查询数据库中是否有某数据表存在的一种处理方式

今天做小项目的时候，遇到这么一个问题

 

于是思路就是说，用count(*) 来查询数据库中是否有这个表，我用到如下代码

 

 

 private void button6_Click(object sender, EventArgs e)
        {
            SqlConnection sqlCon1 = new SqlConnection("Data Source=BTAP-SHOW;Initial Catalog=myluoyi;Integrated Security=True");
            sqlCon1.Open();
            SqlCommand cmdtext = new SqlCommand("select count(*) from information_schema.tables where TABLE_NAME='T_union" + str +"'", sqlCon1);
            int Value = (int)cmdtext.ExecuteScalar();
          //  label1.Text = "有" + Value.ToString() + "条记录";
            sqlCon1.Close();

            if (Value == 0)
            {
                if (MessageBox.Show("数据还未处理过,是否现在处理?", "确认", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
                {
                    SqlCommand cmd1 = new SqlCommand("select distinct A.LinkID,A.Speed,B.Length,A.Len,A.Time,A.sampleNum,B.Class into T_union"+ str +" from T_youdutwo B inner join T_yongdu A on A.LinkID=B.LinkID", sqlCon1);
                    DataTable dt = new DataTable("T_youduthree123");
                    SqlDataAdapter dAd = new SqlDataAdapter(cmd1);
                    dAd.Fill(dt);
                    sqlCon1.Close();
                    MessageBox.Show("数据处理完毕！");
                    button6.Enabled = false;
                    button7.Enabled = true;
                    button8.Enabled = true;
                    button9.Enabled = true;
                }
            }
            else
            {
                MessageBox.Show("数据已经处理过了,您可以直接查询对应道路等级信息了!","提示",MessageBoxButtons.OK,MessageBoxIcon.Exclamation);
                button6.Enabled = false;
                button7.Enabled = true;
                button8.Enabled = true;
                button9.Enabled = true;
            }

            
                for (int j = 0; j < 2500000; j++) { }
                if (p.Value != p.Maximum)
                {
                    p.PerformStep();//按照 Step 属性中指定的数量增加进度栏的值
                    int l_value = 100 * (p.Value - p.Minimum) / (p.Maximum - p.Minimum);
                }
             
        }

 

 

 

注意问题的关键就在于下面这句：

 

 

select count(*) from information_schema.tables where TABLE_NAME=‘需要的表名字’