如何在创建表之前判断此表在数据库中是否存在？急求！！

Question

if exists(select * from sysobjects where name ='表名')

Answer 1

IF OBJECT_ID (N'bas_CardType') IS NULL
BEGIN  --如果不存在该表，则进行创建
    --drop table com_CodeRecord
    CREATE TABLE bas_CardType
(
FKey           UNIQUEIDENTIFIER 
                    --创建默认值
CONSTRAINT DF_bas_CardType_FKey DEFAULT (newid()) 
NOT NULL,  --不允许为空
        FCode          NVARCHAR(20),
FName        NVARCHAR(20)
CONSTRAINT PK_bas_CardType PRIMARY KEY (FKey)  --主键
)
   PRINT 'bas_CardType created'
END

Answer 2

我把我的代码发给你看下，版主！ private void CreatandInsert() 
        {
            string connectionString = "data source=QT-201309102116\\SQLEXPRESS;uid=sa;pwd=123456;database=gongan_183";
            ArrayList al = new ArrayList(); 
            foreach (DataTable dt in dataSet.Tables) 
            {
                string sql_creat = "Create Table " + Table_Name + " ( "; 
                foreach( DataColumn dc in dt.Columns )
                {
                    //MessageBox.Show(dc.ColumnName);//列名
                    sql_creat = sql_creat + dc.ColumnName.Replace(" ", "") +" ";
                    string datatype_test = dc.DataType.ToString();
                    string sql_datatype;
                    if (datatype_test == "System.Decimal")
                    {
                        sql_datatype = "decimal";
                        sql_creat += sql_datatype + ", ";
                    }
                    if (datatype_test == "System.String") 
                    {
                        //string dcname = dc.ColumnName.ToString();
                        //int len = dcname.Length;
                        sql_datatype = "varchar(240)";
                        sql_creat += sql_datatype + ", ";
                    }
                    if (datatype_test == "System.Boolean") 
                    {
                        sql_datatype="bit";
                        sql_creat += sql_datatype + ", ";
                    }
                    if (datatype_test == "System.DateTime") 
                    {
                        sql_datatype = "datetime";
                        sql_creat += sql_datatype + ", ";
                    }
                    if (datatype_test == "System.Int") 
                    {
                        sql_datatype = "int";
                        sql_creat += sql_datatype + ", ";
                    }                }
                sql_creat = sql_creat.Substring(0, sql_creat.Length - 2) + ") ";
                al.Add(sql_creat);
                try
                {
                    SqlConnection con = new SqlConnection(connectionString);
                    SqlCommand cmd1 = new SqlCommand(sql_creat, con);
                    con.Open();
                    cmd1.ExecuteNonQuery();
                    con.Close();
                }
                catch (Exception ex) 
                {
                    Console.WriteLine(ex.Message);
                }
                int a = 0;
                dataChanged(a);
                foreach(DataRow dr in dt.Rows)
                {
                    
                    string sql_insert = "insert into " + Table_Name + " ( ";
                    foreach (DataColumn dc in dt.Columns) 
                    {
                        sql_insert = sql_insert + dc.ColumnName.Replace(" ", "") + ",";
                    }
                    sql_insert = sql_insert.Substring(0, sql_insert.Length - 1) + ")";
                    sql_insert += " values (";
                    i = 0;
                    foreach (DataColumn dc in dt.Columns) 
                    {
                        string s = dr.ItemArray[i].ToString().Trim();
                        if (s == "")
                        {
                            sql_insert = sql_insert + "' ',";
                        }
                        else
                        {
                            sql_insert = sql_insert + "'"+dr.ItemArray[i].ToString().Trim() + "',";
                        }
                        i++;
                    } 
                    sql_insert = sql_insert.Substring(0, sql_insert.Length - 1) + ")";
                    al.Add(sql_insert);
                    try
                    {
                        SqlConnection con = new SqlConnection(connectionString);
                        SqlCommand cmd2 = new SqlCommand(sql_insert, con);
                        con.Open();
                        cmd2.ExecuteNonQuery();
                        con.Close();
                    }
                    catch(Exception ex) 
                    {
                        Console.WriteLine(ex.Message);
                    }
                    a++;
                    dataChanged((a*100)/dt.Rows.Count);
                }                dataChanged(100);
                MessageBox.Show("导入成功！！");
            }
        }

Answer 3

string sql_creat = "Create Table " + Table_Name + " ( "; 
这一语句改成
string sql_creat = "if not exists(select * from sysobjects where name ='"+Table_Name+"')  Create Table " + Table_Name + " ( "; 

Answer 4

貌似不行啊！
if exists这句是sql代码的你要用cmd执行

Answer 5

SELECT     COUNT(*) AS Expr1
FROM         sysobjects
WHERE  name ='"+Table_Name+"'
返回１就存在

Answer 6

http://bbs.csdn.net/topics/390585105
不久前有人发的帖子

Answer 7

 SqlConnection con = new SqlConnection("Data Source=10.168.1.5;Initial Catalog=data;User ID=sa;password=sa;Integrated Security=False");  
         con.Open();  
　　　　　string sql="SELECT COUNT(*) FROM sysobjects WHERE  name ='"+Table_Name+"'";
         SqlCommand cmd = new SqlCommand(sql, con);  
         if ((int)cmd.ExecuteScalar() > 0)  
         {  
             listBox1.Items.Add(s1 + " 表已经存在");  
         }           cmd.Dispose();  
         con.Close();  

Answer 8

messagebox.show("表已经存在!");