From faecdf353d00732572f38a776ff02a24520df893 Mon Sep 17 00:00:00 2001
From: Gwynne Raskind <gwynne@vapor.codes>
Date: Tue, 2 Aug 2022 16:35:36 -0500
Subject: [PATCH] Add locking clause syntax to dialect (#310)

Provide the correct MySQL syntax for SELECT locking clauses via the new SQLDialect properties.
---
 Sources/MySQLKit/MySQLDialect.swift | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Sources/MySQLKit/MySQLDialect.swift b/Sources/MySQLKit/MySQLDialect.swift
index 0a214f8..0753fe3 100644
--- a/Sources/MySQLKit/MySQLDialect.swift
+++ b/Sources/MySQLKit/MySQLDialect.swift
@@ -77,4 +77,12 @@ public struct MySQLDialect: SQLDialect {
     public var unionFeatures: SQLUnionFeatures {
         [.union, .unionAll, .explicitDistinct, .parenthesizedSubqueries]
     }
+    
+    public var sharedSelectLockExpression: SQLExpression? {
+        SQLRaw("LOCK IN SHARE MODE")
+    }
+    
+    public var exclusiveSelectLockExpression: SQLExpression? {
+        SQLRaw("FOR UPDATE")
+    }
 }