the object represents the table. I need to convert this object into a database. Sqlite, HSQLDB, Derby...? The database should be small. If the object file is about 5KB, then the database that represents that file shouldnt be 3MB. Derby did that actually.
The java object classes could change. Since the underlying database could change. Hence I will need to deserialise these objects and create a database from it as soon as it is uploaded. Otherwise, I will not be able to deserialise these objects later on. Small changes to the database is fine for the web application. But if I dont deserialise it immediately, then I am stuck.
The conversion from the java object to the database should be fast. Since the user actually waits when his data is getting uploaded I would like to add a maximum of 5-10s additional for the conversion.
Is it ok to have thousands of these mini databases lying around? Is this design okay? Is there an alternate solution?
I wouldn't try to put each dataset into its own database. I would put all of them in one big database, along with a column in the key tables indicating the dataset that each row applies to (this sounds like it should just be a company identifier). This is a more normalised design than having many small databases.
You will then need to write the webapp so it makes queries for particular datasets, rather than connecting to a particular database.
if you adopt that approach, you can deserialize and store the datasets as soon as they arrive. The storage is simply inserting rows into an existing database, so it should be very fast.
In addition, i expect that one big database will be much easier to manage, maintain, report on, etc, than many small databases.
If you tell us more about the details of your schema, we could discuss how the database could be organised, if that would be useful.