EventStore.sql

USE EventStore;
GO

CREATE TABLE dbo.Events
(
    [Id] UNIQUEIDENTIFIER NOT NULL PRIMARY KEY,
    [Type] NVARCHAR(256) NOT NULL,
    [Data] NVARCHAR(MAX) NOT NULL,
    [Version] INT NOT NULL,
    [StreamName] NVARCHAR(256) NOT NULL,
    [Timestamp] DATETIMEOFFSET(7) NOT NULL DEFAULT SYSDATETIMEOFFSET(),
    UNIQUE ([StreamName], [Version]),
    CHECK ([Version] > 0)
);
GO

CREATE NONCLUSTERED INDEX IX_Events_StreamName ON [Events] ([StreamName]);
GO

CREATE TYPE NewEvent AS TABLE
(
    [Id] UNIQUEIDENTIFIER NOT NULL,
    [Type] [NVARCHAR](256) NOT NULL,
    [Data] [NVARCHAR](MAX) NOT NULL
);
GO

CREATE TABLE [Snapshots]
(
    [Id] UNIQUEIDENTIFIER NOT NULL PRIMARY KEY,
    [Description] [NVARCHAR](1024) NOT NULL,
    [Data] [NVARCHAR](MAX) NOT NULL,
    [Version] [INT] NOT NULL,
    [Timestamp] [DATETIMEOFFSET](7) NOT NULL DEFAULT SYSDATETIMEOFFSET(),
    [StreamName] NVARCHAR(256) NOT NULL,
    UNIQUE ([StreamName], [Version]),
    CHECK ([Version] > 0)
);
GO

CREATE PROCEDURE dbo.GetStreams
    @StreamName NVARCHAR(256) = NULL,
    @Page INT = 1,
    @PageSize INT = 25
AS

SELECT
    [StreamName],
    MAX([Version]) AS [Version],
    MAX([Timestamp]) AS [Timestamp]
FROM [dbo].[Events]
WHERE (@StreamName IS NULL OR [StreamName] = @StreamName)
GROUP BY [StreamName]
ORDER BY [StreamName]
OFFSET (@Page - 1) * @PageSize ROWS
FETCH NEXT @PageSize ROWS ONLY
OPTION
(RECOMPILE);

SELECT COUNT(DISTINCT [StreamName]) AS [TotalCount]
FROM [dbo].[Events]
WHERE (@StreamName IS NULL OR [StreamName] = @StreamName)
OPTION
(RECOMPILE);
GO

CREATE PROCEDURE [dbo].[GetStream]
    @StreamName NVARCHAR(256)
AS
BEGIN
    SELECT
        [StreamName],
        MAX([Version]) AS [Version],
        MAX([Timestamp]) AS [Timestamp]
    FROM [dbo].[Events]
    WHERE [StreamName] = @StreamName
    GROUP BY [StreamName];
END
GO

CREATE PROCEDURE [dbo].[GetEvents]
    @StreamName NVARCHAR(256),
    @StartAtVersion [INT] = 0
AS
BEGIN
    SELECT
        [Id],
        [StreamName],
        [Type],
        [Data],
        [Version],
        [Timestamp]
    FROM [dbo].[Events]
    WHERE [StreamName] = @StreamName
        AND [Version] >= @StartAtVersion
    ORDER BY [Version];
END
GO

CREATE PROCEDURE dbo.SaveEvents
    @StreamName NVARCHAR(256),
    @StreamVersion INT,
    @NewEvents NewEvent READONLY
AS

BEGIN
    BEGIN TRANSACTION

    DECLARE @ExpectedVersion INT;

    BEGIN TRY
        SELECT @ExpectedVersion = COALESCE(MAX([Version]), 0)
    FROM [dbo].[Events]
    WHERE [StreamName] = @StreamName;
    
    IF @ExpectedVersion <> @StreamVersion
        BEGIN
            DECLARE @ErrorMessage NVARCHAR(256) = CONCAT('Concurrency violation: expected stream version to be ', CAST(@ExpectedVersion AS VARCHAR(256)));
            
            ;THROW 50001, @ErrorMessage, 1;
        END
        
    INSERT INTO [dbo].[Events]
        (
        [Id],
        [StreamName],
        [Type],
        [Data],
        [Version]
        )
    SELECT
        [Id],
        @StreamName,
        [Type],
        [Data],
        (row_number() over (order by (select NULL)) + @ExpectedVersion)
    FROM @NewEvents;    

        COMMIT TRANSACTION
    END TRY
    BEGIN CATCH
        IF @@TRANCOUNT > 0
        BEGIN
        ROLLBACK TRANSACTION;
    END;

        THROW;
    END CATCH
END
GO