DataConnector | ComponentOne
ADO.NET provider for CSV / Querying Data
In This Topic
    Querying Data
    In This Topic

    The ADO.NET Provider for CSV implements two classes you can use to perform CRUD (Create, Read, Update, and Delete) operations: DbDataReader and C1CSVDataAdapter classes. The tabs below describe the interfaces and code implementations.

    The provider supports CRUD operations on both local CSV files and Web API CSV streams. For local CSV files, no additional configuration files are needed. However, when working with Web API CSV streams, you must utilize configuration files to specify the necessary settings for accessing and manipulating the data through the Web API. For more information on creating a configuration file, see Configuration.

    Querying With DbDataReader

    The DbDataReader class can be used to fetch data in subset increments as required. It can retrieve data quicker than the C1CSVDataAdapter as it retrieves data in pages. When you read data from the DbDataReader, it requests the succeeding page from the data source to load the result, which makes the data retrieval faster.

    The following code examples demonstrate create, read, update, and delete operations from the data source using the DbDataReader.

    Create Data

    The example adds new records by executing the Insert command.

    C#
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    static void InsertDataReader() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");
        
    using (var con = new C1CSVConnection(csvConnectionString))
    {
        con.Open();
        var sqlInsert = "Insert Into sampleCSV([year], [industry_code], [industry_name]) values (2022,'C', 'Telecommunications')";
        var cmdInsert = con.CreateCommand();
        cmdInsert.CommandText = sqlInsert;
        var result1 = cmdInsert.ExecuteNonQuery();
    } 
}

    Read Data

    The example retrieves data from the CSV file named sampleCSV.csv by executing the Select command.

    C#
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    static void ReadDataReader() 
{
    static string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");
    
    using (var con = new C1CSVConnection(csvConnectionString))
    {
        con.Open();

        // Create Read command
        var cmd = con.CreateCommand();
        cmd.CommandText = "Select * From sampleCSV";

        // Execute Read command and display fetched data
        DbDataReader rdr = cmd.ExecuteReader();
        while (rdr.Read())
        {
            Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["name"], rdr["description"]));
        }
        Console.WriteLine("Read operation successful! \n\n");
    }
}

    Update Data

    This example modifies data by executing the Update command.

    C#
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    static void UpdateDataReader() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");
                
    using (var con = new C1CSVConnection(csvConnectionString))
    {
        con.Open();
        var sqlUpdate = "Update sampleCSV set [year] = 2022 where [id] = 10";
        var cmdUpdate = con.CreateCommand();
        cmdUpdate.CommandText = sqlUpdate;
        var result2 = cmdUpdate.ExecuteNonQuery();
    }
}

    Delete Data

    This example removes data by executing the Delete command.

    C#
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    static void DeleteDataReader() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");

    using (var con = new C1CSVConnection(csvConnectionString))
    {
        con.Open();
        var sqlDelete = "Delete from sampleCSV where [id] = 90";
        var cmdDelete = con.CreateCommand();
        cmdDelete.CommandText = sqlDelete;
        var result3 = cmdDelete.ExecuteNonQuery();
    }
}

    Querying With C1CSVDataAdapter

    The C1CSVDataAdapter class can be used to retrieve a single result set containing all the data that matches a given query. The C1CSVDataAdapter uses its Fill method to fetch data from the data source. An empty DataTable instance is passed as an argument to the Fill method. Once the method returns, the DataTable instance is populated with the queried data. Since the Fill method must retrieve all the data from the data source before returning, the C1CSVDataAdapter is slower compared to the DbDataReader.

    The following code examples demonstrate create, read, update and delete operations from the data source using the C1CSVDataAdapter.

    Create Data

    The example adds new records by executing the Insert command.

    C#
    Copy Code 
    static void InsertDataAdapter() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");
    
    using (var conn = new C1CSVConnection(csvConnectionString))
    {
        //Populate DataTable
        C1CSVDataAdapter adapter = new C1CSVDataAdapter(conn, "Select * from sampleCSV");
        DataTable dataTable = new DataTable();
        adapter.Fill(dataTable);
        
        //Create Insert command
        adapter.InsertCommand = new C1CSVCommand(conn);
        adapter.InsertCommand.CommandText = "Insert Into sampleCSV([year], [industry_code], [industry_name]) values (@Year,@Industry_code, @Industry_name)";
        adapter.InsertCommand.Parameters.Add("@Year", "year");
        adapter.InsertCommand.Parameters.Add("@Industry_code", "industry_code");
        adapter.InsertCommand.Parameters.Add("@Industry_name", "industry_name");
        adapter.InsertCommand.UpdatedRowSource = UpdateRowSource.None;
        
        //Insert new row
        DataRow sampleCSVRow = dataTable.NewRow();
        sampleCSVRow["year"] = 2022;
        sampleCSVRow["industry_code"] = "C";
        sampleCSVRow["industry_name"] = "Telecommunications";
        dataTable.Rows.Add(sampleCSVRow);
        
        //Update database
        var i = adapter.Update(dataTable);
        if (i != -1)
            {
                Console.WriteLine("Insert operation successful !!! \n \n");
            }
        
        //Uncomment to display and verify results
        ShowDataTable(dataTable);
    }
}

    Read Data

    This example retrieves data by executing the Select command.

    C#
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    static void ReadDataAdapter() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");

    using (var conn = new C1CSVConnection(csvConnectionString))
    {
        //Populate DataTable
        C1CSVDataAdapter adapter = new C1CSVDataAdapter();
        
        //Create Select command
        adapter.SelectCommand = new C1CSVCommand(conn);
        adapter.SelectCommand.CommandText = "Select * from sampleCSV";
        adapter.SelectCommand.UpdatedRowSource = UpdateRowSource.None;
        
        //Populate Datatable with results using DataAdapter
        DataTable dataTable = new DataTable();
        adapter.Fill(dataTable);
        Console.WriteLine("Select operation successful !!! \n \n");
        
        //Display results
        ShowDataTable(dataTable);
    }
}

static void ShowDataTable(DataTable table, int length = 25)
{
    foreach (DataColumn col in table.Columns)
    {
        Console.Write("{0,-" + length + "}", col.ColumnName);
    }
    Console.WriteLine();

    foreach (DataRow row in table.Rows)
    {
        foreach (DataColumn col in table.Columns)
        {
            if (col.DataType.Equals(typeof(DateTime)))
                Console.Write("{0,-" + length + ":d}", row[col]);
            else if (col.DataType.Equals(typeof(decimal)))
                Console.Write("{0,-" + length + ":C}", row[col]);
            else
                Console.Write("{0,-" + length + "}", row[col]);
        }
        Console.WriteLine();
    }
}

    Update Data

    This example modifies data by executing Update command.

    C#
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    static void UpdateDataAdapter() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");
    
    using (var conn = new C1CSVConnection(csvConnectionString))
    {
        //Populate DataTable
        C1CSVDataAdapter adapter = new C1CSVDataAdapter(conn, "Select * from sampleCSV");
        DataTable dataTable = new DataTable();
        adapter.Fill(dataTable);
        
        //Create Update command
        adapter.UpdateCommand = new C1CSVCommand(conn);
        adapter.UpdateCommand.CommandText = "UPDATE sampleCSV SET year=@Year where id=@Id";
        adapter.UpdateCommand.Parameters.Add("@Year", "year");
        adapter.UpdateCommand.Parameters.Add("@Id", "id");
        adapter.UpdateCommand.UpdatedRowSource = UpdateRowSource.None;
        
        //Update existing row
        DataRow sampleCSVRow = dataTable.Rows[0];
        sampleCSVRow["id"] = 90;
        sampleCSVRow["year"] = 2022;
        
        //Update database
        var i = adapter.Update(dataTable);
        if (i != -1)
        {
            Console.WriteLine("Update operation successful !!! \n \n");
        }
        
        //Uncomment to display and verify results
        ShowDataTable(dataTable);
    }
}

    Delete Data

    This example removes data by executing Delete command.

    C#
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    static void DeleteDataAdapter() 
{
    string csvConnectionString = string.Format(@"Uri='sampleCSV.csv';Trim Values=true");
    
    using (var conn = new C1CSVConnection(csvConnectionString))
    {
        //Populate DataTable
        C1CSVDataAdapter adapter = new C1CSVDataAdapter(conn, "Select * from sampleCSV");
        DataTable dataTable = new DataTable();
        adapter.Fill(dataTable);
        
        //Create Delete command
        adapter.DeleteCommand = new C1CSVCommand(conn);
        adapter.DeleteCommand.CommandText = "Delete from sampleCSV where id = @Id";
        adapter.DeleteCommand.Parameters.Add("@Id", "id");
        adapter.DeleteCommand.UpdatedRowSource = UpdateRowSource.None;
        
        //Delete a row
        DataRow sampleCSVRow = dataTable.Rows[dataTable.Rows.Count - 1];
        sampleCSVRow.Delete();
        
        //Update database
        var i = adapter.Update(dataTable);
        if (i != -1) 
        {
            Console.WriteLine("Delete operation successful !!! \n \n");
        }
        
        //Uncomment to display and verify results
        ShowDataTable(dataTable);
    }
}