Nearly finished relationship bind helper

* If only reflection would be nice

boil/qm/query_mods.go

@@ -19,17 +19,14 @@ func SQL(sql string, args ...interface{}) QueryMod {
 	}
 }
 
-// Limit the number of returned rows
-func Limit(limit int) QueryMod {
+// Load allows you to specify foreign key relationships to eager load
+// for your query. Passed in relationships need to be in the format
+// MyThing or MyThings.
+// Relationship name plurality is important, if your relationship is
+// singular, you need to specify the singular form and vice versa.
+func Load(relationships ...string) QueryMod {
 	return func(q *boil.Query) {
-		boil.SetLimit(q, limit)
-	}
-}
-
-// Offset into the results
-func Offset(offset int) QueryMod {
-	return func(q *boil.Query) {
-		boil.SetOffset(q, offset)
+		boil.SetLoad(q, relationships...)
 	}
 }
 
@@ -99,6 +96,20 @@ func From(from string) QueryMod {
 	}
 }
 
+// Limit the number of returned rows
+func Limit(limit int) QueryMod {
+	return func(q *boil.Query) {
+		boil.SetLimit(q, limit)
+	}
+}
+
+// Offset into the results
+func Offset(offset int) QueryMod {
+	return func(q *boil.Query) {
+		boil.SetOffset(q, offset)
+	}
+}
+
 // Count turns the query into a counting calculation
 func Count() QueryMod {
 	return func(q *boil.Query) {

boil/query.go

@@ -20,6 +20,7 @@ const (
 type Query struct {
 	executor    Executor
 	plainSQL    plainSQL
+	load        []string
 	delete      bool
 	update      map[string]interface{}
 	selectCols  []string
@@ -101,6 +102,11 @@ func SetSQL(q *Query, sql string, args ...interface{}) {
 	q.plainSQL = plainSQL{sql: sql, args: args}
 }
 
+// SetLoad on the query.
+func SetLoad(q *Query, relationships ...string) {
+	q.load = append([]string(nil), relationships...)
+}
+
 // SetCount on the query.
 func SetCount(q *Query) {
 	q.modFunction = "COUNT"

boil/query_test.go

@@ -45,6 +45,21 @@ func TestSetSQL(t *testing.T) {
 	}
 }
 
+func TestSetLoad(t *testing.T) {
+	t.Parallel()
+
+	q := &Query{}
+	SetLoad(q, "one", "two")
+
+	if len(q.load) != 2 {
+		t.Errorf("Expected len 2, got %d", len(q.load))
+	}
+
+	if q.load[0] != "one" || q.load[1] != "two" {
+		t.Errorf("Was not expected string, got %s", q.load)
+	}
+}
+
 func TestWhere(t *testing.T) {
 	t.Parallel()
 

boil/reflect.go

@@ -6,6 +6,7 @@ import (
 	"reflect"
 	"strings"
 
+	"github.com/davecgh/go-spew/spew"
 	"github.com/pkg/errors"
 	"github.com/vattle/sqlboiler/strmangle"
 )
@@ -29,7 +30,8 @@ func (q *Query) BindP(obj interface{}) {
 // Bind rules:
 // - Struct tags control bind, in the form of: `boil:"name,bind"`
 // - If the "name" part of the struct tag is specified, that will be used
-// for binding instead of the snake_cased field name.
+// - f the "name" part of the tag is specified, it is used for binding
+// (the columns returned are title cased and matched).
 // - If the ",bind" option is specified on an struct field, it will be recursed
 // into to look for fields for binding.
 // - If the name of the struct tag is "-", this field will not be bound to
@@ -75,7 +77,55 @@ func (q *Query) Bind(obj interface{}) error {
 	}
 	defer rows.Close()
 
-	return bind(rows, obj, structType, sliceType, singular)
+	if res := bind(rows, obj, structType, sliceType, singular); res != nil {
+		return res
+	}
+
+	if len(q.load) == 0 {
+		return nil
+	}
+
+	return q.loadRelationships(obj, singular)
+}
+
+// loadRelationships calls the template generated eager load functions
+// (LoadTableName()) using reflection, to eager load the relationships
+// into the users Relationships struct attached to their object.
+func (q *Query) loadRelationships(obj interface{}, singular bool) error {
+	typ := reflect.TypeOf(obj).Elem().Elem()
+	if !singular {
+		typ = typ.Elem()
+	}
+
+	rel, found := typ.FieldByName("Relationships")
+	// If the users object has no Relationships struct, it must be
+	// a custom object and we should not attempt to load any relationships.
+	if !found {
+		return nil
+	}
+
+	for _, relationship := range q.load {
+		// Attempt to find the LoadRelationshipName function
+		loadMethod, found := rel.Type.MethodByName("Load" + relationship)
+		if !found {
+			return errors.Errorf("could not find Load%s method for eager loading", relationship)
+		}
+		spew.Dump(reflect.New(rel.Type).Interface().(**testRelationshipsStruct))
+		spew.Dump(reflect.Indirect(reflect.New(rel.Type)).Interface().(*testRelationshipsStruct))
+		methodArgs := []reflect.Value{
+			reflect.New(rel.Type),
+			reflect.ValueOf(q.executor),
+			reflect.ValueOf(singular),
+			reflect.ValueOf(obj),
+		}
+
+		resp := loadMethod.Func.Call(methodArgs)
+		if resp[0].Interface() != nil {
+			return resp[0].Interface().(error)
+		}
+	}
+
+	return nil
 }
 
 // bindChecks resolves information about the bind target, and errors if it's not an object

boil/reflect_test.go

@@ -103,6 +103,55 @@ func TestBindSingular(t *testing.T) {
 	}
 }
 
+var loadFunctionCalled bool
+
+type testRelationshipsStruct struct{}
+
+func (r *testRelationshipsStruct) LoadTestOne(exec Executor, singular bool, obj interface{}) error {
+	loadFunctionCalled = true
+	return nil
+}
+
+func TestLoadRelationships(t *testing.T) {
+	t.Parallel()
+
+	testSingular := []*struct {
+		ID            int
+		Relationships *testRelationshipsStruct
+	}{}
+
+	testSlice := []*struct {
+		ID            int
+		Relationships *testRelationshipsStruct
+	}{}
+
+	exec, _, err := sqlmock.New()
+	if err != nil {
+		t.Error(err)
+	}
+
+	q := Query{
+		load:     []string{"TestOne"},
+		executor: exec,
+	}
+
+	if err := q.loadRelationships(testSlice, true); err != nil {
+		t.Error(err)
+	}
+
+	if loadFunctionCalled == false {
+		t.Errorf("Load function was not called for testSlice")
+	}
+
+	if err := q.loadRelationships(testSingular, false); err != nil {
+		t.Error(err)
+	}
+
+	if loadFunctionCalled == false {
+		t.Errorf("Load function was not called for testSlice")
+	}
+}
+
 func TestBind_InnerJoin(t *testing.T) {
 	t.Parallel()