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  • DbHelperSQL 判断数据库表结构公用方法

    #region 公用方法
            /// <summary>
            /// 判断是否存在某表的某个字段
            /// </summary>
            /// <param name="tableName">表名称</param>
            /// <param name="columnName">列名称</param>
            /// <returns>是否存在</returns>
            public static bool ColumnExists(string tableName, string columnName)
            {
                string sql = "select count(1) from syscolumns where [id]=object_id('" + tableName + "') and [name]='" + columnName + "'";
                object res = GetSingle(sql);
                if (res == null)
                {
                    return false;
                }
                return Convert.ToInt32(res) > 0;
            }
            public static int GetMinID(string FieldName, string TableName)
            {
                string strsql = "select min(" + FieldName + ") from " + TableName;
                object obj = DbHelperSQL.GetSingle(strsql);
                if (obj == null)
                {
                    return 0;
                }
                else
                {
                    return int.Parse(obj.ToString());
                }
            }
            public static int GetMaxID(string FieldName, string TableName)
            {
                string strsql = "select max(" + FieldName + ")+1 from " + TableName;
                object obj = DbHelperSQL.GetSingle(strsql);
                if (obj == null)
                {
                    return 1;
                }
                else
                {
                    return int.Parse(obj.ToString());
                }
            }
            public static bool Exists(string strSql)
            {
                object obj = DbHelperSQL.GetSingle(strSql);
                int cmdresult;
                if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                {
                    cmdresult = 0;
                }
                else
                {
                    cmdresult = int.Parse(obj.ToString());
                }
                if (cmdresult == 0)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
            /// <summary>
            /// 表是否存在
            /// </summary>
            /// <param name="TableName"></param>
            /// <returns></returns>
            public static bool TabExists(string TableName)
            {
                string strsql = "select count(*) from sysobjects where id = object_id(N'[" + TableName + "]') and OBJECTPROPERTY(id, N'IsUserTable') = 1";
                //string strsql = "SELECT count(*) FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[" + TableName + "]') AND type in (N'U')";
                object obj = DbHelperSQL.GetSingle(strsql);
                int cmdresult;
                if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                {
                    cmdresult = 0;
                }
                else
                {
                    cmdresult = int.Parse(obj.ToString());
                }
                if (cmdresult == 0)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
            public static bool Exists(string strSql, params SqlParameter[] cmdParms)
            {
                object obj = DbHelperSQL.GetSingle(strSql, cmdParms);
                int cmdresult;
                if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                {
                    cmdresult = 0;
                }
                else
                {
                    cmdresult = int.Parse(obj.ToString());
                }
                if (cmdresult == 0)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
            #endregion

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  • 原文地址:https://www.cnblogs.com/woanon/p/3261701.html
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