Support dropping foreign key

go.mod

@@ -5,7 +5,7 @@ go 1.17
 require (
 	github.com/go-rel/primaryreplica v0.4.0
 	github.com/go-rel/rel v0.39.0
-	github.com/go-rel/sql v0.13.1
+	github.com/go-rel/sql v0.13.2-0.20230704013859-dd905c4be623
 	github.com/go-sql-driver/mysql v1.6.0
 	github.com/stretchr/testify v1.8.3
 )

go.sum

@@ -12,6 +12,8 @@ github.com/go-rel/rel v0.39.0 h1:2zmK8kazM82iRRfWX7+mm1MxDkGKDj2W+xJLjguli5U=
 github.com/go-rel/rel v0.39.0/go.mod h1:yN6+aimHyRIzbuWFe5DaxiZPuVuPfd7GlLpy/YTqTUg=
 github.com/go-rel/sql v0.13.1 h1:Q3G9/QyK4p7AIDNviW0x3JrfdG5LyoLrGH9uoaUtA+o=
 github.com/go-rel/sql v0.13.1/go.mod h1:3t/E+2E/Y9rXURDD7ZMgpFdXLji10gP7gb57HeoaRNY=
+github.com/go-rel/sql v0.13.2-0.20230704013859-dd905c4be623 h1:Qv+LecXM6dyy4B7r9icdF8OJA+kD8nPFX4s6W8mUMLk=
+github.com/go-rel/sql v0.13.2-0.20230704013859-dd905c4be623/go.mod h1:KQJuW3s+GDnwdgA3+Ic5awz9t259bVehS4nd5A+Vgic=
 github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=

mysql.go

@@ -1,6 +1,7 @@
 // Package mysql wraps mysql driver as an adapter for REL.
 //
 // Usage:
+//
 //	// open mysql connection.
 //	// note: `clientFoundRows=true` is required for update and delete to works correctly.
 //	adapter, err := mysql.Open("root@(127.0.0.1:3306)/rel_test?clientFoundRows=true&charset=utf8&parseTime=True&loc=Local")
@@ -15,6 +16,7 @@ package mysql
 
 import (
 	db "database/sql"
+	"fmt"
 	"strings"
 
 	"github.com/go-rel/rel"
@@ -36,7 +38,7 @@ func New(database *db.DB) rel.Adapter {
 		deleteBuilder     = builder.Delete{BufferFactory: bufferFactory, Query: queryBuilder, Filter: filterBuilder}
 		ddlBufferFactory  = builder.BufferFactory{InlineValues: true, BoolTrueValue: "true", BoolFalseValue: "false", Quoter: Quote{}, ValueConverter: ValueConvert{}}
 		ddlQueryBuilder   = builder.Query{BufferFactory: ddlBufferFactory, Filter: filterBuilder}
-		tableBuilder      = builder.Table{BufferFactory: ddlBufferFactory, ColumnMapper: columnMapper}
+		tableBuilder      = builder.Table{BufferFactory: ddlBufferFactory, ColumnMapper: columnMapper, DropKeyMapper: dropKeyMapper}
 		indexBuilder      = builder.Index{BufferFactory: ddlBufferFactory, Query: ddlQueryBuilder, Filter: filterBuilder, DropIndexOnTable: true}
 	)
 
@@ -137,6 +139,14 @@ func columnMapper(column *rel.Column) (string, int, int) {
 	}
 }
 
+func dropKeyMapper(typ rel.KeyType) string {
+	if typ == rel.ForeignKey {
+		return "FOREIGN KEY"
+	}
+
+	panic(fmt.Sprintf("drop key: unsupported key type `%s`", typ))
+}
+
 func check(err error) {
 	if err != nil {
 		panic(err)

mysql_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/go-rel/primaryreplica"
 	"github.com/go-rel/rel"
+	"github.com/go-rel/sql"
 	"github.com/go-rel/sql/specs"
 	_ "github.com/go-sql-driver/mysql"
 	"github.com/stretchr/testify/assert"
@@ -163,3 +164,56 @@ func TestCheck(t *testing.T) {
 		check(errors.New("error"))
 	})
 }
+
+func TestAdapter_TableBuilder(t *testing.T) {
+	adapter, err := Open(dsn())
+	assert.Nil(t, err)
+	defer adapter.Close()
+
+	tests := []struct {
+		result string
+		table  rel.Table
+	}{
+		{
+			result: "ALTER TABLE `table` DROP FOREIGN KEY `fk`;",
+			table: rel.Table{
+				Op:   rel.SchemaAlter,
+				Name: "table",
+				Definitions: []rel.TableDefinition{
+					rel.Key{Op: rel.SchemaDrop, Name: "fk", Type: rel.ForeignKey},
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.result, func(t *testing.T) {
+			assert.Equal(t, test.result, adapter.(*sql.SQL).TableBuilder.Build(test.table))
+		})
+	}
+}
+
+func TestAdapter_TableBuilder_unsupportedDropKeyType(t *testing.T) {
+	adapter, err := Open(dsn())
+	assert.Nil(t, err)
+	defer adapter.Close()
+
+	tests := []rel.KeyType{
+		rel.PrimaryKey,
+		rel.UniqueKey,
+	}
+
+	for _, keyType := range tests {
+		t.Run(string(keyType), func(t *testing.T) {
+			table := rel.Table{
+				Op:   rel.SchemaAlter,
+				Name: "table",
+				Definitions: []rel.TableDefinition{
+					rel.Key{Op: rel.SchemaDrop, Name: "fk", Type: keyType},
+				},
+			}
+
+			assert.Panics(t, func() { adapter.(*sql.SQL).TableBuilder.Build(table) })
+		})
+	}
+}