根据表名获取表字段信息
实际应用中不免需要调取数据库表字段的相关信息，特此将代码贴出，以作备用，调取的信息： 字段名、字段类型、字段长度、是否主键、说明
///
/// 创建SqlParameter
///
public class CP
{
public class ColumnInfo
{
public string ColName { get; set; }
public SqlDbType ColType { get; set; }
public int ColLength { get; set; }
public bool IsPrimary { get; set; }
public string Description { get; set; }
}
/// 指定表名，如果为空，则查询所有表
/// 数据库连接串
/// TC(string specifyTable, string connStr)
{
List p = new List();
using (SqlConnection conn = new SqlConnection(connStr))
{
StringBuilder sb = new StringBuilder(1000);
sb.Append("SELECT a.name,(case when (SELECT count(*) FROM sysobjects WHERE (name in (SELECT name FROM sysindexes WHERE (id = a.id) AND (indid in (SELECT indid FROM sysindexkeys WHERE (id = a.id) AND (colid in (SELECT colid FROM syscolumns WHERE (id = a.id) AND (name = a.name))))))) AND (xtype = 'PK'))>0 then '1' else '0' end) isprimary,b.name [type],COLUMNPROPERTY(a.id,a.name,'PRECISION') as [length],isnull(g.value,'') as [description] FROM syscolumns a ");
sb.Append("left join systypes b on a.xtype=b.xusertype inner join sysobjects d on a.id=d.id and d.xtype='U' and d.name<>'dtproperties'");
sb.Append("left join syscomments e on a.cdefault=e.id left join sys.extended_properties g on a.id=g.major_id AND a.colid = g.minor_id where d.name =@tname order by a.id,a.colorder");
conn.Open();
SqlCommand cmd = new SqlCommand(sb.ToString(), conn);
cmd.Parameters.Add(new SqlParameter("@tname", SqlDbType.VarChar, 30));
cmd.Parameters[0].Value = specifyTable;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
sda.Fill(ds);
DataTable dt = ds.Tables[0];
int count = dt.Rows.Count;
if (count > 0)
{
for (int i = 0; i < count; i++)
{
ColumnInfo item = new ColumnInfo() { ColName = dt.Rows[i]["name"].ToString(), ColLength = int.Parse(dt.Rows[i]["length"].ToString()), ColType = StringToSqlType(dt.Rows[i]["type"].ToString()), IsPrimary = (dt.Rows[i]["isprimary"].ToString() == "1" ? true : false), Description = dt.Rows[i]["description"].ToString() };
p.Add(item);
}
}
}
return p;
}
}
//SqlServer数据库类型转换方法
public static SqlDbType StringToSqlType(string String)
{
SqlDbType dbType = SqlDbType.Variant;//默认为Object
switch (String)
{
case "int":
dbType = SqlDbType.Int;
break;
case "varchar":
dbType = SqlDbType.VarChar;
break;
case "bit":
dbType = SqlDbType.Bit;
break;
case "datetime":
dbType = SqlDbType.DateTime;
break;
case "decimal":
dbType = SqlDbType.Decimal;
break;
case "float":
dbType = SqlDbType.Float;
break;
case "image":
dbType = SqlDbType.Image;
break;
case "money":
dbType = SqlDbType.Money;
break;
case "ntext":
dbType = SqlDbType.NText;
break;
case "nvarchar":
dbType = SqlDbType.NVarChar;
break;
case "smalldatetime":
dbType = SqlDbType.SmallDateTime;
break;
case "smallint":
dbType = SqlDbType.SmallInt;
break;
case "text":
dbType = SqlDbType.Text;
break;
case "bigint":
dbType = SqlDbType.BigInt;
break;
case "binary":
dbType = SqlDbType.Binary;
break;
case "char":
dbType = SqlDbType.Char;
break;
case "nchar":
dbType = SqlDbType.NChar;
break;
case "numeric":
dbType = SqlDbType.Decimal;
break;
case "real":
dbType = SqlDbType.Real;
break;
case "smallmoney":
dbType = SqlDbType.SmallMoney;
break;
case "sql_variant":
dbType = SqlDbType.Variant;
break;
case "timestamp":
dbType = SqlDbType.Timestamp;
break;
case "tinyint":
dbType = SqlDbType.TinyInt;
break;
case "uniqueidentifier":
dbType = SqlDbType.UniqueIdentifier;
break;
case "varbinary":
dbType = SqlDbType.VarBinary;
break;
case "xml":
dbType = SqlDbType.Xml;
break;
}
return dbType;
}
#region 建立一个参数
///
/// 根据表列信息集合和表对应实体类所属某个属性返回一个SQL参数
///
/// 表列信息集合
/// 属性
/// 属性对应值
/// 参数方向
/// 一个SQL参数，已经初始化
public static SqlParameter cPa(ColumnInfo item, object v, ParameterDirection pd)
{
if (item == null)
{
return null;
}
SqlParameter sp = null;
if (item != null)
{
sp = new SqlParameter("@" + item.ColName, item.ColType, item.ColLength);
sp.Direction = pd;
sp.Value = v;
}
return sp;
}
///
/// 根据表列信息集合和表对应实体类所属某个属性返回一个SQL参数
///
/// 表列信息集合
/// 属性
/// 属性对应值
/// 一个SQL参数，已经初始化
public static SqlParameter cPa(ColumnInfo item, object v)
{
if (item == null)
{
return null;
}
SqlParameter sp = null;
if (item != null)
{
sp = new SqlParameter("@" + item.ColName, item.ColType, item.ColLength);
sp.Direction = ParameterDirection.Input;
sp.Value = v;
}
return sp;
}
#endregion
}