少量數據時操作快,不需外部依賴,如sqlite雖然也很好用,但需要不少外部的dll
性能:
初始化代碼:
dt = new DataTable("t"); dt.Columns.Add("id"); dt.Columns.Add("msg"); int i = 0; for (; i < 1000000; i++) { dt.Rows.Add(i, Guid.NewGuid().ToString()); dic[i.ToString()] = i.ToString(); } this.textBox1.Text = Guid.NewGuid().ToString(); dt.Rows.Add(i, this.textBox1.Text); dt.PrimaryKey = new DataColumn[] { dt.Columns["ID"] };
普通查詢,100萬行,首次查詢需5000ms,後續查詢都在1ms內,按列msg查詢也一樣,缺點是第1次很慢:
Stopwatch sw = Stopwatch.StartNew(); DataRow[] drs = dt.Select("id = '600000'"); this.textBox2.Text = drs.Length.ToString(); this.textBox3.Text = sw.Elapsed.TotalMilliseconds.ToString(); sw.Stop();
按字典查詢,首次和後續都在1ms內,我以前都這樣做,實際上按主鍵查詢即可,這個額外維護了一個字典。
Stopwatch sw = Stopwatch.StartNew(); this.textBox2.Text = dic["60000"]; this.textBox3.Text = sw.Elapsed.TotalMilliseconds.ToString(); sw.Stop();
按主鍵查詢,首次和後續都在1ms內,未找到時返回null。必須要有主鍵,可以是複合主鍵
Stopwatch sw = Stopwatch.StartNew(); object[] objs = new object[] { "60000000" }; DataRow dr = dt.Rows.Find(objs); this.textBox2.Text = dr[0].ToString(); this.textBox3.Text = sw.Elapsed.TotalMilliseconds.ToString(); sw.Stop();