save ado pls. out of mem exception

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using System.IO;
using System.Drawing;

using EvilDICOM;

namespace ADOnet
{
    class Program
{

        static int check_tablename(string table, SqlConnection connection) {
            connection.Open();
            DataTable dTable = connection.GetSchema("TABLES", new string[] { null, null, table });

            if (dTable.Rows.Count > 0) {
                connection.Close();
                return 1;
            }
            Console.WriteLine("table does not exist");
            connection.Close();
            return -1;
        }


        static int check_colname(string colname, string table, SqlConnection connection)
        {
            connection.Open();
            DataTable dTable = connection.GetSchema("TABLES", new string[] { null, null, table });

            if (dTable.Rows.Count > 0) {

                string q = string.Format("select * from {0}", table);
                SqlCommand command = new SqlCommand(q, connection);
                SqlDataReader reader = command.ExecuteReader();
                if (reader.Read()) {

                    int fieldCount = reader.FieldCount;
                    string[] fields = new string[fieldCount];

                    for (int j = 0; j < fieldCount; j++) {
                        fields[j] = reader.GetName(j);
                    }

                    if (fields.Contains<String>(colname)) {
                        reader.Close();
                        connection.Close();
                        return 1;
                    }
                }
                reader.Close();
            }

            Console.WriteLine("column does not exist");
            connection.Close();
            return -1;
        }


        static int run(SqlCommand command, SqlConnection connection) {
            try {
                command.ExecuteNonQuery();

            } catch (SqlException e) {
                Console.WriteLine(e.Message);
                return -1;
            }
            return 0;
        }


        static void exec(SqlCommand command)
        {
            try
            {

                SqlDataReader reader = command.ExecuteReader();
                do
                {
                    while (reader.Read())
                    {
                        Object[] values = new Object[reader.FieldCount];
                        int fieldCount = reader.GetValues(values);

                        for (int i = 0; i < fieldCount; i++)
                        {
                            Console.Write("\t\t{0}", values[i]);
                        }
                        Console.WriteLine();
                    }

                } while (reader.NextResult());

                reader.Close();


            }
            catch (Exception e) { Console.WriteLine(e.Message); }

            Console.WriteLine();
        }

        static void PrintTable(DataTable dt) {
            DataTableReader dtReader = dt.CreateDataReader();

            while (dtReader.Read()) {
                for (int i = 0; i < dtReader.FieldCount; i++) {
                    Console.Write("\t{0}", dtReader.GetValue(i).ToString());
                }
                Console.WriteLine();
            }
            dtReader.Close();
        }



        //some new methods for CDB


        public static byte[] imageToByteArray(System.Drawing.Image imageIn)
        {
            MemoryStream ms = new MemoryStream();
            imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            return ms.ToArray();
        }

        public static Image byteArrayToImage(byte[] byteArrayIn)
        {
            MemoryStream ms = new MemoryStream(byteArrayIn);
            Image returnImage = Image.FromStream(ms);
            return returnImage;
        }





        static void flood(SqlCommand command, SqlConnection connection)
        {
            int i, j = 0, k, l, m, p;
            string[] tableNames = new string[20];

            try
            {
                SqlDataReader reader = command.ExecuteReader();
                do
                {
                    while (reader.Read())
                    {
                        Object[] values = new Object[reader.FieldCount];
                        int fieldCount = reader.GetValues(values);

                        for (i = 0; i < fieldCount; i++)
                        {
                            tableNames[j] = values[i].ToString();
                            j++;


                            Console.Write("\t\t{0}", values[i]);

                        }
                        Console.WriteLine();
                    }

                } while (reader.NextResult());

                reader.Close();


            }
            catch (Exception e) { Console.WriteLine(e.Message); }




            for (i = 0; i < j; i++)
            {
                //ArrayList colNames = new ArrayList();
                //ArrayList colTypes = new ArrayList();
                List<Tuple<string, string, int>> colNameToTypeToLen = new List<Tuple<string, string, int>>();


                String getColTypes = "SELECT COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH " +
                                    "FROM INFORMATION_SCHEMA.COLUMNS " +
                                    "WHERE TABLE_NAME = N'" + tableNames[i] + "'";

                SqlCommand getColTypesCmd = new SqlCommand(getColTypes, connection);
                SqlDataReader innerTypeReader = getColTypesCmd.ExecuteReader();

                do
                {
                    while (innerTypeReader.Read())
                    {
                        Object[] innerValues = new Object[innerTypeReader.FieldCount];
                        int innerFieldCount = innerTypeReader.GetValues(innerValues);

                        string colName = null;
                        string colType = null;
                        int colLen = 1;

                        colName = innerValues[0].ToString();
                        colType = innerValues[1].ToString();
                        colLen = !"".Equals(innerValues[2].ToString()) ?
                            Int32.Parse(innerValues[2].ToString()) : 3;

                        //Console.Write(" {0}_[{1}]_{2}", colName, colType, colLen);


                        colNameToTypeToLen.Add(new Tuple<string, string, int>(colName, colType, colLen));


                    }

                } while (innerTypeReader.NextResult());
                innerTypeReader.Close();


                int entryNum = 10;
                String valueForEntireTable = "\n\ninsert into " + tableNames[i] + "values ";

                for (p = 0; p < entryNum; p++)
                {
                    valueForEntireTable += " (";
                    foreach (var ntl in colNameToTypeToLen)
                    {
                        string name = ntl.Item1;
                        string type = ntl.Item2;
                        int len = ntl.Item3;


                        String randomShit = generateRandomEntry(type, len);
                        //Console.WriteLine(randomShit);


                        valueForEntireTable += randomShit + ", ";
                        //Console.WriteLine("Amount is {0} and type is {1}", money.amount, money.type);
                    }
                    valueForEntireTable = valueForEntireTable.Remove(valueForEntireTable.Length - 2);
                    valueForEntireTable += "), ";
                }
                valueForEntireTable = valueForEntireTable.Remove(valueForEntireTable.Length - 2);

                Console.WriteLine(valueForEntireTable);

                Console.WriteLine();
            }

            Console.WriteLine();
        }


        private static string generateRandomEntry(string type, int len)
        {
            int minLen = 2;
            int maxLen = len;
            //Random rng = new Random();

            int k = len;//rng.Next(minLen, maxLen) / 2;

            string randomBaseAlphabetNumbers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            string randomBaseAlphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ";
            string randomBaseNumbers = "0123456789";
            string retVal = "";

            if ("int".Equals(type))
                retVal = RandomString(k, randomBaseNumbers);

            if ("nvarchar".Equals(type))
            {
                retVal = "'" + RandomString(k / 3, randomBaseAlphabet) + "'";
            }

            if ("varchar".Equals(type))
            {
                retVal = "'" + RandomString(k / 3, randomBaseAlphabet) + "'";
            }

            if ("char".Equals(type))
            {
                retVal = "'" + RandomString(k, randomBaseAlphabet) + "'";
            }

            if ("nchar".Equals(type))
            {
                retVal = "'" + RandomString(k, randomBaseAlphabet) + "'";
            }

            if ("text".Equals(type))
            {
                retVal = "'" + RandomString(k / 3, randomBaseAlphabet) + "'";
            }

            if ("date".Equals(type))
            {
                string randDate = RandomDay().ToString();
                randDate = randDate.Remove(randDate.Length - 8);
                string[] tmp = randDate.Split('.');
                string newDate = tmp[2] + "-" + tmp[1] + "-" + tmp[0];

                retVal = "'" + newDate + "'";
            }
            if ("real".Equals(type))
                retVal = GetRandomDouble(3d, 5d).ToString();

            return retVal;
        }


        private static Random random = new Random();
        public static string RandomString(int length, string c)
        {
            string chars = c;
            return new string(Enumerable.Repeat(chars, length)
              .Select(s => s[random.Next(s.Length)]).ToArray());
        }

        private static Random gen = new Random();
        private static DateTime RandomDay()
        {
            DateTime start = new DateTime(1995, 10, 2);
            int range = (DateTime.Today - start).Days;
            return start.AddDays(gen.Next(range));
        }

        private static double GetRandomDouble(double minimum, double maximum)
        {
            Random random = new Random();
            return random.NextDouble() * (maximum - minimum) + minimum;
        }

//---------------------------------------------------------
//--------------------------MAIN---------------------------
//---------------------------------------------------------


        static void Main(string[] args)
        {
            try
            {
                /*
1. создаешь в sql студии бд с таблицами
2. создаешь app.config (или он по-умолчанию создастся) где пишиешь сервер и бд для подключения.
3. в проге создаешь экземпляр соединения через строку подключения.
4. как-нибудь обрабатываешь sql команды идущие на вход в виде: 1. открыл соединение, 2. создал SqlCommand(comm, conn) (если это ins/upd/del то добавляешь параметры через addwithValue или как еще), 3. выполнил ее (через DataReader или без него), закрыл соединение (это обязательно каждый раз откр-закр).
далее несвязанный уровень:
1. создал датасет, адаптер и билдер для него
2. обработал sql запрос так же, в таблицу из датасета (datatable) внес изменения (row.delete, row[x][y] = z, rows.add),
3. сделал отдельную команду которая вносит изменения в датасет (именно отдельная команда, чтоб ты "связывал" данные только когда сам захочешь).
4. вы восхитительны
*/




                SqlConnection connection;

                try {
                    string connectionString = ConfigurationManager.ConnectionStrings["AdoConnString"].ConnectionString;
                    connection = new SqlConnection(connectionString);
                    Console.WriteLine("conn has been set");
                }
                catch (Exception e) { Console.WriteLine(e.Message); Console.ReadLine(); return; }

                connection.Open();

                /*exec(new SqlCommand("SELECT COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH " +
                                    "FROM INFORMATION_SCHEMA.COLUMNS " +
                                    "WHERE TABLE_NAME = N'Person'", connection));*/

                flood(new SqlCommand("select TABLE_NAME from INFORMATION_SCHEMA.TABLES", connection), connection);

                Console.ReadLine();




                //here comes CDB
                /*
                Console.WriteLine("retrieving dicom");

                var theFile = new EvilDICOM.Core.IO.Reading.DICOMFileReader();

                //DicomFile("skull2.dcm");
                //theFile.Load();
                //byte[] thePixels = theFile.DataSet[DicomTags.PixelData].Values;



                Image img = Image.FromFile("tex_snoop.png");
                byte[] imgAsBytes = imageToByteArray(img);
                byte[] bytesAsImg;

                connection.Open();

                SqlCommand insCmd;
                insCmd = new SqlCommand("saveImage", connection);

                insCmd.CommandType = CommandType.StoredProcedure;
                insCmd.Parameters.Add("@img", SqlDbType.Image).Value = imgAsBytes;
                insCmd.Parameters.Add("@meta", SqlDbType.Text).Value = "some meta data";

                insCmd.ExecuteNonQuery();

                Console.WriteLine("image has been saved succesfully");
                Console.ReadLine();


                exec(new SqlCommand("select * from images", connection));


                SqlCommand readCmd = new SqlCommand("readImage", connection);

                readCmd.CommandType = CommandType.StoredProcedure;
                readCmd.Parameters.Add("@id", SqlDbType.Int).Value = 1;

                readCmd.ExecuteNonQuery();
                SqlDataAdapter adp = new SqlDataAdapter(readCmd);
                DataTable dTable = new DataTable();
                try
                {
                    adp.Fill(dTable);
                    if (dTable.Rows.Count > 0)
                    {
                        MemoryStream ms = new MemoryStream((byte[])dTable.Rows[0]["img_data"]);
                        bytesAsImg = imageToByteArray(Image.FromStream(ms));
                        Console.WriteLine("img has been retrieved");
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }

                String filename = "new_snoop";
                var fs = new BinaryWriter(new FileStream(@"C:\\tmp\\" + filename + ".png", FileMode.Append, FileAccess.Write));
                fs.Write(imgAsBytes);
                fs.Close();

                Console.ReadLine();
                */



                //back to ado lab

                Console.WriteLine("Connection has been opened.");
                Console.WriteLine("Cвязный уровень");
                Console.WriteLine("type 'help' for help");

                string com;

                while (true)
                {
                    string table, column, q;
                    Console.Write(">");
                    com = Console.ReadLine();

                    if (com.Equals(""))
                        continue;
//=========================================================
//------------------------SELECT---------------------------
//=========================================================
                    if ('s' == com[0])
                    {
                        Console.Write("->tables | * | column:");
                        string subcom = Console.ReadLine();

                        if (subcom.Equals(""))
                            continue;

                        if ('t' == subcom[0])
                        {
                            q = "select * from INFORMATION_SCHEMA.TABLES";
                            connection.Open();
                            SqlCommand cmd = new SqlCommand(q, connection);

                            exec(cmd);
                            connection.Close();
                        }

                        if ('*' == subcom[0])
                        {
                            Console.Write("->tablename:");
                            table = Console.ReadLine();
                            if (-1 == check_tablename(table, connection))
                                continue;

                            connection.Open();
                            q = string.Format("select * from {0}", table);
                            SqlCommand cmd = new SqlCommand(q, connection);

                            exec(cmd);
                            connection.Close();
                        }

                        if ('c' == subcom[0])
                        {
                            Console.Write("->tablename:");
                            table = Console.ReadLine();
                            if (-1 == check_tablename(table, connection))
                                continue;

                            Console.Write("-->column name:");
                            column = Console.ReadLine();
                            if (-1 == check_colname(column, table, connection))
                                continue;

                            connection.Open();
                            q = string.Format("select {0} from {1}", column, table);
                            SqlCommand cmd = new SqlCommand(q, connection);

                            exec(cmd);
                            connection.Close();
                        }

                        if (subcom.Equals("q"))
                            continue;
                    }


//=========================================================
//------------------------INSERT---------------------------
//=========================================================
                    if ('i' == com[0])
                    {
                        Console.Write("->tablename:");
                        table = Console.ReadLine();
                        if (-1 == check_tablename(table, connection))
                            continue;

                        connection.Open();
                        q = string.Format("select * from {0}", table);
                        SqlCommand command = new SqlCommand(q, connection);
                        SqlDataReader reader = command.ExecuteReader();

                        //get column names as result of simple <select*> query
                        if (reader.Read())
                        {

                            int fieldCount = reader.FieldCount;

                            //form query string
                            q = string.Format("insert into {0} (", table);
                            for (int j = 0; j < fieldCount; j++)
                            {
                                q += reader.GetName(j) + ", ";
                            }
                            q = q.Remove(q.Length - 2);
                            q += ") values (";
                            for (int j = 0; j < fieldCount; j++)
                            {
                                q += "@" + reader.GetName(j) + ", ";
                            }
                            q = q.Remove(q.Length - 2);
                            q += ")";
                            Console.WriteLine("Q:" + q);


                            SqlCommand cmd = new SqlCommand(q, connection);

                            //get parameters and add to command
                            for (int j = 0; j < fieldCount; j++) {
                                Console.Write("-->{0}[{1}]:", reader.GetName(j), reader.GetDataTypeName(j));
                                Object value = Console.ReadLine();

                                cmd.Parameters.AddWithValue("@" + reader.GetName(j), value);
                            }

                            reader.Close();

                            if (0 == run(cmd, connection))
                                Console.WriteLine("entry has been inserted");

                        } else {
                            reader.Close();
                        }
                        connection.Close();
                    }


//=========================================================
//------------------------DELETE---------------------------
//=========================================================
                    if ('d' == com[0])
                    {
                        Console.Write("->tablename:");
                        table = Console.ReadLine();
                        if (-1 == check_tablename(table, connection))
                            continue;

                        connection.Open();
                        q = string.Format("select * from {0}", table);
                        SqlCommand command = new SqlCommand(q, connection);
                        SqlDataReader reader = command.ExecuteReader();

                        if (reader.Read())
                        {

                            Object[] del_values = new Object[reader.FieldCount];//array of values to delete
                            int[] field_indices = new int[reader.FieldCount];//array of their indices in table
                            int delete_col_num = 0, fieldCount = reader.FieldCount;

                            q = string.Format("delete {0} where ", table);

                            for (int j = 0; j < fieldCount; j++)
                            {
                                Console.Write("-->del by {0}? Y/N:", reader.GetName(j));
                                string t_com = Console.ReadLine();

                                if ('n' == t_com[0] || 'N' == t_com[0]) {
                                    continue;
                                }
                                else {
                                    Console.Write("-->{0}[{1}] value:", reader.GetName(j), reader.GetDataTypeName(j));
                                    del_values[delete_col_num] = Console.ReadLine();

                                    field_indices[delete_col_num] = j;
                                    q += reader.GetName(j) + " = @" + reader.GetName(j) + " and ";
                                    delete_col_num++;
                                }
                            }

                            if (0 == delete_col_num)
                            {
                                Console.WriteLine("delete parameters are missing");
                                reader.Close();
                                connection.Close();
                                continue;
                            }
                            q = q.Remove(q.Length - 5);
                            Console.WriteLine("Q:" + q);



                            SqlCommand cmd = new SqlCommand(q, connection);

                            for (int k = 0; k < delete_col_num; k++) {
                                cmd.Parameters.AddWithValue("@" + reader.GetName(field_indices[k]), del_values[k]);
                            }
                            reader.Close();

                            if (0 == run(cmd, connection))
                                Console.WriteLine("entry(-ies) has been deleted");

                        } else {
                            reader.Close();
                        }
                        connection.Close();
                    }


//=========================================================
//------------------------UPDATE---------------------------
//=========================================================
                    if ('u' == com[0])
                    {
                        Console.Write("->tablename:");
                        table = Console.ReadLine();
                        if (-1 == check_tablename(table, connection))
                            continue;

                        connection.Open();
                        q = string.Format("select * from {0}", table);
                        SqlCommand command = new SqlCommand(q, connection);
                        SqlDataReader reader = command.ExecuteReader();

                        if (reader.Read())
                        {
                            Object[] old_values = new Object[reader.FieldCount];
                            int[] old_field_indices = new int[reader.FieldCount];//array of their indices in table
                            Object[] new_values = new Object[reader.FieldCount];
                            int[] new_field_indices = new int[reader.FieldCount];//array of their indices in table
                            int new_col_num = 0, old_col_num = 0, fieldCount = reader.FieldCount;

                            q = string.Format("update {0} set ", table);

                            for (int j = 0; j < fieldCount; j++) {
                                Console.Write("-->modify {0}? Y/N:", reader.GetName(j));
                                string t_com = Console.ReadLine();

                                if ('n' == t_com[0] || 'N' == t_com[0]) {
                                    continue;
                                }
                                else {
                                    Console.Write("-->{0}[{1}] value:", reader.GetName(j), reader.GetDataTypeName(j));
                                    new_values[new_col_num] = Console.ReadLine();
                                    new_field_indices[new_col_num] = j;
                                    q += reader.GetName(j) + " = @new" + reader.GetName(j) + ", ";
                                    new_col_num++;
                                }
                            }
                            q = q.Remove(q.Length - 2);

                            q += " where ";
                            for (int j = 0; j < fieldCount; j++) {
                                Console.Write("-->by {0}? Y/N:", reader.GetName(j));
                                string t_com = Console.ReadLine();

                                if ('n' == t_com[0] || 'N' == t_com[0]) {
                                    continue;
                                }
                                else {
                                    Console.Write("-->{0}[{1}] value:", reader.GetName(j), reader.GetDataTypeName(j));
                                    old_values[old_col_num] = Console.ReadLine();
                                    old_field_indices[old_col_num] = j;
                                    q += reader.GetName(j) + " = @old" + reader.GetName(j) + " and ";
                                    old_col_num++;
                                }
                            }
                            q = q.Remove(q.Length - 5);
                            Console.WriteLine("Q:" + q);

                            if (0 == new_col_num || 0 == old_col_num)
                            {
                                Console.WriteLine("delete or update parameters are missing");
                                reader.Close();
                                connection.Close();
                                continue;
                            }



                            SqlCommand cmd = new SqlCommand(q, connection);

                            for (int k = 0; k < new_col_num; k++) {
                                cmd.Parameters.AddWithValue("@new" + reader.GetName(new_field_indices[k]), new_values[k]);
                            }
                            for (int k = 0; k < old_col_num; k++) {
                                cmd.Parameters.AddWithValue("@old" + reader.GetName(old_field_indices[k]), old_values[k]);
                            }

                            reader.Close();

                            if (0 == run(cmd, connection))
                                Console.WriteLine("entry(-ies) has been updated");

                        } else {
                            reader.Close();
                        }
                        connection.Close();
                    }


//=========================================================
//------------------------EXPLICIT-------------------------
//=========================================================
                    if ('e' == com[0])
                    {
                        connection.Open();

                        Console.Write("->");
                        q = Console.ReadLine();
                        SqlCommand cmd = new SqlCommand(q, connection);

                        exec(cmd);

                        connection.Close();
                    }

                    if ('h' == com[0])
                    {
                        Console.WriteLine("Available commands:");
                        Console.Write("\tselect\n\t\ttables\n\t\t*\n\t\t\t<table_name>\n\t\tcolumn\n\t\t\t<table_name>\n\t\t\t\t<column_name>\n");
                        Console.Write("\tinsert\n\t\t<table_name>\n\t\t\t<value_string>\n");
                        Console.Write("\tdelete\n\t\t<table_name>\n\t\t\t<by-fields>\n");
                        Console.Write("\tupdate\n\t\t<table_name>\n\t\t\t<fields to modify>\n\t\t\t\t<by-fields>\n");
                        Console.WriteLine("\texplicit\n\t\t<explicit_query>\n");
                        Console.WriteLine("\tПерейти на Несвязный уроень / Выйти = [q]");
                    }

                    if (com.Equals("q"))
                        break;

                }

                Console.Write("Выйти = [q]\nПерейти на Несвзный уровень = [Any_key]\nПерейти?:");
                com = Console.ReadLine();

                if (com.Equals("q") && !com.Equals(""))
                {
                    Console.WriteLine("Closing connection. App will shut down soon.");
                    if (null != connection && connection.State == ConnectionState.Open)
                    {
                        connection.Close();
                    }

                    return;
                }
                Console.Write("\n\nНесвязный уровень\n");
                Console.WriteLine("type 'help' for help");

/*работа на несвязном уровне есть локальная работа с датасетами
1.создаешь таковой и указываешь какие в нем есть таблицы
2.создаешь адаптер которым заполняешь этот датасет
3.и билдер который сам на основании данных из адаптера -автоматически- будет генерить запросы к бд
4.сами команды изи. там ток в del/upd есть хинт что удалять/обновлять можно лишь по primary key, но даже если в Sql студии ты его накинул на таблицу, адо все равно может его не видеть и приходится явно его накидывать еще раз
5.после того как ты поработал локально с данными их нужно связать с бд. для этого нужна доп.команда adapter.Update
вы восхитительны
*/

                //несвязный уровень

                DataSet cds = new DataSet("cds");

                SqlDataAdapter adapter = new SqlDataAdapter("select * from test", connection);
                SqlCommandBuilder builder = new SqlCommandBuilder(adapter);

                adapter.Fill(cds, "test");

                DataTable dt = cds.Tables["test"];

                //table must have primary key for delete/update queries
                try {
                    DataColumn[] primary_key = new DataColumn[1];
                    primary_key[0] = cds.Tables["test"].Columns["id"];
                    dt.PrimaryKey = primary_key;
                }
                catch (Exception e) { Console.WriteLine(e.Message); }


                while (true)
                {

                    Console.Write(">");
                    com = Console.ReadLine();

                    if (com.Equals(""))
                        continue;
//=========================================================
//------------------------SELECT---------------------------
//=========================================================
                    if ('s' == com[0])
                    {
                        Console.WriteLine("select * from test");
                        PrintTable(cds.Tables["test"]);
                    }

//=========================================================
//------------------------INSERT---------------------------
//=========================================================
                    if ('i' == com[0])
                    {
                        Console.Write("->id:");
                        int tid;
                        try
                        {
                            tid = Convert.ToInt32(Console.ReadLine());
                        }
                        catch (Exception e) { Console.WriteLine(e.Message); continue; }

                        Console.Write("->name:");
                        string tname = Console.ReadLine();
                        Console.Write("->email:");
                        string tmail = Console.ReadLine();

                        DataRow row = dt.NewRow();
                        row[0] = tid;
                        row[1] = tname;
                        row[2] = tmail;

                        try { dt.Rows.Add(row); }
                        catch (Exception e) { Console.WriteLine(e.Message); continue; }

                        Console.WriteLine("row has been added");
                    }

//=========================================================
//------------------------DELETE---------------------------
//=========================================================
                    if ('d' == com[0])
                    {
                        Console.Write("->by PrimaryKey id:");
                        DataRow row = null;

                        try
                        {
                            int tid = Convert.ToInt32(Console.ReadLine());
                            row = dt.Rows.Find(tid);
                        }
                        catch (Exception e) { Console.WriteLine(e.Message); continue; }

                        try { row.Delete(); }
                        catch (Exception e) { Console.WriteLine(e.Message); continue; }

                        Console.WriteLine("row has been deleted");
                    }

//=========================================================
//------------------------UPDATE---------------------------
//=========================================================
                    if ('u' == com[0])
                    {

                        Console.Write("->new email:");
                        string newmail = Console.ReadLine();

                        int tid, indx;
                        DataRow row = null;

                        Console.Write("->by id:");
                        try
                        {
                            tid = Convert.ToInt32(Console.ReadLine());
                            row = dt.Rows.Find(tid);
                            indx = dt.Rows.IndexOf(row);
                        }
                        catch (Exception e) { Console.WriteLine(e.Message); continue; }

                        try { dt.Rows[indx]["email"] = newmail; }
                        catch (Exception e) { Console.WriteLine(e.Message); continue; }

                        Console.WriteLine("row has been updated");
                        continue;
                    }

//=========================================================
//---------------------ACCEPT-CHANGES----------------------
//=========================================================
                    if ('a' == com[0])
                    {
                        adapter.Update(cds, dt.TableName);
                        Console.WriteLine("changes have been accepted");
                    }


                    if ('h' == com[0])
                    {
                        Console.WriteLine("Available commands:");
                        Console.Write("\tselect\n\t\t* from 'test'\n");
                        Console.Write("\tinsert\n\t\tinto 'test'\n\t\t\t<value_string>\n");
                        Console.Write("\tdelete\n\t\t'test' by\n\t\t\t<primary_key>\n");
                        Console.Write("\tupdate\n\t\t'test' set 'emai'\n\t\t\t<new_email>\n\t\t\t\tby\n\t\t\t\t\t<primary_key>\n");
                        Console.WriteLine("\tAccept changes to table = [a]\n");
                        Console.Write("\tExit = [q]\n");
                    }

                    if (com.Equals("q"))
                        break;
                }

                Console.WriteLine("Closing connection. App will shut down soon.");
                connection.Close();

        } catch(Exception e) {
            Console.WriteLine(e.Message);
            Console.ReadLine();
            return;
        }

        }

    }

}