Merge pull request 'chore(sonar)!: production-code cleanup — S1168 GetQuery + CA1822 static methods' (#15) from fix/sonarqube-prod-s1168-ca1822 into main

Reviewed-on: #15

src/Strata.SqlTools.LinqToSql/Breakdowns/LinqQueryBreakdown.cs

@@ -1,5 +1,5 @@
-using System.Linq.Expressions;
 using Strata.SqlTools.Breakdowns.SqlServer;
+using System.Linq.Expressions;
 using PostgreSqlBreakdown = Strata.SqlTools.Breakdowns.PostgreSql.QueryBreakdown;
 using SnowflakeBreakdown = Strata.SqlTools.Breakdowns.Snowflake.QueryBreakdown;
 
@@ -185,42 +185,42 @@ public class LinqQueryBreakdown : QueryBreakdown
     /// Gets a LINQ to SQL query of the specified type based on this breakdown.
     /// </summary>
     /// <typeparam name="T">The entity type for the query.</typeparam>
-    /// <returns>An IQueryable of the specified type reconstructed from the breakdown, or null if the type doesn't match the original entity type.</returns>
+    /// <returns>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.</returns>
     /// <remarks>
     /// 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.
     /// </remarks>
-    public override IQueryable<T>? GetQuery<T>() where T : class
+    public override IQueryable<T> GetQuery<T>() where T : class
     {
-        // If we don't have the original expression, we cannot reconstruct the LINQ query
         if (OriginalExpression == null)
         {
-            return null;
+            return GetEmptyQueryable<T>();
         }
 
-        // The original expression is the full LINQ query that was analyzed
-        // To use it, we need it to be an IQueryable<T>
         try
         {
-            // If the original expression can be converted to IQueryable<T>, 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<T>
-                // The breakdown analysis is one-way; reconstruction requires the original provider
-                return null;
+                return GetEmptyQueryable<T>();
             }
 
-            return null;
+            return GetEmptyQueryable<T>();
         }
         catch
         {
-            // If any error occurs during reconstruction, return null
-            return null;
+            return GetEmptyQueryable<T>();
         }
     }
 
+    /// <summary>
+    /// Get and empty queryable of T
+    /// </summary>
+    /// <typeparam name="T">The entity type for the query.</typeparam>
+    /// <returns>An empty IQueryable of the type.</returns>
+    public static IQueryable<T> GetEmptyQueryable<T>() where T : class
+        => Enumerable.Empty<T>().AsQueryable();
+
     /// <summary>
     /// Analyzes an INSERT operation for the given entity.
     /// </summary>

src/Strata.SqlTools.LinqToSql/Visitors/LinqExpressionVisitor.cs

@@ -277,7 +277,7 @@ public class LinqExpressionVisitor : ExpressionVisitor
         return base.VisitMember(node);
     }
 
-    private string ExtractSelectExpression(Expression expression)
+    private static string ExtractSelectExpression(Expression expression)
     {
         if (expression is NewExpression newExpr)
         {
@@ -303,7 +303,7 @@ public class LinqExpressionVisitor : ExpressionVisitor
         return string.IsNullOrEmpty(name) ? "*" : name;
     }
 
-    private string ExtractMemberName(Expression expression)
+    private static string ExtractMemberName(Expression expression)
     {
         if (expression is MemberExpression member)
         {

src/Strata.SqlTools.Markdown/Expressions/ExpressionGenerator.cs

@@ -245,7 +245,7 @@ public class ExpressionGenerator : IVisitor<string>
     /// <summary>
     /// Generates a Mermaid tree diagram from an Expression tree.
     /// </summary>
-    private string GenerateMermaidDiagram(Expression expression)
+    private static string GenerateMermaidDiagram(Expression expression)
     {
         var sb = new StringBuilder();
         sb.AppendLine("```mermaid");

src/Strata.SqlTools.Markdown/LinqToSql/QueryBreakdownGenerator.cs

@@ -8,27 +8,17 @@ namespace Strata.SqlTools.Markdown.LinqToSql;
 /// </summary>
 public class QueryBreakdownGenerator
 {
-    private readonly SqlServer.QueryBreakdownGenerator _baseGenerator;
-
-    /// <summary>
-    /// Initializes a new instance of the QueryBreakdownGenerator class.
-    /// </summary>
-    public QueryBreakdownGenerator()
-    {
-        _baseGenerator = new SqlServer.QueryBreakdownGenerator();
-    }
-
     /// <summary>
     /// Generates a Mermaid flowchart diagram from a LINQ to SQL QueryBreakdown.
     /// </summary>
     /// <param name="queryBreakdown">The LINQ QueryBreakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown diagram.</returns>
-    public string GenerateMermaidDiagram(LinqQueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateMermaidDiagram(LinqQueryBreakdown queryBreakdown, string? title = null)
     {
         // Since LinqQueryBreakdown inherits from SqlServer.QueryBreakdown,
         // we can use the base generator which works with the shared properties
-        return _baseGenerator.GenerateMermaidDiagram(queryBreakdown, title);
+        return SqlServer.QueryBreakdownGenerator.GenerateMermaidDiagram(queryBreakdown, title);
     }
 
     /// <summary>
@@ -85,7 +75,7 @@ public class QueryBreakdownGenerator
     /// <param name="queryBreakdown">The LINQ QueryBreakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing both diagrams.</returns>
-    public string GenerateCombinedDiagram(LinqQueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateCombinedDiagram(LinqQueryBreakdown queryBreakdown, string? title = null)
     {
         var sb = new System.Text.StringBuilder();
 

src/Strata.SqlTools.Markdown/LinqToSql/SqlStatementGenerator.cs

@@ -10,25 +10,15 @@ namespace Strata.SqlTools.Markdown.LinqToSql;
 /// </summary>
 public class SqlStatementGenerator
 {
-    private readonly SqlServer.SqlStatementGenerator _baseGenerator;
-
-    /// <summary>
-    /// Initializes a new instance of the SqlStatementGenerator class.
-    /// </summary>
-    public SqlStatementGenerator()
-    {
-        _baseGenerator = new SqlServer.SqlStatementGenerator();
-    }
-
     /// <summary>
     /// Generates a Mermaid sequence diagram showing LINQ to SQL statement execution flow.
     /// </summary>
     /// <param name="sqlBreakdown">The LINQ to SQL breakdown object.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid sequence diagram markdown.</returns>
-    public string GenerateSequenceDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
+    public static string GenerateSequenceDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
     {
-        return _baseGenerator.GenerateSequenceDiagram(sqlBreakdown, title);
+        return SqlServer.SqlStatementGenerator.GenerateSequenceDiagram(sqlBreakdown, title);
     }
 
     /// <summary>
@@ -37,7 +27,7 @@ public class SqlStatementGenerator
     /// <param name="sqlBreakdown">The SQL breakdown containing query information.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid ER diagram markdown.</returns>
-    public string GenerateEntityRelationshipDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
+    public static string GenerateEntityRelationshipDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
     {
         //Extract table names from breakdown - just use FROM clause for now
         var queryBreakdown = sqlBreakdown as IQueryBreakdown;
@@ -49,7 +39,7 @@ public class SqlStatementGenerator
             tableNames.Add(fromClauseText);
         }
 
-        return _baseGenerator.GenerateEntityRelationshipDiagram(tableNames, title);
+        return SqlServer.SqlStatementGenerator.GenerateEntityRelationshipDiagram(tableNames, title);
     }
 
     /// <summary>

src/Strata.SqlTools.Markdown/PostgreSql/QueryBreakdownGenerator.cs

@@ -8,26 +8,16 @@ namespace Strata.SqlTools.Markdown.PostgreSql;
 /// </summary>
 public class QueryBreakdownGenerator
 {
-    private readonly SqlServer.QueryBreakdownGenerator _baseGenerator;
-
-    /// <summary>
-    /// Initializes a new instance of the QueryBreakdownGenerator class.
-    /// </summary>
-    public QueryBreakdownGenerator()
-    {
-        _baseGenerator = new SqlServer.QueryBreakdownGenerator();
-    }
-
     /// <summary>
     /// Generates a Mermaid flowchart diagram from a PostgreSQL QueryBreakdown.
     /// </summary>
     /// <param name="queryBreakdown">The PostgreSQL QueryBreakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown diagram.</returns>
-    public string GenerateMermaidDiagram(QueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateMermaidDiagram(QueryBreakdown queryBreakdown, string? title = null)
     {
         // Since PostgreSql.QueryBreakdown inherits from SqlServer.QueryBreakdown,
         // we can use the base generator which works with the shared properties
-        return _baseGenerator.GenerateMermaidDiagram(queryBreakdown, title);
+        return SqlServer.QueryBreakdownGenerator.GenerateMermaidDiagram(queryBreakdown, title);
     }
 }

src/Strata.SqlTools.Markdown/PostgreSql/SqlStatementGenerator.cs

@@ -8,25 +8,15 @@ namespace Strata.SqlTools.Markdown.PostgreSql;
 /// </summary>
 public class SqlStatementGenerator
 {
-    private readonly SqlServer.SqlStatementGenerator _baseGenerator;
-
-    /// <summary>
-    /// Initializes a new instance of the SqlStatementGenerator class.
-    /// </summary>
-    public SqlStatementGenerator()
-    {
-        _baseGenerator = new SqlServer.SqlStatementGenerator();
-    }
-
     /// <summary>
     /// Generates a Mermaid sequence diagram showing PostgreSQL SQL statement execution flow.
     /// </summary>
     /// <param name="sqlBreakdown">The PostgreSQL SQL breakdown object.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid sequence diagram markdown.</returns>
-    public string GenerateSequenceDiagram(SqlBreakdownBase sqlBreakdown, string? title = null)
+    public static string GenerateSequenceDiagram(SqlBreakdownBase sqlBreakdown, string? title = null)
     {
-        return _baseGenerator.GenerateSequenceDiagram(sqlBreakdown, title);
+        return SqlServer.SqlStatementGenerator.GenerateSequenceDiagram(sqlBreakdown, title);
     }
 
     /// <summary>
@@ -35,8 +25,8 @@ public class SqlStatementGenerator
     /// <param name="tables">Collection of table names to include in the diagram.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid ER diagram markdown.</returns>
-    public string GenerateEntityRelationshipDiagram(IEnumerable<string> tables, string? title = null)
+    public static string GenerateEntityRelationshipDiagram(IEnumerable<string> tables, string? title = null)
     {
-        return _baseGenerator.GenerateEntityRelationshipDiagram(tables, title);
+        return SqlServer.SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables, title);
     }
 }

src/Strata.SqlTools.Markdown/Snowflake/QueryBreakdownGenerator.cs

@@ -8,26 +8,16 @@ namespace Strata.SqlTools.Markdown.Snowflake;
 /// </summary>
 public class QueryBreakdownGenerator
 {
-    private readonly SqlServer.QueryBreakdownGenerator _baseGenerator;
-
-    /// <summary>
-    /// Initializes a new instance of the QueryBreakdownGenerator class.
-    /// </summary>
-    public QueryBreakdownGenerator()
-    {
-        _baseGenerator = new SqlServer.QueryBreakdownGenerator();
-    }
-
     /// <summary>
     /// Generates a Mermaid flowchart diagram from a Snowflake QueryBreakdown.
     /// </summary>
     /// <param name="queryBreakdown">The Snowflake QueryBreakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown diagram.</returns>
-    public string GenerateMermaidDiagram(QueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateMermaidDiagram(QueryBreakdown queryBreakdown, string? title = null)
     {
         // Since Snowflake.QueryBreakdown inherits from SqlServer.QueryBreakdown,
         // we can use the base generator which works with the shared properties
-        return _baseGenerator.GenerateMermaidDiagram(queryBreakdown, title);
+        return SqlServer.QueryBreakdownGenerator.GenerateMermaidDiagram(queryBreakdown, title);
     }
 }

src/Strata.SqlTools.Markdown/Snowflake/SqlStatementGenerator.cs

@@ -8,25 +8,15 @@ namespace Strata.SqlTools.Markdown.Snowflake;
 /// </summary>
 public class SqlStatementGenerator
 {
-    private readonly SqlServer.SqlStatementGenerator _baseGenerator;
-
-    /// <summary>
-    /// Initializes a new instance of the SqlStatementGenerator class.
-    /// </summary>
-    public SqlStatementGenerator()
-    {
-        _baseGenerator = new SqlServer.SqlStatementGenerator();
-    }
-
     /// <summary>
     /// Generates a Mermaid sequence diagram showing Snowflake SQL statement execution flow.
     /// </summary>
     /// <param name="sqlBreakdown">The Snowflake SQL breakdown object.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid sequence diagram markdown.</returns>
-    public string GenerateSequenceDiagram(SqlBreakdownBase sqlBreakdown, string? title = null)
+    public static string GenerateSequenceDiagram(SqlBreakdownBase sqlBreakdown, string? title = null)
     {
-        return _baseGenerator.GenerateSequenceDiagram(sqlBreakdown, title);
+        return SqlServer.SqlStatementGenerator.GenerateSequenceDiagram(sqlBreakdown, title);
     }
 
     /// <summary>
@@ -35,8 +25,8 @@ public class SqlStatementGenerator
     /// <param name="tables">Collection of table names to include in the diagram.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid ER diagram markdown.</returns>
-    public string GenerateEntityRelationshipDiagram(IEnumerable<string> tables, string? title = null)
+    public static string GenerateEntityRelationshipDiagram(IEnumerable<string> tables, string? title = null)
     {
-        return _baseGenerator.GenerateEntityRelationshipDiagram(tables, title);
+        return SqlServer.SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables, title);
     }
 }

src/Strata.SqlTools.Markdown/SqlServer/QueryBreakdownGenerator.cs

@@ -16,7 +16,7 @@ public class QueryBreakdownGenerator
     /// <param name="queryBreakdown">The QueryBreakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown diagram.</returns>
-    public string GenerateMermaidDiagram(QueryBreakdown queryBreakdown, string? title = null)
+    public static string GenerateMermaidDiagram(QueryBreakdown queryBreakdown, string? title = null)
     {
         var sb = new StringBuilder();
 
@@ -127,7 +127,7 @@ public class QueryBreakdownGenerator
     /// <param name="sqlBreakdown">The SQL breakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown diagram.</returns>
-    public string GenerateMermaidDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
+    public static string GenerateMermaidDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
     {
         // If it's a QueryBreakdown, use the specialized method
         if (sqlBreakdown is QueryBreakdown qb)

src/Strata.SqlTools.Markdown/SqlServer/SqlStatementGenerator.cs

@@ -14,7 +14,7 @@ public class SqlStatementGenerator
     /// <param name="sqlBreakdown">The SQL breakdown to visualize.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown sequence diagram.</returns>
-    public string GenerateSequenceDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
+    public static string GenerateSequenceDiagram(ISqlBreakdown sqlBreakdown, string? title = null)
     {
         var sb = new StringBuilder();
 
@@ -74,7 +74,7 @@ public class SqlStatementGenerator
     /// <param name="tableNames">List of table names referenced in the query.</param>
     /// <param name="title">Optional title for the diagram.</param>
     /// <returns>A string containing the Mermaid markdown ER diagram.</returns>
-    public string GenerateEntityRelationshipDiagram(IEnumerable<string> tableNames, string? title = null)
+    public static string GenerateEntityRelationshipDiagram(IEnumerable<string> tableNames, string? title = null)
     {
         var sb = new StringBuilder();
 

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.
     /// </summary>
     /// <typeparam name="T">The entity type for the query.</typeparam>
-    /// <returns>null by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.</returns>
+    /// <returns>An empty queryable by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.</returns>
     /// <remarks>
-    /// 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.
     /// </remarks>
-    public override IQueryable<T>? GetQuery<T>() 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<T> GetQuery<T>() where T : class => Enumerable.Empty<T>().AsQueryable();
 }
 
 

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.
     /// </summary>
     /// <typeparam name="T">The entity type for the query.</typeparam>
-    /// <returns>null by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.</returns>
+    /// <returns>An empty queryable by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.</returns>
     /// <remarks>
-    /// 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.
     /// </remarks>
-    public override IQueryable<T>? GetQuery<T>() 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<T> GetQuery<T>() where T : class => Enumerable.Empty<T>().AsQueryable();
 }
 
 

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.
     /// </summary>
     /// <typeparam name="T">The entity type for the query.</typeparam>
-    /// <returns>An IQueryable of the specified type, or null if the breakdown cannot be converted to a LINQ query.</returns>
+    /// <returns>An IQueryable of the specified type; an empty queryable if the breakdown cannot be converted to a LINQ query.</returns>
     /// <remarks>
     /// 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.
     /// </remarks>
-    public virtual IQueryable<T>? GetQuery<T>() where T : class => null;
+    public virtual IQueryable<T> GetQuery<T>() where T : class => Enumerable.Empty<T>().AsQueryable();
 
     /// <summary>
     /// Gets the complete SQL query including optional setup and finish clauses.

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.
     /// </summary>
     /// <typeparam name="T">The entity type for the query.</typeparam>
-    /// <returns>null by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.</returns>
+    /// <returns>An empty queryable by default, as QueryBreakdown operates on SQL. Override in derived classes to provide LINQ query reconstruction.</returns>
     /// <remarks>
-    /// 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.
     /// </remarks>
-    public override IQueryable<T>? GetQuery<T>() 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<T> GetQuery<T>() where T : class => Enumerable.Empty<T>().AsQueryable();
 
     /// <summary>
     /// Gets the complete SQL query string (interface implementation).

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<User>();
 
         // 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<User>();
 
         // 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);
         });
     }
 

tests/Strata.SqlTools.Markdown.Tests/LinqToSql/QueryBreakdownGeneratorTests.cs

@@ -24,7 +24,7 @@ public class QueryBreakdownGeneratorTests
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(breakdown, "Simple User Query");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(breakdown, "Simple User Query");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -81,7 +81,7 @@ public class QueryBreakdownGeneratorTests
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
-        var result = _generator.GenerateCombinedDiagram(breakdown, "User Query Analysis");
+        var result = QueryBreakdownGenerator.GenerateCombinedDiagram(breakdown, "User Query Analysis");
 
         // Assert
         Assert.That(result, Does.Contain("## User Query Analysis"));
@@ -99,7 +99,7 @@ public class QueryBreakdownGeneratorTests
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(breakdown);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(breakdown);
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -114,7 +114,7 @@ public class QueryBreakdownGeneratorTests
         var breakdown = LinqQueryBreakdown.Analyze(query);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(breakdown, null);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(breakdown, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));

tests/Strata.SqlTools.Markdown.Tests/LinqToSql/SqlStatementGeneratorTests.cs

@@ -87,7 +87,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, "Sequence Test");
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, "Sequence Test");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -102,7 +102,7 @@ public class SqlStatementGeneratorTests
         var query = new LinqQueryBreakdown("Id, Name", "Users");
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(query, "ER Test");
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(query, "ER Test");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));

tests/Strata.SqlTools.Markdown.Tests/PostgreSql/QueryBreakdownGeneratorTests.cs

@@ -21,7 +21,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("user_id, user_name", "users");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Simple User Query");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Simple User Query");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -44,7 +44,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("WHERE"));
@@ -64,7 +64,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("WHERE"));
@@ -89,7 +89,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Users with Orders");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Users with Orders");
 
         // Assert
         Assert.That(result, Does.Contain("### Users with Orders"));
@@ -110,7 +110,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Recent Users");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Recent Users");
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -131,7 +131,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -150,7 +150,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -185,7 +185,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Regional Sales Analysis");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Regional Sales Analysis");
 
         // Assert
         Assert.That(result, Does.Contain("### Regional Sales Analysis"));
@@ -209,7 +209,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("GROUP BY"));
@@ -223,7 +223,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("id", "orders");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, null);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));
@@ -238,7 +238,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("order_id", "orders");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "");
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));
@@ -258,7 +258,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Type Cast Example");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Type Cast Example");
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -279,7 +279,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "JSON Data");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "JSON Data");
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -298,7 +298,7 @@ public class QueryBreakdownGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));

tests/Strata.SqlTools.Markdown.Tests/PostgreSql/SqlStatementGeneratorTests.cs

@@ -25,7 +25,7 @@ public class SqlStatementGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, "User Query Flow");
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, "User Query Flow");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -51,7 +51,7 @@ public class SqlStatementGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Execute Main Statement"));
@@ -73,7 +73,7 @@ public class SqlStatementGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, "Sales Analysis");
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, "Sales Analysis");
 
         // Assert
         Assert.That(result, Does.Contain("### Sales Analysis"));
@@ -90,7 +90,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "customers", "orders", "order_items", "products" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables, "E-Commerce Schema");
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables, "E-Commerce Schema");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -109,7 +109,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "\"Customers\"", "\"Orders\"", "\"OrderItems\"" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("erDiagram"));
@@ -123,7 +123,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "public.users", "sales.orders", "inventory.products" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("erDiagram"));
@@ -137,7 +137,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "users" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("erDiagram"));
@@ -151,7 +151,7 @@ public class SqlStatementGeneratorTests
         var query = new QueryBreakdown("order_id", "orders");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, null);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));
@@ -170,7 +170,7 @@ public class SqlStatementGeneratorTests
         ");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("sequenceDiagram"));

tests/Strata.SqlTools.Markdown.Tests/Snowflake/QueryBreakdownGeneratorTests.cs

@@ -21,7 +21,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("USER_ID, USER_NAME", "USERS");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Simple User Query");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Simple User Query");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -44,7 +44,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("WHERE"));
@@ -69,7 +69,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Users with Orders");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Users with Orders");
 
         // Assert
         Assert.That(result, Does.Contain("WITH Clause"));
@@ -92,7 +92,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Latest Orders per Customer");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Latest Orders per Customer");
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -111,7 +111,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -146,7 +146,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Regional Sales Analysis");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Regional Sales Analysis");
 
         // Assert
         Assert.That(result, Does.Contain("### Regional Sales Analysis"));
@@ -171,7 +171,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("GROUP BY"));
@@ -185,7 +185,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("ID", "ORDERS");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, null);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));
@@ -200,7 +200,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("ORDER_ID", "ORDERS");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "");
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));
@@ -220,7 +220,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Type Cast Example");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Type Cast Example");
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));
@@ -241,7 +241,7 @@ public class QueryBreakdownGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "JSON Data");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "JSON Data");
 
         // Assert
         Assert.That(result, Does.Contain("SELECT"));

tests/Strata.SqlTools.Markdown.Tests/Snowflake/SqlStatementGeneratorTests.cs

@@ -25,7 +25,7 @@ public class SqlStatementGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, "User Query Flow");
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, "User Query Flow");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -51,7 +51,7 @@ public class SqlStatementGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Execute Main Statement"));
@@ -73,7 +73,7 @@ public class SqlStatementGeneratorTests
         ", isMicrosoftSql: false);
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, "Sales Analysis");
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, "Sales Analysis");
 
         // Assert
         Assert.That(result, Does.Contain("### Sales Analysis"));
@@ -90,7 +90,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "CUSTOMERS", "ORDERS", "ORDER_ITEMS", "PRODUCTS" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables, "E-Commerce Schema");
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables, "E-Commerce Schema");
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -109,7 +109,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "\"customers\"", "\"orders\"", "\"orderItems\"" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("erDiagram"));
@@ -123,7 +123,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "USERS" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("erDiagram"));
@@ -137,7 +137,7 @@ public class SqlStatementGeneratorTests
         var query = new QueryBreakdown("ORDER_ID", "ORDERS");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, null);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, null);
 
         // Assert
         Assert.That(result, Does.Not.Contain("###"));

tests/Strata.SqlTools.Markdown.Tests/SqlServer/QueryBreakdownGeneratorTests.cs

@@ -22,7 +22,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("ID, Name", "Users");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -46,7 +46,7 @@ public class QueryBreakdownGeneratorTests
         query.OrderByClause.Clause = "OrderCount DESC";
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "User Orders Query");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "User Orders Query");
 
         // Assert
         Assert.That(result, Does.Contain("### User Orders Query"));
@@ -65,7 +65,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("*", "Products", "Price > 100");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("WHERE"));
@@ -86,7 +86,7 @@ public class QueryBreakdownGeneratorTests
         var query = QueryBreakdown.Parse(sql);
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Is.Not.Null);
@@ -102,7 +102,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query, "Test Query");
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query, "Test Query");
 
         // Assert
         Assert.That(result, Does.StartWith("### Test Query"));
@@ -115,7 +115,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Not.StartWith("###"));
@@ -130,7 +130,7 @@ public class QueryBreakdownGeneratorTests
         var query = new QueryBreakdown(longSelect, "LargeTable");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram(query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("..."));
@@ -144,7 +144,7 @@ public class QueryBreakdownGeneratorTests
         query.SetupClauses.Add("CREATE TEMP TABLE #Temp (ID INT)");
 
         // Act
-        var result = _generator.GenerateMermaidDiagram((Interfaces.ISqlBreakdown)query);
+        var result = QueryBreakdownGenerator.GenerateMermaidDiagram((Interfaces.ISqlBreakdown)query);
 
         // Assert
         Assert.That(result, Does.Contain("mermaid"));

tests/Strata.SqlTools.Markdown.Tests/SqlServer/QueryMarkdownGenerationTests.cs

@@ -59,7 +59,7 @@ public class QueryMarkdownGenerationTests
                 var queryBreakdown = QueryBreakdown.Parse(sqlContent);
 
                 // Generate markdown with the filename as title
-                var markdown = _generator.GenerateMermaidDiagram(queryBreakdown, fileName);
+                var markdown = QueryBreakdownGenerator.GenerateMermaidDiagram(queryBreakdown, fileName);
 
                 // Verify markdown was generated
                 Assert.That(markdown, Is.Not.Null);
@@ -107,7 +107,7 @@ public class QueryMarkdownGenerationTests
             try
             {
                 var queryBreakdown = QueryBreakdown.Parse(sqlContent);
-                var markdown = _generator.GenerateMermaidDiagram(queryBreakdown, fileName);
+                var markdown = QueryBreakdownGenerator.GenerateMermaidDiagram(queryBreakdown, fileName);
 
                 // Add source SQL to the markdown
                 var fullMarkdown = $"{markdown}\n\n## Source SQL\n\n```sql\n{sqlContent}\n```\n";

tests/Strata.SqlTools.Markdown.Tests/SqlServer/SqlStatementGeneratorTests.cs

@@ -21,7 +21,7 @@ public class SqlStatementGeneratorTests
         var query = new QueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -39,7 +39,7 @@ public class SqlStatementGeneratorTests
         query.SetupClauses.Add("CREATE TEMP TABLE #Temp (ID INT)");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Setup Clauses"));
@@ -55,7 +55,7 @@ public class SqlStatementGeneratorTests
         query.FinishClauses.Add("DROP TABLE #Temp");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query);
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query);
 
         // Assert
         Assert.That(result, Does.Contain("Finish Clauses"));
@@ -69,7 +69,7 @@ public class SqlStatementGeneratorTests
         var query = new QueryBreakdown("*", "Users");
 
         // Act
-        var result = _generator.GenerateSequenceDiagram(query, "Query Execution");
+        var result = SqlStatementGenerator.GenerateSequenceDiagram(query, "Query Execution");
 
         // Assert
         Assert.That(result, Does.StartWith("### Query Execution"));
@@ -82,7 +82,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "Users", "Orders", "Products" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("```mermaid"));
@@ -100,7 +100,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "Users", "Orders" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables, "Database Schema");
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables, "Database Schema");
 
         // Assert
         Assert.That(result, Does.StartWith("### Database Schema"));
@@ -113,7 +113,7 @@ public class SqlStatementGeneratorTests
         var tables = new[] { "[dbo].[Users]", "schema.Orders" };
 
         // Act
-        var result = _generator.GenerateEntityRelationshipDiagram(tables);
+        var result = SqlStatementGenerator.GenerateEntityRelationshipDiagram(tables);
 
         // Assert
         Assert.That(result, Does.Contain("dbo_Users"));