How To: Create a Custom BC API Page

This article depicts an example and notes of how to set up an AL query in a BC extension in order to read from and write to custom tables and fields with an API call. 

How to:

1. The casing of the various values is intentional. BC is finicky about casing in some instances and SIQ uses these conventions. Entity Name and EntitySetName need to be ALL lowercase
2. The APIGroup, APIPublisher and APIVersion must match the example exactly. This will allow StockIQ to build the correct URL.
3. ODataKeyFields needs to be SystemId
4. Note the EntitySetName is the plural of the EntityName. We recommend putting an "siq" in front of your chosen name to prevent duplicate page names. 
5. Source Table is the custom table we are reading from/writing to
6. Please include fields to uniquely identify records. For example, a purchase order may have DocumentNo and LineNo. An item record may have ItemNo.
7. You must include SystemId as a field if StockIQ is writing back to your source table/field within the source table. 

///Test Page API
page77701 SiqPurchaseLineTest
{
    PageType = API;
    Caption ='Purchase Line Test API';
    APIPublisher ='StockIQ';
    APIGroup ='SIQ';
    APIVersion ='v1.0';
    EntityName ='purchaselinetest';
    EntitySetName ='purchaselinetests';
    SourceTable = "Purchase Line";
    DelayedInsert = true;
    ODataKeyFields = SystemId;

    layout
    {
        area(Content)
        {
            repeater(GroupName)
            {
                field(SystemId; Rec."SystemId"){ }
                field(DocumentType; Rec."Document Type"){ }
                field(DocumentNo; Rec."Document No."){ }
                field(LineNo; Rec."Line No."){ }
                field(YourCustomColumnA; "Your Custom Column A"){ }
            }
        }
    }
}