How to load PDF document from database into PDF viewer

<form id="form1" runat="server" >
    <div>
        <label>Enter the document name:</label>
        <input id="documentName" />
        <button id="load" onclick="loadDocument(event)" type="button">Load</button>
        <div class="content-container-fluid">
        <div class="row">
            <div class="cols-sample-area">
                    <div class="control">
                        <div id="pdfviewer">
                             <ej:pdfviewer id="pdfviewer1" Height="800"  ServiceUrl="/api/PdfViewer" runat="server">
                             </ej:pdfviewer>
                            </div>
                        </div>
                </div>
            </div>
            </div>
        </div>                                        
    </form>

function loadDocument(event) {
//To send the provided file name to the web API controller.
            var documentName = $("#documentName").val();
            var jsonObject = new Object();
            if (documentName != "") {
                jsonObject['documentName'] = documentName;
                var jsonResult = JSON.stringify(jsonObject);
                $.ajax({
                    type: "POST",
                    url: '../api/PdfViewer/DocumentRetrieve',
                    crossDomain: true,
                    contentType: 'application/json; charset=utf-8',
                    dataType: 'json',
                    data: jsonResult,
                    traditional: true,
                    success: function (data) {
//returns the PDF document data as base 64 string
                        openDoc(data);
                    }
                });
            }
        }
        function openDoc(data) {           
            var obj = $("#pdfviewer1").data("ejPdfViewer");
//load the PDF document in PDF viewer
            obj.load(data);
        }            

public object DocumentRetrieve(Dictionary<string, string> jsonResult)
        {
            string documentID = jsonResult["documentName"];
            string constr = System.Configuration.ConfigurationManager.ConnectionStrings["PdfDocument"].ConnectionString;
            System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(constr);
//searches for the PDF document from the Database
            var query = "select Data from PdfDocuments where DocumentName = '" + documentID + "'";
            System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand(query);
            cmd.Connection = con;
            con.Open();
            System.Data.SqlClient.SqlDataReader read = cmd.ExecuteReader();
            read.Read();
// Reads the PDF document data as byte array from the database
            byte[] byteArray = (byte[])read["Data"];
//converts byte array into base64 string
            return "data:application/pdf;base64," + Convert.ToBase64String(byteArray);
        }