From b474d179ccf4972d16ab3b66bd619ddff5b2e8c1 Mon Sep 17 00:00:00 2001
From: Roman <covrom@gmail.com>
Date: Fri, 3 Sep 2021 11:11:55 +0300
Subject: [PATCH] fix DROP CONSTRAINT

---
 cmd/goerd/main.go | 15 ++++++++++-----
 schema/diff.go    |  5 ++++-
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/cmd/goerd/main.go b/cmd/goerd/main.go
index dd0c61e..d330b19 100644
--- a/cmd/goerd/main.go
+++ b/cmd/goerd/main.go
@@ -67,7 +67,8 @@ func main() {
 						fmt.Println("--", q)
 						continue
 					}
-					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") {
+					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") ||
+						strings.Contains(strings.ToUpper(q), "DROP CONSTRAINT") {
 						fmt.Println("--", q)
 						continue
 					}
@@ -129,7 +130,8 @@ func main() {
 						fmt.Println("--", q)
 						continue
 					}
-					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") {
+					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") ||
+						strings.Contains(strings.ToUpper(q), "DROP CONSTRAINT") {
 						fmt.Println("--", q)
 						continue
 					}
@@ -151,7 +153,8 @@ func main() {
 						fmt.Println("--", q)
 						continue
 					}
-					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") {
+					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") ||
+						strings.Contains(strings.ToUpper(q), "DROP CONSTRAINT") {
 						fmt.Println("--", q)
 						continue
 					}
@@ -224,7 +227,8 @@ func main() {
 						fmt.Println("--", q)
 						continue
 					}
-					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") {
+					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") ||
+						strings.Contains(strings.ToUpper(q), "DROP CONSTRAINT") {
 						fmt.Println("--", q)
 						continue
 					}
@@ -246,7 +250,8 @@ func main() {
 						fmt.Println("--", q)
 						continue
 					}
-					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") {
+					if strings.Contains(strings.ToUpper(q), "DROP COLUMN") ||
+						strings.Contains(strings.ToUpper(q), "DROP CONSTRAINT") {
 						fmt.Println("--", q)
 						continue
 					}
diff --git a/schema/diff.go b/schema/diff.go
index d0b9ce3..6d14838 100644
--- a/schema/diff.go
+++ b/schema/diff.go
@@ -315,7 +315,10 @@ func (c *PatchConstraint) alter() []string {
 }
 
 func (c *PatchConstraint) drop() []string {
-	// always drop unused constraints
+	if c.to == nil && c.from.Type == TypePK {
+		// pk not drop
+		return nil
+	}
 	return []string{
 		fmt.Sprintf("ALTER TABLE %s DROP CONSTRAINT IF EXISTS %s", c.tableName, c.from.Name),
 	}