manage TDS_DATA_COLUMNSTATUS in ValueReader

src/AdoNetCore.AseClient/Enum/TdsDataColumnStatus.cs

@@ -0,0 +1,22 @@
+using System;
+// ReSharper disable InconsistentNaming
+
+namespace AdoNetCore.AseClient.Enum
+{
+    [Flags]
+    internal enum TdsDataColumnStatus : byte
+    {
+        /// <summary>
+        /// No Data follows, the value is NULL.
+        /// </summary>
+        TDS_DATA_COLUMNSTATUS_NO_DATA = 0x01,
+        /// <summary>
+        /// This data value is corrupted due to Overflow/Underflow.
+        /// </summary>
+        TDS_DATA_COLUMNSTATUS_CORRUPTED = 0x02,
+        /// <summary>
+        /// This data value has been truncated or rounded.
+        /// </summary>
+        TDS_DATA_COLUMNSTATUS_TRUNCATED = 0x04,
+    }
+}

src/AdoNetCore.AseClient/Internal/ValueReader.cs

@@ -61,6 +61,15 @@ private static object ReadInternal(Stream stream, FormatItem format, DbEnvironme
         {
             if (ReadMap.ContainsKey(format.DataType))
             {
+                // If the TDS_DATA_COLUMNSTATUS request capability is enabled, then all datatype representations begin with a status byte
+                if (format.RowStatus.HasFlag(RowFormatItemStatus.TDS_ROW_COLUMNSTATUS))
+                {
+                    var columnStatus = (TdsDataColumnStatus)stream.ReadByte();
+                    if (columnStatus.HasFlag(TdsDataColumnStatus.TDS_DATA_COLUMNSTATUS_NO_DATA))
+                    {
+                        return DBNull.Value;
+                    }
+                }
                 return ReadMap[format.DataType](stream, format, env) ?? DBNull.Value;
             }