i'm using berkeley db and i'm new to it.
I have noticed that whenever i start the berkeley the file " __db.001" is created in my directory
and it consists of 1 line
May you please explain to me what is the use of that file?
Thanks, in advance
These files are used by Berkeley DB internally by the shared environment (DBEnv) to coordinate multi-process access to the database.
See also ___db.001
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 use phonegap for my application. i create sqlite database and copied it on memory card.
Is it possible to read data from the database on a memory card
thank you and sorry for my poor english.
No. You can't read the database from a custom path. The PhoneGap/Cordova expects the database to be in particular location. If not present, it will create a new database.
But you can move the content to the expected location and start working on it.
Some links to help are:
http://www.raymondcamden.com/2012/7/27/Guest-Blog-Post-Shipping-a-populated-SQLite-DB-with-PhoneGap
http://gauravstomar.blogspot.in/2011/08/prepopulate-sqlite-in-phonegap.html
we are using berkeleydb java edition db base api, we have already read/write CDRFile of 9 lack rows with transaction and without transaction implementing secondary database concept the issues we are getting are as follows:-
with transaction----------size of database environment 1.63gb which is due to no. of log files created each of 10 mb.
without transaction-------size of database environment 588mb and here only one log file is created which is of 10mb. so we want to know how this happens..
how log files are created and what is meant of using transaction and not using transaction in db environment and what are this db files _db.001,_db.002,_db.003,_db.004,__db.005 and log files like log.0000000001.....plz reply soon
It looks like this question was already answered here what are log files and why they are created during transaction in berkeleydb core api(dbapi)?.
From your description it actually looks like you're using Berkeley DB core, not Java Edition. __db.001 through __db.005 are the shared region system environment files. The environment files are described here. The log.* files are the transaction log files. The transaction log files are described in the answer referenced above.
These types of questions can often be more easily/quickly answered on the Berkeley DB forum on OTN.
Regards,
Dave
i am new to berkeley db . i have installed the berkely db using link text
so i need to create my first db i have checked the sample programs but i coudnt find it easy please help me to create an sample db ...and how to use the API for java
Your best bet is to read the documentation starting with the Getting Started Guide.
Your best bet is to read the documentation starting with the Getting Started Guide.
Is it possible somehow to create in-memory database in SQLite and then destroy it just by some query?
I need to do this for unit testing my db layer. So far I've only worked by creating normal SQLite db file and delete if after all tests, but doing it all in memory would be much better.
So is it possible to instanciate database only in memory without writing anything to disc?
I can't use just transactions, because I want to create whole new database.
Create it with the filename ":memory:": In-Memory Databases.
It'll cease to exist as soon as the connection to it is closed.
As an alternative to in memory databases, you can create a SQLite temporary database by using an empty string for the filename. It will be deleted when the connection is closed. The advantage over an in-memory database is your databases are not limited to available memory.
Alternatively, you can create your database in a temp file and let the operating system clean it up. This has the advantage of being accessible for inspection.
I'd suggest mounting a tmpfs filesystem somewhere (RAM only filesystem) and using that for your unit tests.
Instantiate DB files as normal then blow them away using rm - yet nothing has gone to disk.
(EDIT: Nice - somebody beat me to a correct answer ;) Leaving this here as another option regardless)
I suggest you using lmDisk toolkit.
It's a tool kit to mount a part of ram or image file as normal disk. you can copy your project (or just your db) there.
I've try it to process raw data and create a db for a game ai.