diff --git a/DbFirst.API/Controllers/CatalogsController.cs b/DbFirst.API/Controllers/CatalogsController.cs
index d94cec4..82c6307 100644
--- a/DbFirst.API/Controllers/CatalogsController.cs
+++ b/DbFirst.API/Controllers/CatalogsController.cs
@@ -50,13 +50,14 @@ public class CatalogsController : ControllerBase
         return NoContent();
     }
 
-    [HttpPut("sp")]
-    public async Task<ActionResult<CatalogDto>> UpdateWithStoredProcedure(CatalogDto dto, CancellationToken cancellationToken)
+    [HttpPut("sp/{id:int}")]
+    public async Task<ActionResult<CatalogDto>> UpdateWithStoredProcedure(int id, CatalogDto dto, CancellationToken cancellationToken)
     {
+        dto.Guid = id;
         var updated = await _service.UpdateWithStoredProcedureAsync(dto, cancellationToken);
         if (updated == null)
         {
-            return BadRequest();
+            return NotFound();
         }
         return Ok(updated);
     }
diff --git a/DbFirst.Infrastructure/Repositories/CatalogRepository.cs b/DbFirst.Infrastructure/Repositories/CatalogRepository.cs
index 7b66f0b..2e69fde 100644
--- a/DbFirst.Infrastructure/Repositories/CatalogRepository.cs
+++ b/DbFirst.Infrastructure/Repositories/CatalogRepository.cs
@@ -55,14 +55,18 @@ public class CatalogRepository : ICatalogRepository
 
     public async Task<Catalog?> UpdateWithStoredProcedureAsync(Catalog catalog, CancellationToken cancellationToken = default)
     {
-        // ensure the record exists by CAT_TITLE to avoid insert behavior of the SP
-        var exists = await _db.TbmyCatalogs.AsNoTracking().AnyAsync(x => x.CatTitle == catalog.CatTitle, cancellationToken);
-        if (!exists)
+        if (catalog.Guid == 0)
         {
             return null;
         }
 
-        var catTitleParam = new SqlParameter("@CAT_TITLE", catalog.CatTitle);
+        var existing = await _db.TbmyCatalogs.AsNoTracking().FirstOrDefaultAsync(x => x.Guid == catalog.Guid, cancellationToken);
+        if (existing == null)
+        {
+            return null;
+        }
+
+        var catTitleParam = new SqlParameter("@CAT_TITLE", existing.CatTitle);
         var catStringParam = new SqlParameter("@CAT_STRING", catalog.CatString);
         var changedWhoParam = new SqlParameter("@CHANGED_WHO", (object?)catalog.ChangedWho ?? DBNull.Value);
         var guidOutParam = new SqlParameter("@GUID", SqlDbType.Int) { Direction = ParameterDirection.Output };
@@ -79,7 +83,7 @@ public class CatalogRepository : ICatalogRepository
 
         var guid = (int)guidOutParam.Value;
         var entity = await _db.TbmyCatalogs.AsNoTracking().FirstOrDefaultAsync(x => x.Guid == guid, cancellationToken);
-        return entity == null ? new Catalog { Guid = guid, CatTitle = catalog.CatTitle, CatString = catalog.CatString, ChangedWho = catalog.ChangedWho } : _mapper.Map<Catalog>(entity);
+        return entity == null ? new Catalog { Guid = guid, CatTitle = existing.CatTitle, CatString = catalog.CatString, ChangedWho = catalog.ChangedWho } : _mapper.Map<Catalog>(entity);
     }
 
     public async Task<bool> DeleteAsync(int id, CancellationToken cancellationToken = default)