以下代码中的 LINQ 是什么?

What is LINQ in following code?

 // GET: racunTest/Edit/5
    public ActionResult Edit(int? id)
    {
        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        racun racun = db.racuns.Find(id);
        if (racun == null)
        {
            return HttpNotFound();
        }
        ViewBag.kupac_id = new SelectList(db.kupacs, "id_kupac", "naziv", racun.kupac_id);
        return View(racun);
    }

    // POST: racunTest/Edit/5
    // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
    // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Edit([Bind(Include = "id_racun,dv_racuna,status,dv_placanja,kupac_id")] racun racun)
    {
        if (ModelState.IsValid)
        {
            db.Entry(racun).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        ViewBag.kupac_id = new SelectList(db.kupacs, "id_kupac", "naziv", racun.kupac_id);
        return View(racun);
    }

    // GET: racunTest/Delete/5
    public ActionResult Delete(int? id)
    {
        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        racun racun = db.racuns.Find(id);
        if (racun == null)
        {
            return HttpNotFound();
        }
        return View(racun);
    }

    // POST: racunTest/Delete/5
    [HttpPost, ActionName("Delete")]
    [ValidateAntiForgeryToken]
    public ActionResult DeleteConfirmed(int id)
    {
        racun racun = db.racuns.Find(id);
        db.racuns.Remove(racun);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

这段代码中有 LINQ 吗?它是什么,或者都是 LINQ。我必须使用 LINQ 从 DB 获取简单数据,但它看起来很难,我什至不知道我应该把 LINQ 代码放在哪里,以及如何显示数据? LINQ 和 LINQ to SQL 是一回事吗?

你的问题表明完全没有努力调查此事。

LINQ = 语言集成查询;它的语言结构允许您以类似于 SQL 的方式查询对象/数据库/其他。

首先阅读一些指南,例如 this