Entity Framework Core–Change naming conventions for PostgreSQL

The default naming conventions for Entity Framework Core are quite annoying when using PostgreSQL. EF Core generates all databases objects using Pascal Casing, as a consequence you have to add quotes to all queries which exactly ain’t fun if you have to write some queries by hand.

Let’s update the naming convention to use snake_case which is what PostgreSQL expects.

Let’s start by adding a simple ToSnakeCase extension method:

	public static class StringExtensions
	{
	public static string ToSnakeCase(this string input)
	{
	var startUnderscores = Regex.Match(input, @"^_+");
	return startUnderscores + Regex.Replace(input, @"([a-z0-9])([A-Z])", "$1_$2").ToLower();
	}
	}

view raw StringExtensions.cs hosted with ❤ by GitHub

Now it’s time to update our OnModelCreating method and change the naming convention:

	public class SampleDbContext : DbContext
	{
	public SampleDbContext(DbContextOptions options)
	: base(options)
	{ }
	protected override void OnModelCreating(ModelBuilder builder)
	{
	base.OnModelCreating(builder);
	foreach(var entity in builder.Model.GetEntityTypes())
	{
	// Replace table names
	entity.Relational().TableName = entity.Relational().TableName.ToSnakeCase();
	// Replace column names
	foreach(var property in entity.GetProperties())
	{
	property.Relational().ColumnName = property.Relational().ColumnName.ToSnakeCase();
	}
	foreach(var key in entity.GetKeys())
	{
	key.Relational().Name = key.Relational().Name.ToSnakeCase();
	}
	foreach(var key in entity.GetForeignKeys())
	{
	key.Relational().Name = key.Relational().Name.ToSnakeCase();
	}
	foreach(var index in entity.GetIndexes())
	{
	index.Relational().Name = index.Relational().Name.ToSnakeCase();
	}
	}
	}
	}

view raw SampleDbContext.cs hosted with ❤ by GitHub

That’s it!