24

I'm currently thinking of using SQLite as db engine for my C# project, but i ran into the following problem: i can't find any API for memory storage. What i want to achieve is the following:

Upon start of the program i want to load the db file (from HDD) into memory. During execution of the program i want to use this memory stream as a real db (read,write,insert,select etc). Upon closing save the stream to the file.

Can anyone point me in the right way or suggest another db engine that would be better suited for this purpose.

1 Answer 1

48

You can use SQLite Online Backup API that has ability to copy db file to memory, memory to file. Native support for SQLite Online Backup API is present in System.Data.SQLite from version 1.0.80.0 (with SQLite 3.7.11).

This is simple example how API can be used in C#:

SQLiteConnection source = new SQLiteConnection("Data Source=c:\\test.db");
source.Open();

using (SQLiteConnection destination = new SQLiteConnection(
  "Data Source=:memory:"))
{
  destination.Open();               

  // copy db file to memory
  source.BackupDatabase(destination, "main", "main",-1, null, 0);
  source.Close();

  // insert, select ,...        
  using (SQLiteCommand command = new SQLiteCommand())
  {
    command.CommandText =
      "INSERT INTO t1 (x) VALUES('some new value');";

    command.Connection = destination;
    command.ExecuteNonQuery();
  }             

  source = new SQLiteConnection("Data Source=c:\\test.db");
  source.Open();

  // save memory db to file
  destination.BackupDatabase(source, "main", "main",-1, null, 0);
  source.Close();               
}
Sign up to request clarification or add additional context in comments.

8 Comments

Thank you, for this nice and clean solution.
Is there a way to do the same thing to get the byte[] without touching disk?
Warning: Using the Backup API for an in-memory database removes Durability guarantees.
@Gleno: You take the byte[] and save to a temp file (temp.db), then use the backup API to to copy it into a memory db. Then make changes. Then store to temp.db again using backup api. Then read the temp.db back into byte[].
This API is written in C. how can i use this API with mono? please suggest
|

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.