How can i Access a SQLite DB which exists outside the application/database dir?
Looks like openOrCreate alway point to the appdir/database
You can only use getDatabasePath to get the path for the DB and assuming it is not null copy the file into the given location. The reasoning is that database might not be SQLite so it won't necessarily consist of one file. There is also the issue of filesystem which isn't very portable between platforms.
Related
net project as well as a setup project. I also have it so that during installation it asks the users to enter a file location to store their database. the plan is to have an empty .mdf file, with all the tables setup, copied into that folder and I store the folder path in a config file.
this is mainly because I am planning on having multiple separate applications that all need the ability to access the same database. I have it storing the folder path in my config file the only thing I'm having trouble with is
storing the template files I don't know if i should do this in the setup project or main project
how to copy said template files into a new folder
so far I have been unable to find a solution so any help is appreciated
Well here is what I do this in a few of my projects - something that has proven reliable enough for me over the years (which you may or may want to do as well):
I have the program itself create the database files in an initialization routine. First however, it creates the sub folders in which the database files will be stored, if they don't already exist.
To do this, the program just checks if the folder exists and if the database file exists and if they do not, it creates them on the spot:
If Directory.Exists(gSQLDatabasePathName) Then
Else
Directory.CreateDirectory(gSQLDatabasePathName)
End If
If File.Exists(gSQLiteFullDatabaseName) Then
Else
...
I also have the program do some other stuff in the initialization routine, like creating an encryption key to be used when storing / retrieving the data - but that may be more than you need (also, for full disclosure, this has some rare issues that I haven't been able to pin down).
Here too are some addition considerations:
I appreciate you have said that you want to give the user the choice of where to store their database files. However, I would suggest storing them in the standard locations
Where is the correct place to store my application specific data?
and only allowing the users to move them if the really need to (for example if the database needs to be shared over the network) as it will make the support of your app harder if every user has their data stored in different places.
I have found letting the user see in their options/settings windows where their database is stored is a good idea.
Also to encourage them to back those files /directories up.
Also to create automatic backups of several generations for the user.
Hope this helps.
Our current system database system is a clipper DOS application. The database inside its folder is fragmented/divided into many parts. I want to decrypt the database so that I will have only one database in all and avoid reshuffling of data. I'll attached the file folder Screenshot.. the database is on .DBF format
VScreenshot of files
Often you can decompile the CLIPPER exe file to source code and work from the .prg I've done it many times. The program to use is called WALKYRIE.
In Clipper and Fox Pro for DOS .dbf file is a simple table file.
If You want to use as data base with many tables in one unit.
You can import these tables in MS SQL data base and/or part of a MS Access database.
I see that you got several answers. Most are partially right. Let's address these one at a time:
All those files essentially comprise the "database" for the application you're using. They could be used by other applications as well. Besides having a lot of files, what is the problem you're trying to solve?
People mentioned indexes. You can generally ignore these. There are there primarily to make access to the data files faster. Any properly written clipper application will recreate these if they're missing or corrupted. You could test this by renaming one, running the app, and seeing what happens. If it doesn't recreate it you can name it back. Not replacing missing index files would be unusual behavior.
The DBF file format is binary, but barely. Most of what's in a DBF is text and is readable with an editor. But there's no reason to do so - I'm sure there are several free DBF utilities out there to to read DBF files. Getting the structure of the files could be very helpful.
Getting the data out of the files would also be fairly simple with a utility. If you look up the DBF format you could even write one fairly easily in Clipper, any other language that uses DBF files, or in something like Python. Any language that can open and write files, really. It's not hard - any competent developer could do this in a matter of hours. Must less if you're using Clipper or another language that natively reads DBX files.
Most people create dBase/Clipper programs with relational data, like SQL Server. Where SQL Server has tables that relate to each other dBase/Clipper has a file for each "table." This isn't a requirement, but it was almost certainly done this way.
Given that, if you get the table structures through a utility or by reading the headers in an editor (don't save them from an editor!) you could quite likely recreate the database schema (i.e. the map of the data). Once you have that it's fairly trivial to get the data into another type of database (SQL Sever, Access, or whatever you like to use.) If non of the files are too large it's conceivable to put all the files into Excel sheets. It really depends on what you want to do with it.
As others have said, you may be able to get the code by Valkyrie. Some people have used it very successfully. I don't know where you get it and I've never used it. Why do you not have the code? If this is a commercial application you likely should not have it. If it's a custom app who ever wrote it or paid to have it written should have the code.
Again, it's not clear to me what problem you're trying to solve. But there are many options for doing something with those DBF files. Fortunately they are one of the easier to read data formats you could be working with.
Let me know if you have any questions. Apologies for the typos that are no doubt scattered throughout this reply.
You sort of can get an idea of how they relate to each other by opening the index files they use (.NTX files). If you have the DBU utility (executable) around, you can open the DBF and load the index (NTX). LibreOffice Calc is also able to open DBFs (haven't tested .NTX).
If you open the .NTX on a text editor you will see the indexes in the beginning.
I open with Access, but I can save the data using a PrintFill Program.
Can any please explain that how we can embed ms access db in our winform application so that it could easily run on other machines with just one file .EXE . i have serached a lot but still unable to find an appropriate solution for it.Thanks in advance.
Assuming you are using an MDB, then the (32 bit) database engine (JET) is part of Windows. As such, there should be no setup requirements for that. If the database is only read and not written to, then you can add it as a resource to the EXE, and when the application starts up, extract the resource into either the TEMP directory, or if it's large and you don't mind leaving caches about, into a subfolder under local application data (CSIDL_LOCAL_APPDATA). If you do the latter, then the next time the application starts it can check to see whether a valid extracted MDB already exists and use that if it does. You can do a similar thing if the database is to be written to, but only for local storage, in which case the linked-in MDB would serve as a 'template' database.
If you were using Delphi or C++ I'd also suggest investigating SQLite as a possible alternative to JET, though as it's C# I assume (the 'c' tag is a bit confusing) then you won't be able to statically link the SQLite code, which fails the standalone EXE requirement.
I have a program which make use of a local database (sqlite3 and i use db module). What i want to do is using the database without knowing where it is.
For example, if i code the location of database in my program (like C:/my documents/my program/localdb.db), it is working correctly.
But if i just write "localdb.db", it doesn't find the database even if database is in the same folder with the .rkt file which use the database. (i dont know how but in earlier versions of my program, it was working).
Thus, how can i ensure to use the database without coding its location?
Thanks a lot!
Instead of "localdb.db", try using a runtime-path like this:
(define-runtime-path localdb "localdb.db")
and use localdb in place of the path string. You'll need to (require racket/runtime-path).
Currently in our research group, we have many "data files" stored on three servers and a couple of personal computers running different operating systems.
We want to build a database, which would store some information in addition to the URLs of those various "data files". My question is, do we have to copy all the data files and put them in a directory in the same server the database is in? Or can they be left as they are on the different computers? If the second case is ok, what would be the format of the url of the "data files"?
It really depends on what your intended goal is and what your current setup is like
If the files are currently sitting somewhere on the network, and you need a path that the application can use to access them, you just need to store the network path (\\server\share\file for Windows environments) in the database, then read it and access that path to access the files. You'll need to make sure everyone has read access to them.
If the files are currently accessible through a website URL, internal or external, then again, you just need to store that URL (or some portion thereof) (http://mywebsite.com/myfile or http://servername/myfile) and access that.
If either of the above are not currently true, but you want them to be, then you'll need to set up a new share/webserver and put the files there. There's no requirement that this be the same server as the database, but it'd make for better backups if it was.
If you want the files themselves to be in the database, you should check out Bob Fanger's link.
Not sure what you're asking here but...
If you want your database engine to read files filled with data, it probably doesn't matter where they are stored - though this may depend on the database you are using. Are you using MySQL? MS-SQL Server? Oracle?
Many database vendors provide relatively easy-to-use admin tools that would let you choose a file to be loaded, and usually the file chooser dialoge lets you browse networks so you could load a file over the network. Details on how to do this vary so consult the manual for your database engine for loading data from a pre-existing file.
Be aware that if the database is on Computer A and the data is being loaded from Computer B over the network, it will probably be slower than if the data was on the same computer as the database.
It doesn't really matter if the files are stored outside the database anyway.
See Storing Images in DB - Yea or Nay? for more thoughts on that one.
If the files accessible by an url, you can store that with the meta data, like
http://server1/folder/file.ext, file://\server1\folder\file.ext or "file://P:\folder\file.ext"
Things to consider:
Backups
Performance
Synchronisation between the meta-data and the data