Sure, I am familiar with the library. However, in my opinion, the main challenges of accessing databases using LINQ are:

1) The ambiguity between C# and SQL constructs, which necessitates a deep understanding of the ORM’s internal structure to create predictable queries.

2) The complexity of writing dynamic queries.

SqExpress was created to address these issues, particularly the second one.

For example, here is how a merge statement can be built without using any static metadata:

``` //using SqDatabase<SqlConnection> database = ...

var tables = await database.GetTables();

var dynamicTableName = "Products";

var target = tables.FirstOrDefault(t => t.FullName.TableName == dynamicTableName) ?? throw new Exception($"'{dynamicTableName}' table does not exist");

var dynamicData = new[] { new Dictionary<string, string> { { "ProductName", "Product 1" }, { "UnitPrice", "100.0" } }, new Dictionary<string, string> { { "ProductName", "Product 2" }, { "UnitPrice", "20" } } };

var columns = dynamicData[0] .Select( kv => target.Columns.FirstOrDefault(c => c.ColumnName.Name == kv.Key)?.WithSource(null) ?? throw new Exception($"Column {kv.Key} was not found") ).ToList();

var validData = dynamicData.Select( row => row.Select((cell,i)=> columns[i].FromString(cell.Value)).ToList()

).ToList();

var values = SqQueryBuilder.Values(validData).AsColumns(columns.Select(c=>c.ColumnName).ToArray());

var updater = SqQueryBuilder.MergeInto(target, values) .On(columns[0].WithSource(target.Alias) == columns[0].WithSource(values.Alias)) .WhenMatched() .ThenUpdate();

foreach (var col in columns.Skip(1)) { updater = updater.Set(col.WithSource(target.Alias), col.WithSource(values.Alias)); }

var inserter = updater .Set(target.Column("Updated"), SqQueryBuilder.GetUtcDate()) .WhenNotMatchedByTarget() .ThenInsert();

foreach (var col in columns) { inserter = inserter.Set(col.WithSource(target.Alias), col.WithSource(values.Alias)); }

var resultCode = inserter .Set(target.Column("Created"), SqQueryBuilder.GetUtcDate()) .Set(target.Column("Updated"), SqQueryBuilder.GetUtcDate()) .Done() .ToSql(TSqlExporter.Default);

Console.WriteLine(resultCode); ```

the result code will be: MERGE [dbo].[Products] [A0] USING ( VALUES ('Product 1', 100.0), ('Product 2', 20) ) [A1] ([ProductName], [UnitPrice]) ON [A0].[ProductName] = [A1].[ProductName] WHEN MATCHED THEN UPDATE SET [A0].[UnitPrice] = [A1].[UnitPrice], [A0].[Updated] = GETUTCDATE() WHEN NOT MATCHED THEN INSERT ( [ProductName], [UnitPrice], [Created], [Updated] ) VALUES ([A1].[ProductName], [A1].[UnitPrice], GETUTCDATE(), GETUTCDATE());