PostgreSQL Data Binding

27 Mar 202311 minutes to read

This section describes how to use Npgsql EntityFrameworkCore PostgreSQL to retrieve data from a PostgreSQL database and bind it to the Blazor Pivot Table.

Connecting a PostgreSQL to a Syncfusion Blazor Pivot Table

1. Create a simple Blazor Pivot Table by following the “Getting Started” documentation link.

2. To connect a PostgreSQL using the Npgsql EntityFrameworkCore PostgreSQL in our application, we need to install the Npgsql.EntityFrameworkCore.PostgreSQL NuGet package. To do so, open the NuGet package manager of the project solution, search for the package Npgsql.EntityFrameworkCore.PostgreSQL and install it.

3. Next, in the Index.razor page, under the OnInitialized method, connect to PostgreSQL database. You can get the specified database by using the NpgsqlConnection. Following that, the NpgsqlCommand is used to retrieve the desired collection from the database. Then populate the data collection from the NpgsqlCommand into a list using the Read method of NpgsqlDataReader.

4. Finally, bind the list to the DataSource property in the PivotViewDataSourceSettings and configure the report to use the PostgreSQL data.

@using System.Data
@using Npgsql
@using Syncfusion.Blazor.PivotView

<SfPivotView TValue="PostgreSQLService" Width="1000" Height="300" ShowFieldList="true">
    <PivotViewDataSourceSettings TValue="PostgreSQLService" DataSource="@dataSource" ExpandAll=false EnableSorting=true>
        <PivotViewColumns>
            <PivotViewColumn Name="openinghours_practice" Caption="Openinghours Practice"></PivotViewColumn>
            <PivotViewColumn Name="closinghours_practice" Caption="Closinghours Practice"></PivotViewColumn>
        </PivotViewColumns>
        <PivotViewRows>
            <PivotViewRow Name="servicetype" Caption="Service Type"></PivotViewRow>
            <PivotViewRow Name="servicecategory" Caption="Service Category"></PivotViewRow>
        </PivotViewRows>
        <PivotViewValues>
            <PivotViewValue Name="revenue" Caption="Revenue"></PivotViewValue>
        </PivotViewValues>
        <PivotViewFormatSettings>
            <PivotViewFormatSetting Name="revenue" Format="C0"></PivotViewFormatSetting>
        </PivotViewFormatSettings>
    </PivotViewDataSourceSettings>
    <PivotViewGridSettings ColumnWidth="120"></PivotViewGridSettings>
</SfPivotView>

@code {
    private List<PostgreSQLService> dataSource { get; set; }

    protected override void OnInitialized()
    {
        List<PostgreSQLService> postGreSqlData = new List<PostgreSQLService>();
        // Replace with your own connection string.
        NpgsqlConnection connection = new NpgsqlConnection("<Enter your valid connection string here>");
        connection.Open();
        NpgsqlCommand cmd = new NpgsqlCommand("SELECT * FROM apxtimestamp", connection);
        using (NpgsqlDataReader reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                postGreSqlData.Add(new PostgreSQLService()
                {
                    openinghours_practice = (TimeSpan)reader["openinghours_practice"],
                    closinghours_practice = (TimeSpan)reader["closinghours_practice"],
                    servicetype = reader["servicetype"].ToString(),
                    servicecategory = reader["servicecategory"].ToString(),
                    revenue = Convert.ToInt32(reader["revenue"])
                });
            }
        }
        connection.Close();   
        this.dataSource = postGreSqlData;
    }

    public class PostgreSQLService
    {
        public TimeSpan openinghours_practice { get; set; }
        public TimeSpan closinghours_practice { get; set; }
        public string servicetype { get; set; }
        public string servicecategory { get; set; }
        public int revenue { get; set; }
    }
}

When you run the application, the resultant pivot table will look like this.

Connecting a PostgreSQL to a Syncfusion Blazor Pivot Table via Web API service

Create a Web API service to fetch PostgreSQL data

1. Open Visual Studio and create an ASP.NET Core Web App project type, naming it MyWebService. To create an ASP.NET Core Web application, follow the documentation link.

2. To connect a PostgreSQL using the Npgsql EntityFrameworkCore PostgreSQL in our application, we need to install the Npgsql.EntityFrameworkCore.PostgreSQL NuGet package. To do so, open the NuGet package manager of the project solution, search for the package Npgsql.EntityFrameworkCore.PostgreSQL and install it.

3. Create a Web API controller (aka, PivotController.cs) file under Controllers folder that helps to establish data communication with the Pivot Table.

4. In the Web API controller (aka, PivotController), NpgsqlConnection helps to connect the PostgreSQL database. Next, using NpgsqlCommand and NpgsqlDataAdapter you can process the desired query string and retrieve data from the PostgreSQL database. The Fill method of the NpgsqlDataAdapter is used to populate the retrieved data into a DataTable as shown in the following code snippet.

using Microsoft.AspNetCore.Mvc;
using Newtonsoft.Json;
using System.Data;
using Npgsql;

namespace MyWebService.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class PivotController : ControllerBase
    {
        private dynamic GetPostgreSQLResult()
        {
            // Replace with your own connection string.
            NpgsqlConnection connection = new NpgsqlConnection("<Enter your valid connection string here>");
            connection.Open();
            NpgsqlCommand command = new NpgsqlCommand("SELECT * FROM apxtimestamp", connection);
            NpgsqlDataAdapter dataAdapter = new NpgsqlDataAdapter(command);
            DataTable dataTable = new DataTable();
            dataAdapter.Fill(dataTable);
            connection.Close();
            return dataTable;
        }
    }
}

5. In the Get() method of the PivotController.cs file, the GetPostgreSQLResult method is used to retrieve the PostgreSQL data as a DataTable, which is then serialized into JSON string using JsonConvert.SerializeObject().

using Microsoft.AspNetCore.Mvc;
using Newtonsoft.Json;
using System.Data;
using Npgsql;

namespace MyWebService.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class PivotController : ControllerBase
    {
        [HttpGet(Name = "GetPostgreSQLResult")]
        public object Get()
        {
            return JsonConvert.SerializeObject(GetPostgreSQLResult());
        }

        private dynamic GetPostgreSQLResult()
        {
            // Replace with your own connection string.
            NpgsqlConnection connection = new NpgsqlConnection("<Enter your valid connection string here>");
            connection.Open();
            NpgsqlCommand command = new NpgsqlCommand("SELECT * FROM apxtimestamp", connection);
            NpgsqlDataAdapter dataAdapter = new NpgsqlDataAdapter(command);
            DataTable dataTable = new DataTable();
            dataAdapter.Fill(dataTable);
            connection.Close();
            return dataTable;
        }
    }
}

6. Run the application and it will be hosted within the URL https://localhost:44378.

7. Finally, the retrieved data from PostgreSQL which is in the form of JSON can be found in the Web API controller available in the URL link https://localhost:44378/Pivot, as shown in the browser page below.

Connecting the Pivot Table to a PostgreSQL using the Web API service

1. Create a simple Blazor Pivot Table by following the “Getting Started” documentation link.

2. Map the hosted Web API’s URL link https://localhost:44378/Pivot to the Pivot Table in Index.razor by using the Url property under PivotViewDataSourceSettings. This Url property aids in the de-serialization of PostgreSQL data into instances of your model data class (aka, TValue=”PostgreSQLService”) while bound to the pivot table.

@using Syncfusion.Blazor.PivotView

<SfPivotView TValue="PostgreSQLService" Width="1000" Height="300" ShowFieldList="true">
    <PivotViewDataSourceSettings TValue="PostgreSQLService" Url="https://localhost:44378/Pivot" ExpandAll=false EnableSorting=true>
        <PivotViewColumns>
            <PivotViewColumn Name="openinghours_practice" Caption="Openinghours Practice"></PivotViewColumn>
            <PivotViewColumn Name="closinghours_practice" Caption="Closinghours Practice"></PivotViewColumn>
        </PivotViewColumns>
        <PivotViewRows>
            <PivotViewRow Name="servicetype" Caption="Service Type"></PivotViewRow>
            <PivotViewRow Name="servicecategory" Caption="Service Category"></PivotViewRow>
        </PivotViewRows>
        <PivotViewValues>
            <PivotViewValue Name="revenue" Caption="Revenue"></PivotViewValue>
        </PivotViewValues>
        <PivotViewFormatSettings>
            <PivotViewFormatSetting Name="revenue" Format="C0"></PivotViewFormatSetting>
        </PivotViewFormatSettings>
    </PivotViewDataSourceSettings>
    <PivotViewGridSettings ColumnWidth="120"></PivotViewGridSettings>
</SfPivotView>

@code {
    public class PostgreSQLService
    {
        public TimeSpan openinghours_practice { get; set; }
        public TimeSpan closinghours_practice { get; set; }
        public string servicetype { get; set; }
        public string servicecategory { get; set; }
        public int revenue { get; set; }
    }
}

When you run the application, the resultant pivot table will look like this.

In this GitHub repository, you can find our Blazor Pivot Table sample for binding data from a PostgreSQL using the Web API service.