diff --git a/compile.go b/compile.go
index d5c1ce2..9f2d10b 100644
--- a/compile.go
+++ b/compile.go
@@ -49,6 +49,10 @@ func (s *sqlite3Runtime) compileModule(ctx context.Context) {
 			return
 		}
 	}
+	if bin == nil {
+		s.err = binaryErr
+		return
+	}
 
 	s.compiled, s.err = s.runtime.CompileModule(ctx, bin)
 }
diff --git a/conn_test.go b/conn_test.go
index 41b27ca..f8832d4 100644
--- a/conn_test.go
+++ b/conn_test.go
@@ -40,6 +40,10 @@ func TestConn_Close_BUSY(t *testing.T) {
 	if rc := serr.Code(); rc != BUSY {
 		t.Errorf("got %d, want sqlite3.BUSY", rc)
 	}
+	var terr interface{ Temporary() bool }
+	if !errors.As(err, &terr) || !terr.Temporary() {
+		t.Error("not temporary", err)
+	}
 	if got := err.Error(); got != `sqlite3: database is locked: unable to close due to unfinalized statements or unfinished backups` {
 		t.Error("got message: ", got)
 	}
diff --git a/driver/driver.go b/driver/driver.go
index e20e790..85c2bfe 100644
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -26,14 +26,18 @@ func (sqlite) Open(name string) (driver.Conn, error) {
 		return nil, err
 	}
 
-	var txBegin = "BEGIN "
+	var txBegin string
 	var pragmas strings.Builder
 	if _, after, ok := strings.Cut(name, "?"); ok {
 		query, _ := url.ParseQuery(after)
 
-		switch v := query.Get("_txlock"); v {
+		switch s := query.Get("_txlock"); s {
+		case "":
+			txBegin = "BEGIN"
 		case "deferred", "immediate", "exclusive":
-			txBegin += v
+			txBegin = "BEGIN " + s
+		default:
+			return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", s)
 		}
 
 		for _, p := range query["_pragma"] {
@@ -219,6 +223,8 @@ func (s stmt) Query(args []driver.Value) (driver.Rows, error) {
 }
 
 func (s stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	// Use QueryContext to setup bindings.
+	// No need to close rows: that simply resets the statement, exec does the same.
 	_, err := s.QueryContext(ctx, args)
 	if err != nil {
 		return nil, err
diff --git a/driver/driver_test.go b/driver/driver_test.go
index 3d37f1f..aa1e285 100644
--- a/driver/driver_test.go
+++ b/driver/driver_test.go
@@ -78,7 +78,8 @@ func Test_Open_pragma_invalid(t *testing.T) {
 }
 
 func Test_Open_txLock(t *testing.T) {
-	db, err := sql.Open("sqlite3", filepath.Join(t.TempDir(), "test.db")+
+	db, err := sql.Open("sqlite3", "file:"+
+		filepath.Join(t.TempDir(), "test.db")+
 		"?_txlock=exclusive&_pragma=busy_timeout(0)")
 	if err != nil {
 		t.Fatal(err)
@@ -101,6 +102,10 @@ func Test_Open_txLock(t *testing.T) {
 	if rc := serr.Code(); rc != sqlite3.BUSY {
 		t.Errorf("got %d, want sqlite3.BUSY", rc)
 	}
+	var terr interface{ Temporary() bool }
+	if !errors.As(err, &terr) || !terr.Temporary() {
+		t.Error("not temporary", err)
+	}
 	if got := err.Error(); got != `sqlite3: database is locked` {
 		t.Error("got message: ", got)
 	}
@@ -111,6 +116,22 @@ func Test_Open_txLock(t *testing.T) {
 	}
 }
 
+func Test_Open_txLock_invalid(t *testing.T) {
+	db, err := sql.Open("sqlite3", "file::memory:?_txlock=xclusive")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	_, err = db.Conn(context.TODO())
+	if err == nil {
+		t.Fatal("want error")
+	}
+	if got := err.Error(); got != `sqlite3: invalid _txlock: xclusive` {
+		t.Error("got message: ", got)
+	}
+}
+
 func Test_BeginTx(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -122,7 +143,7 @@ func Test_BeginTx(t *testing.T) {
 	defer db.Close()
 
 	_, err = db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted})
-	if err != isolationErr {
+	if err.Error() != string(isolationErr) {
 		t.Error("want isolationErr")
 	}
 
@@ -205,7 +226,7 @@ func Test_Prepare(t *testing.T) {
 	}
 
 	_, err = db.Prepare(`SELECT 1; SELECT 2`)
-	if err != tailErr {
+	if err.Error() != string(tailErr) {
 		t.Error("want tailErr")
 	}
 }
diff --git a/error.go b/error.go
index 686c71e..fb4eb1d 100644
--- a/error.go
+++ b/error.go
@@ -50,6 +50,11 @@ func (e *Error) Error() string {
 	return b.String()
 }
 
+// Temporary returns true for [BUSY] errors.
+func (e *Error) Temporary() bool {
+	return e.Code() == BUSY
+}
+
 // SQL returns the SQL starting at the token that triggered a syntax error.
 func (e *Error) SQL() string {
 	return e.sql
@@ -60,6 +65,7 @@ type errorString string
 func (e errorString) Error() string { return string(e) }
 
 const (
+	binaryErr   = errorString("sqlite3: no SQLite binary embed/set/loaded")
 	nilErr      = errorString("sqlite3: invalid memory address or null pointer dereference")
 	oomErr      = errorString("sqlite3: out of memory")
 	rangeErr    = errorString("sqlite3: index out of range")
diff --git a/tests/compile/nil/compile_test.go b/tests/compile/nil/compile_test.go
new file mode 100644
index 0000000..5e3a8cc
--- /dev/null
+++ b/tests/compile/nil/compile_test.go
@@ -0,0 +1,14 @@
+package compile_empty
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+func TestCompile_empty(t *testing.T) {
+	_, err := sqlite3.Open(":memory:")
+	if err == nil {
+		t.Error("want error")
+	}
+}