From 7cdf44376b00525c69e9a2bbc4fe934f629a76dd Mon Sep 17 00:00:00 2001
From: Aaron L <aaron@bettercoder.net>
Date: Tue, 12 Jul 2016 08:09:26 -0700
Subject: [PATCH] Add even more nullable things for FKeys.

---
 bdb/interface.go      | 26 +++++++++++---------------
 bdb/interface_test.go | 41 ++++++++++++++++++++++++++++-------------
 bdb/keys.go           |  5 +++--
 3 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/bdb/interface.go b/bdb/interface.go
index af02bf8..3ab738d 100644
--- a/bdb/interface.go
+++ b/bdb/interface.go
@@ -52,11 +52,15 @@ func Tables(db Interface, names ...string) ([]Table, error) {
 		}
 
 		setIsJoinTable(&t)
-		setForeignKeyNullability(&t)
 
 		tables = append(tables, t)
 	}
 
+	// Relationships have a dependency on foreign key nullability.
+	for i := range tables {
+		tbl := &tables[i]
+		setForeignKeyNullability(tbl, tables)
+	}
 	for i := range tables {
 		tbl := &tables[i]
 		setRelationships(tbl, tables)
@@ -89,22 +93,14 @@ func setIsJoinTable(t *Table) {
 	t.IsJoinTable = true
 }
 
-func setForeignKeyNullability(t *Table) {
+func setForeignKeyNullability(t *Table, tables []Table) {
 	for i, fkey := range t.FKeys {
+		localColumn := t.GetColumn(fkey.Column)
+		foreignTable := GetTable(tables, fkey.ForeignTable)
+		foreignColumn := foreignTable.GetColumn(fkey.ForeignColumn)
 
-		found := -1
-		for j, col := range t.Columns {
-			if col.Name == fkey.Column {
-				found = j
-				break
-			}
-		}
-
-		if found < 0 {
-			panic("could not find foreign key column in table")
-		}
-
-		t.FKeys[i].Nullable = t.Columns[found].Nullable
+		t.FKeys[i].Nullable = localColumn.Nullable
+		t.FKeys[i].ForeignColumnNullable = foreignColumn.Nullable
 	}
 }
 
diff --git a/bdb/interface_test.go b/bdb/interface_test.go
index 71ea60a..d8fae8b 100644
--- a/bdb/interface_test.go
+++ b/bdb/interface_test.go
@@ -128,27 +128,42 @@ func TestSetIsJoinTable(t *testing.T) {
 func TestSetForeignKeyNullability(t *testing.T) {
 	t.Parallel()
 
-	table := &Table{
-		Columns: []Column{
-			Column{Name: "col1", Type: "string"},
-			Column{Name: "col2", Type: "string", Nullable: true},
-		},
-		FKeys: []ForeignKey{
-			{
-				Column: "col1",
+	tables := []Table{
+		Table{
+			Name: "one",
+			Columns: []Column{
+				Column{Name: "id1", Type: "string", Nullable: false},
+				Column{Name: "id2", Type: "string", Nullable: true},
 			},
-			{
-				Column: "col2",
+		},
+		Table{
+			Name: "other",
+			Columns: []Column{
+				Column{Name: "one_id_1", Type: "string", Nullable: false},
+				Column{Name: "one_id_2", Type: "string", Nullable: true},
+			},
+			FKeys: []ForeignKey{
+				{Column: "one_id_1", ForeignTable: "one", ForeignColumn: "id1"},
+				{Column: "one_id_2", ForeignTable: "one", ForeignColumn: "id2"},
 			},
 		},
 	}
 
-	setForeignKeyNullability(table)
+	setForeignKeyNullability(&tables[0], tables)
+	setForeignKeyNullability(&tables[1], tables)
 
-	if table.FKeys[0].Nullable {
+	first := tables[1].FKeys[0]
+	second := tables[1].FKeys[1]
+	if first.Nullable {
 		t.Error("should not be nullable")
 	}
-	if !table.FKeys[1].Nullable {
+	if first.ForeignColumnNullable {
+		t.Error("should be nullable")
+	}
+	if !second.Nullable {
+		t.Error("should be nullable")
+	}
+	if !second.ForeignColumnNullable {
 		t.Error("should be nullable")
 	}
 }
diff --git a/bdb/keys.go b/bdb/keys.go
index b5ff526..d3c672a 100644
--- a/bdb/keys.go
+++ b/bdb/keys.go
@@ -20,8 +20,9 @@ type ForeignKey struct {
 	Column   string
 	Nullable bool
 
-	ForeignTable  string
-	ForeignColumn string
+	ForeignTable          string
+	ForeignColumn         string
+	ForeignColumnNullable bool
 }
 
 // SQLColumnDef formats a column name and type like an SQL column definition.