Back to int64 because driver.Value doesn't support unsigned types.

README.md

@@ -23,7 +23,7 @@ Consider the following struct:
 
 ```
 type User struct {
-    Id       uint64  `json:"id"`
+    Id       int64  `json:"id"`
     Username string `json:"username"`
 }
 ```
@@ -46,7 +46,7 @@ type User struct {
 }
 ```
 
-Notice that the `uint64` ID got replaced by the `hide.ID`, which internally is represented as an `uint64` as well, but implements the marshal interface.
+Notice that the `int64` ID got replaced by the `hide.ID`, which internally is represented as an `int64` as well, but implements the marshal interface.
 This allows you to cast between them and use `hide.ID` as a replacement. The resulting JSON changes to the following:
 
 ```

id.go

@@ -7,10 +7,10 @@ import (
 	"strings"
 )
 
-// ID type that can be used as an replacement for uint64.
+// ID type that can be used as an replacement for int64.
 // It is converted to/from a hash value when marshalled to/from JSON.
 // Value 0 is considered null.
-type ID uint64
+type ID int64
 
 // Scan implements the Scanner interface.
 func (hide *ID) Scan(value interface{}) error {
@@ -19,7 +19,7 @@ func (hide *ID) Scan(value interface{}) error {
 		return nil
 	}
 
-	id, ok := value.(uint64)
+	id, ok := value.(int64)
 
 	if !ok {
 		return errors.New("unexpected type")
@@ -35,7 +35,7 @@ func (hide ID) Value() (driver.Value, error) {
 		return nil, nil
 	}
 
-	return uint64(hide), nil
+	return int64(hide), nil
 }
 
 // MarshalJSON implements the encoding json interface.

id_test.go

@@ -90,7 +90,7 @@ func TestUnmarshalIDStruct(t *testing.T) {
 
 func TestScan(t *testing.T) {
 	var id ID
-	value := uint64(123)
+	value := int64(123)
 
 	if err := id.Scan(value); err != nil {
 		t.Fatal(err)
@@ -109,10 +109,10 @@ func TestValue(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	_, ok := driverValue.(uint64)
+	_, ok := driverValue.(int64)
 
 	if !ok {
-		t.Fatal("Driver value must be of type uint64")
+		t.Fatal("Driver value must be of type int64")
 	}
 }