Everything I have read so far, it seems as though you copy the DB from assets to a "working directory" before it is used. If I have an existing SQLite DB I put it in assets. Then I have to copy it before it is used.
Does anyone know why this is the case?
I can see a possible application to that, where one doesn't want to accidentally corrupt database during write. But in that case, one would have to move database back when it's done working on it, otherwise, next time program is run will start from "default" database state.
That might be another use case - you might always want to start program execution with known data state. Previous state might be set from external application.
Thanks everyone for your ideas.
I think what I might have figured out is that the install cannot put a DB directly to the /data directory.
In Eclipse there is no /data which is where most of the discussions I have read say to put it.
This is one of the several I found:
http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/comment-page-4/#comment-37008
Related
I have a Node-RED flow. It uses a sqlite node. I am using node-red-node-sqlite. My OS is Windows 10.
My sql database is configured just with name "db" :
My question is, where is located the sqlite database file?
I already search in the following places, but didn't found:
C:\Users\user\AppData\Roaming\npm\node_modules\node-red
C:\Users\user\.node-red
Thanks in advance.
Edit
I am also using pm2 with pm2-windows-service to start Node-RED.
If you don't specify a full path to the file in the Database field it will create the file in the current working directory for the process, which will be where you ran either node-red or npm start.
Use full path location with file name.
It should work i guess.
This isn't a valid answer, just a workaround for those who have the same problem.
I could't find my database file. But inside Node-RED everything worked just great. So. this is what I have done as a workaround:
In Node-RED, make some select nodes to get all data from tables
Store the tables values somewhere (in a .txt file or something like that)
Create your database outside Node-RED, somewhere like c:\sqlite\db.db. Check read/write permissions
Create the tables and insert the values stored from old database
In Node-RED, inside "Database", put the complete path of the database. For example, c:\sqlite\db.db
In my case this was easy because I only had two database with less than 10 rows.
Hope this can help others.
Anyway, still waiting for a valid answer :)
I'm working on a project that has some pretty specific requirements, and am running in to a problem with one of them. We have a locked SQLite database. We can't unlock this database, but need to read it (but not write to it), and we cannot create any new files on the filesystem that contain the data from this database. What was suggested is to read the file in to RAM, and then access it from there. I've been trying to find out a way to do this, but this project is on Windows, so it's not going as smoothly as it might otherwise.
What I've been trying to do is read the file in to a bash variable, and then pass that variable to sqlite as the database. This hasn't been working particularly well.
I installed win-bash, but when I do "sqlite3.exe <(cat <<<"$database")" I get a 'syntax error near unexpected token `<('" I checked, and win-bash looks like it's based on an older version of bash. I tried zsh, but it's saying "doesn't look like your system supports FIFOs.". I installed cygwin, which wouldn't really be a good solution anyway (once I figure out how to do this, I need to pass it off to our Qt developers so that they can roll it in to a Qt application) but I was just trying to do a 'proof of concept' - that didn't work either. Sqlite opened just fine, but when i ran ".tables", it said "Error: unable to open database "/dev/fd/63": unable to open database file" So, it looks like I'm barking up the wrong tree, and need to think of some other way to do this.
I guess my questions are, first, is it possible to read a sqlite database in a variable as I was attempting, or am I going down an entirely incorrect path there? Second - if it can't be done that way, is there some way I'm overlooking that might make this possible?
Thanks!
I'm working with a customer using the InterSystems cache' database environment and they are asking what's the best way to deal with the .pck file that's part of the database structure. When I attempted to research this to understand their ask, I came up short nearly every place on what this file is, where it's located, and how or why it's problematic.
any advice would be helpful
tom
Since we got that you talk about LCK file, it becomes more clear.
Well, lck file, is a kind of lock file, for databases in Caché. Which should be close to the mounted database (CACHE.DAT file) all the time when the system is running, preventing to use this database to write from another Caché instance. While Caché correctly shutdowns it is clear lck files created before.
While you touched backup theme for Caché Databases. I can say if lck files appeared to be backuped as well, something going wrong in a backup process. Depending on a way chosen to backup databases, you should not even have lock files existed during a backup process. Or you just should not backup it. While you mentioned freeze in comment, in this case lock files can still exist, and just have to copy only CACHE.DAT, it should be safe. But without freeze copy databases from working server quite dangerous, and nobody can guarantee that database will not have integrity errors.
I use BerkeleyDb in a project.
I have some environments composed by several file. Sometimes, I need to remove some of these files.
When I remove file with the filesystem, opening the environment raise an error No such file or directory.
Do exists a way to safely removing a file in BerkeleyDb environment ?
To remove a database, you need to be absolutely certain that no references to the database exist in the environment. The most foolproof way to do this is as follows:
Use db->remove() to remove the database from inside your application.
Use dbenv->txn_checkpoint() to flush all changes, checkpoint the log, and then flush the log.
Use dbenv->txn_checkpoint() with the DB_FORCE flag to push one more checkpoint through, ensuring that when the environment is recovered that it doesn't attempt to recover databases that predated the last checkpoint.
Step 3 sounds insane, I know. And maybe it isn't needed any more. But it certainly was needed in the not-too-distant past. Certainly steps 1 and 2 are needed. You'll need to experiment to see if step 3 is necessary for your application.
I am publishing an AIR app in debug mode using FlashDevelop and have included a database in the files/folders to be published.
When the app first launches it checks whether there is an instance of this db in the applicationStorageDirectory, if there isn't it copies the included one from the applicationDirectory to the applicationStorageDirectory.
This should mean that the referenced database dbFile = File.applicationStorageDirectory.resolvePath(DB_FILE_NAME); should now be writable, however when i run the app i can read the records from the table but when i attempt to write using an SQL statement I get an SQLError: 'Error #3122: Attempt to write a readonly database'.
I know that this would be thrown if i was attempting to write to the read only location of the applicationDirectory but i'm certainly using the File.applicationStorageDirectory location which should (as far as i know) be writable.
The location of the db on my Windows 7, 64bit = C:\Users\sean.duffy\AppData\Roaming\FishFightAppData\Local Store\db this is found using the dbFile.nativePath property so again i'm sure i should be able to update the db.
Anyone got any ideas? I have tried everything i could think of and searched all over but the only common cause seems to be when people try to write to the asplicationDirectory and not the storage directory....
UPDATE::
My bad - have just realised that i've misread the API of the 3rd party library i'm using! I should have been calling executeModify(statement) which can modify the contents of the db, instead i'm calling execute(statement) which doesn't/can't overwrite the db.
The source code is compiled into a swc and there was no documentation to point out you needed to use executeModify, although i should have guessed from the name i suppose!
Sorry about that and thanks for your help
(As a public courtesy to get this off the unanswered list, I am reposting the apparent solution. As usual, the asker is more than welcome to ignore mine and post it themselves and accept their own answer.)
In this API, you need to call executeModify(statement), not execute(statement). The latter does not overwrite the database.