If you’re running a .NET application that doesn’t require a database, one of the options that you can use is having In Memory Database. What this means is that you are using the machine’s RAM to store data for your application.

There are multiple ways of implementing these:

  • Plain C# object / list / dictionary / hash table
  • Dependency Injection with proper lifetime (singleton/trancient/scoped)
  • Using SQLite (preferred)

Why use it?

  • If you need a temporary place to store your data. This is often used when the machine is offline.
  • An efficient (cheap and fast) way of retrieving small data within a short lifecycle such as configurations and logs.
  • The machine is capable enough to handle the storage size. As of right now, RAM is relatively cheap compared to latency (network) costs.

When not to use it?

  • If you need to store the data for future use. When the machine restarts, or when the application closes, all of your data will be flushed.
  • If you need to centrally store it so that other applications can consume it.
  • This is not meant to store large number of data set.

Sample Application in SQLite

One of the advantages of using SQLite is the ability to treat the data store just like a SQL database. You can perform simple T-SQL query statements and even use Entity Framework.

using Microsoft.Data.Sqlite;

const string connectionString = "Data Source=InMemorySample;Mode=Memory;Cache=Shared";

var masterConnection = new SqliteConnection(connectionString);

var createCommand = masterConnection.CreateCommand();
createCommand.CommandText =
                CREATE TABLE data (
                    value TEXT

using (var firstConnection = new SqliteConnection(connectionString))

    var updateCommand = firstConnection.CreateCommand();
    updateCommand.CommandText =
                    INSERT INTO data
                    VALUES ('Hello, memory!')

using (var secondConnection = new SqliteConnection(connectionString))
    var queryCommand = secondConnection.CreateCommand();
    queryCommand.CommandText =
                    SELECT *
                    FROM data
    var value = (string)queryCommand.ExecuteScalar();


The most important bits:

  • Reference the Microsoft.Data.Sqlite nuget package.
  • In the connection string, add the following Mode=Memory;Cache=Shared