func (maker *courseMaker) GetByID(id int64) (*Course, error) {
var (
err error
get_course string = queries["get_course"]
get_course_members string = queries["get_course_members"]
get_course_teachers string = queries["get_course_teachers"]
course *Course = NewCourse()
studentIDs []int64 = []int64{}
teacherIDs []int64 = []int64{}
stmt *sqlx.Stmt
acid util.AcidTx
)
// Get the course's name.
acid = func(tx *sqlx.Tx) {
// Add the course
stmt, err = tx.Preparex(get_course)
PanicOnError(err)
err = stmt.Get(course, id)
PanicOnError(err)
// Get the rows out of course_members
stmt, err = tx.Preparex(get_course_members)
PanicOnError(err)
err = stmt.Select(&studentIDs, id)
PanicOnError(err)
// Get the rows out of course_teachers
stmt, err = tx.Preparex(get_course_teachers)
PanicOnError(err)
stmt.Select(&teacherIDs, id)
PanicOnError(err)
for _, studentID := range studentIDs {
student, err := StudentStore.GetByID(studentID)
PanicOnError(err)
course.Students = append(course.Students, student)
}
for _, teacherID := range teacherIDs {
teacher, err := TeacherStore.GetByID(teacherID)
PanicOnError(err)
course.Teachers = append(course.Teachers, teacher)
}
}
err = util.AcidCtx(acid, maker)
if err != nil {
return nil, err
}
return course, nil
}
func (maker *courseMaker) Create(course *Course) error {
var (
err error
courseQuery = queries["create_course"]
courseMemberQuery = queries["create_course_members"]
courseTeachersQuery = queries["create_course_teachers"]
acid util.AcidTx
result sql.Result
stmt *sqlx.Stmt
)
acid = func(tx *sqlx.Tx) {
// Add the course
stmt, err = tx.Preparex(courseQuery)
if err != nil {
panic(err)
}
if result, err = stmt.Exec(course.Name); err != nil {
panic(err)
}
course.ID, err = result.LastInsertId()
if err != nil {
panic(err)
}
// Then add a new record for each of the students to course_members
for _, student := range course.Students {
stmt, err = tx.Preparex(courseMemberQuery)
if err != nil {
panic(err)
}
if result, err = stmt.Exec(course.ID, student.ID); err != nil {
panic(err)
}
}
// Then add a new record for each of the teachers to course_teachers
for _, teacher := range course.Teachers {
stmt, err = tx.Preparex(courseTeachersQuery)
if err != nil {
panic(err)
}
if result, err = stmt.Exec(course.ID, teacher.ID); err != nil {
panic(err)
}
}
}
return util.AcidCtx(acid, maker)
}