using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;

namespace WebSqlHelper
{
    public class SqlDbHelper : DbHelper
    {
        public SqlDbHelper(string name)
        {
            db = CreateDatabase(name);
        }
        public SqlDbHelper()
        {
            db = CreateDatabase();
        }
        public override DbParameter GetParameter()
        {
            return new SqlParameter();
        }
        public override DataTable ExecutePager(string tbname, string fields, string where, string orderby, int pagesize, int pageindex, ref int recordcount)
        {
            if (string.IsNullOrEmpty(fields))
            {
                fields = "*";
            }
            DbCommand storedProcCommand = db.GetStoredProcCommand("commonPager");
            storedProcCommand.Parameters.Clear();
            db.AddInParameter(storedProcCommand, "tblname", DbType.String, tbname);
            db.AddInParameter(storedProcCommand, "strGetFields", DbType.String, fields);
            db.AddInParameter(storedProcCommand, "PageSize", DbType.Int16, pagesize);
            db.AddInParameter(storedProcCommand, "PageIndex", DbType.Int16, pageindex);
            db.AddInParameter(storedProcCommand, "docount", DbType.Int16, 1);
            db.AddInParameter(storedProcCommand, "strOrderBy", DbType.String, orderby);
            db.AddInParameter(storedProcCommand, "strWhere", DbType.String, where);
            db.AddOutParameter(storedProcCommand, "RecordCount", DbType.Int32, 4);
            DataSet set = db.ExecuteDataSet(storedProcCommand);
            recordcount = (int)db.GetParameterValue(storedProcCommand, "RecordCount");
            return set.Tables[0];
        }
        public override int GetNext(string table, string field)
        {
            return GetNext(null, table, field);
        }
        public override int GetNext(DbTransaction tran, string table, string field)
        {
            object c = GetSqlStrScalar("select max(case when ISNUMERIC(" + field + ")=1 then " + field + " else 0 end) from " + table);
            if (c == null || c is DBNull)
                return 1;
            return int.Parse(c.ToString()) + 1;
        }
    }
}