From 808116c88329954ce07280fb6caf12d60c5b59df Mon Sep 17 00:00:00 2001
From: emkael <emkael@tlen.pl>
Date: Sun, 30 Jul 2017 14:23:45 +0200
Subject: Sql.selectOne now can distinguish no value in result row from no
 result at all

---
 Aktywator/Sql.cs | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

(limited to 'Aktywator/Sql.cs')

diff --git a/Aktywator/Sql.cs b/Aktywator/Sql.cs
index c35b0dd..cf0eb38 100644
--- a/Aktywator/Sql.cs
+++ b/Aktywator/Sql.cs
@@ -7,6 +7,10 @@ using data = System.Data.OleDb.OleDbDataReader;
 
 namespace Aktywator
 {
+    class OleDbRowMissingException : Exception
+    {
+    }
+
     class Sql
     {
         private OleDbConnection connection;
@@ -34,12 +38,19 @@ namespace Aktywator
             OleDbCommand cmd = new OleDbCommand(q, connection);
             return cmd.ExecuteNonQuery();
         }
-        public string selectOne(string q)
+        public string selectOne(string q, bool checkForRow = false)
         {
             OleDbCommand cmd = new OleDbCommand(q, connection);
             object o = cmd.ExecuteScalar();
-            if (o == null) return "";
-            else return o.ToString();
+            if (o == null) // it's null if the row does not exist, it'd be DBNull.Value if NULL was the value in existing row
+            {
+                if (!checkForRow)
+                {
+                    return "";
+                }
+                throw new OleDbRowMissingException();
+            }
+            return o.ToString();
         }
         public data select(string q)
         {
-- 
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