How to open SQLite connection in WAL mode

问题

In C#, how to open an SQLite connection in WAL mode?

Here is how I open in normal mode:

SQLiteConnection connection = new SQLiteConnection("Data Source=" + file);
connection.Open();
// (Perform my query)

回答1:

how about a factory approach to specify in the SQLiteConnection connetion string ?

for e.g

public static class Connection
{
    public abstract SQLiteConnection NewConnection(String file);
}

public class NormalConnection : Connection 
{
  public override SQLiteConnection NewConnection(String file)
  {
     return new SQLiteConnection("Data Source=" + file);
  }
}

public class WALConnection : Connection 
{
  public override SQLiteConnection NewConnection(String file)
  {
    return new SQLiteConnection("Data Source=" + file + ";PRAGMA journal_mode=WAL;"
  }
}

The code is not tested, but I hope you can get the idea, so when you use it you can do like that.

   SQLiteConnection conWal = new WALConnection(file);
    conWAL.Open();

    SQLiteConnection conNormal = new NormalConnection(file);
    conNormal.Open();

回答2:

The line below is what I was looking for, many thanks to Turbot whose answer includes it:

new SQLiteConnection("Data Source=" + file + ";PRAGMA journal_mode=WAL;")

回答3:

Persistence of WAL mode

"Unlike the other journaling modes, PRAGMA journal_mode=WAL is persistent. If a process sets WAL mode, then closes and reopens the database, the database will come back in WAL mode."

http://www.sqlite.org/wal.html

If I understand it correctly, this means that you can set WAL mode for a database once, there's no need to set it on every connection.

You can do it with the command line shell for SQLite: http://www.sqlite.org/sqlite.html

回答4:

Here is my less-than-perfect solution:

SQLiteConnection connection = new SQLiteConnection("Data Source=" + file);
connection.Open();
using (var command = new SQLiteCommand(sqliteConnection))
{
    command.CommandText = "PRAGMA journal_mode=WAL";
    command.ExecuteNonQuery();
}
// (Perform my query)

If you know something less verbose, I would be happy to hear about it!

来源：https://stackoverflow.com/questions/15870104/how-to-open-sqlite-connection-in-wal-mode

标签

sqlite

wal