diff --git a/src/Strata.SqlTools.LinqToSql/Breakdowns/LinqQueryBreakdown.cs b/src/Strata.SqlTools.LinqToSql/Breakdowns/LinqQueryBreakdown.cs
index 341b1fa..db49c0a 100644
--- a/src/Strata.SqlTools.LinqToSql/Breakdowns/LinqQueryBreakdown.cs
+++ b/src/Strata.SqlTools.LinqToSql/Breakdowns/LinqQueryBreakdown.cs
@@ -185,39 +185,31 @@ public class LinqQueryBreakdown : QueryBreakdown
/// Gets a LINQ to SQL query of the specified type based on this breakdown.
///
/// The entity type for the query.
- /// An IQueryable of the specified type reconstructed from the breakdown, or null if the type doesn't match the original entity type.
+ /// An IQueryable of the specified type reconstructed from the breakdown; an empty queryable if the type doesn't match the original entity type or the original data source isn't available.
///
/// This method attempts to reconstruct a LINQ query from the analyzed components (WHERE, ORDER BY, etc.).
/// If a data source (IQueryable) is available in the breakdown's OriginalExpression, it will be used.
- /// Otherwise, returns null to indicate the query cannot be reconstructed without the original data source.
+ /// Otherwise, returns an empty queryable — breakdown analysis is one-way; reconstruction requires the original provider.
///
- public override IQueryable? GetQuery() where T : class
+ public override IQueryable GetQuery() where T : class
{
- // If we don't have the original expression, we cannot reconstruct the LINQ query
if (OriginalExpression == null)
{
- return null;
+ return Enumerable.Empty().AsQueryable();
}
- // The original expression is the full LINQ query that was analyzed
- // To use it, we need it to be an IQueryable
try
{
- // If the original expression can be converted to IQueryable, use it
- // Otherwise, we cannot safely reconstruct without the original query provider
if (OriginalExpression is Expression && EntityType == typeof(T))
{
- // We have the expression, but we don't have the provider to create IQueryable
- // The breakdown analysis is one-way; reconstruction requires the original provider
- return null;
+ return Enumerable.Empty().AsQueryable();
}
- return null;
+ return Enumerable.Empty().AsQueryable();
}
catch
{
- // If any error occurs during reconstruction, return null
- return null;
+ return Enumerable.Empty().AsQueryable();
}
}
diff --git a/src/Strata.SqlTools.PostgreSql/Breakdowns/QueryBreakdown.cs b/src/Strata.SqlTools.PostgreSql/Breakdowns/QueryBreakdown.cs
index 30d2f74..0a07d1c 100644
--- a/src/Strata.SqlTools.PostgreSql/Breakdowns/QueryBreakdown.cs
+++ b/src/Strata.SqlTools.PostgreSql/Breakdowns/QueryBreakdown.cs
@@ -272,17 +272,13 @@ public class QueryBreakdown : SqlServerQueryBreakdown
/// Gets a LINQ to SQL query of the specified type based on this breakdown.
///
/// The entity type for the query.
- /// null by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.
+ /// An empty queryable by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.
///
- /// This PostgreSQL-specific implementation returns null since PostgreSQL QueryBreakdown represents parsed SQL statements.
+ /// This PostgreSQL-specific implementation returns an empty queryable since PostgreSQL QueryBreakdown
+ /// represents parsed SQL statements and has no built-in way to create LINQ queries.
/// Derived classes can override this method to reconstruct LINQ queries from the analyzed components.
///
- public override IQueryable? GetQuery() where T : class
- {
- // PostgreSQL breakdown represents parsed SQL statements and does not have a built-in way to create LINQ queries
- // Override in derived classes to provide LINQ query reconstruction if needed
- return null;
- }
+ public override IQueryable GetQuery() where T : class => Enumerable.Empty().AsQueryable();
}
diff --git a/src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdown.cs b/src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdown.cs
index 4ab2451..773f3f7 100644
--- a/src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdown.cs
+++ b/src/Strata.SqlTools.Snowflake/Breakdowns/QueryBreakdown.cs
@@ -863,17 +863,13 @@ public class QueryBreakdown : SqlServerQueryBreakdown
/// Gets a LINQ to SQL query of the specified type based on this breakdown.
///
/// The entity type for the query.
- /// null by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.
+ /// An empty queryable by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.
///
- /// This Snowflake-specific implementation returns null since Snowflake QueryBreakdown represents parsed SQL statements.
+ /// This Snowflake-specific implementation returns an empty queryable since Snowflake QueryBreakdown
+ /// represents parsed SQL statements and has no built-in way to create LINQ queries.
/// Derived classes can override this method to reconstruct LINQ queries from the analyzed components.
///
- public override IQueryable? GetQuery() where T : class
- {
- // Snowflake breakdown represents parsed SQL statements and does not have a built-in way to create LINQ queries
- // Override in derived classes to provide LINQ query reconstruction if needed
- return null;
- }
+ public override IQueryable GetQuery() where T : class => Enumerable.Empty().AsQueryable();
}
diff --git a/src/Strata.SqlTools.SqlBreakdown/Classes/SqlBreakdownBase.cs b/src/Strata.SqlTools.SqlBreakdown/Classes/SqlBreakdownBase.cs
index fa3d00a..4663657 100644
--- a/src/Strata.SqlTools.SqlBreakdown/Classes/SqlBreakdownBase.cs
+++ b/src/Strata.SqlTools.SqlBreakdown/Classes/SqlBreakdownBase.cs
@@ -57,13 +57,13 @@ public abstract class SqlBreakdownBase : ISqlBreakdown
/// Gets a LINQ to SQL query of the specified type based on this breakdown.
///
/// The entity type for the query.
- /// An IQueryable of the specified type, or null if the breakdown cannot be converted to a LINQ query.
+ /// An IQueryable of the specified type; an empty queryable if the breakdown cannot be converted to a LINQ query.
///
/// This method allows derived breakdown classes to reconstruct or generate LINQ queries
/// from the analyzed components (SELECT, WHERE, ORDER BY, etc.).
- /// The default implementation returns null.
+ /// The default implementation returns an empty queryable.
///
- public virtual IQueryable? GetQuery() where T : class => null;
+ public virtual IQueryable GetQuery() where T : class => Enumerable.Empty().AsQueryable();
///
/// Gets the complete SQL query including optional setup and finish clauses.
diff --git a/src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdown.cs b/src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdown.cs
index 5fe8692..d99f887 100644
--- a/src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdown.cs
+++ b/src/Strata.SqlTools.SqlServer/Breakdowns/QueryBreakdown.cs
@@ -731,18 +731,14 @@ public class QueryBreakdown : SqlBreakdownBase, IQueryBreakdown
/// Gets a LINQ to SQL query of the specified type based on this breakdown.
///
/// The entity type for the query.
- /// null by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.
+ /// An empty queryable by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.
///
- /// This base implementation returns null since QueryBreakdown represents parsed SQL statements.
+ /// This base implementation returns an empty queryable since QueryBreakdown represents parsed SQL statements
+ /// and has no built-in way to create LINQ queries.
/// Derived classes (such as LinqQueryBreakdown) can override this method to reconstruct LINQ queries
/// from the analyzed components.
///
- public override IQueryable? GetQuery() where T : class
- {
- // Base implementation returns null - SQL-based breakdowns don't have a built-in way to create LINQ queries
- // Override in derived classes (e.g., LinqQueryBreakdown) to provide LINQ query reconstruction
- return null;
- }
+ public override IQueryable GetQuery() where T : class => Enumerable.Empty().AsQueryable();
///
/// Gets the complete SQL query string (interface implementation).
diff --git a/tests/Strata.SqlTools.LinqToSql.Tests/LinqQueryBreakdownTests.cs b/tests/Strata.SqlTools.LinqToSql.Tests/LinqQueryBreakdownTests.cs
index 2a7f9b3..04c579d 100644
--- a/tests/Strata.SqlTools.LinqToSql.Tests/LinqQueryBreakdownTests.cs
+++ b/tests/Strata.SqlTools.LinqToSql.Tests/LinqQueryBreakdownTests.cs
@@ -513,21 +513,21 @@ public class GetQueryTests
}
[Test]
- public void GetQuery_LinqBreakdown_ReturnsNullByDefault()
+ public void GetQuery_LinqBreakdown_ReturnsEmptyByDefault()
{
// Arrange
var query = TestDataContext.Users.Where(u => u.Age > 18);
var breakdown = LinqQueryBreakdown.Analyze(query);
- // Act - GetQuery returns null because LinqQueryBreakdown needs the original provider
+ // Act - GetQuery returns empty because LinqQueryBreakdown needs the original provider
var result = breakdown.GetQuery();
// Assert
- Assert.That(result, Is.Null);
+ Assert.That(result, Is.Empty);
}
[Test]
- public void GetQuery_SqlServerQueryBreakdown_ReturnsNull()
+ public void GetQuery_SqlServerQueryBreakdown_ReturnsEmpty()
{
// Arrange
var breakdown = new QueryBreakdown("Id, Name", "Users", "Age > 18");
@@ -536,11 +536,11 @@ public class GetQueryTests
var result = breakdown.GetQuery();
// Assert
- Assert.That(result, Is.Null);
+ Assert.That(result, Is.Empty);
}
[Test]
- public void GetQuery_MultipleBreakdownTypes_AllReturnNull()
+ public void GetQuery_MultipleBreakdownTypes_AllReturnEmpty()
{
// Arrange
var linqBreakdown = LinqQueryBreakdown.Analyze(TestDataContext.Users);
@@ -553,8 +553,8 @@ public class GetQueryTests
Assert.Multiple(() =>
{
// Assert
- Assert.That(linqResult, Is.Null);
- Assert.That(sqlResult, Is.Null);
+ Assert.That(linqResult, Is.Empty);
+ Assert.That(sqlResult, Is.Empty);
});
}