# Retrieve records with select and filter
GET [org]/api/data/v9.2/accounts?$select=name,revenue&$filter=revenue gt 1000000&$top=10
Authorization: Bearer {token}
Prefer: odata.include-annotations="*"

# Retrieve with expand (related records)
GET [org]/api/data/v9.2/accounts(00000000-0000-0000-0000-000000000001)?$select=name&$expand=contact_customer_accounts($select=fullname,emailaddress1;$top=5)

# Create a record
POST [org]/api/data/v9.2/accounts
Content-Type: application/json
{
    "name": "Contoso Ltd",
    "revenue": 5000000,
    "[email protected]": "/contacts(00000000-0000-0000-0000-000000000002)"
}

# Update a record
PATCH [org]/api/data/v9.2/accounts(00000000-0000-0000-0000-000000000001)
Content-Type: application/json
If-Match: *
{
    "name": "Contoso Ltd (Updated)",
    "revenue": 6000000
}

# Delete a record
DELETE [org]/api/data/v9.2/accounts(00000000-0000-0000-0000-000000000001)

# Batch request
POST [org]/api/data/v9.2/$batch
Content-Type: multipart/mixed;boundary=batch_boundary

--batch_boundary
Content-Type: application/http
Content-Transfer-Encoding: binary

GET accounts?$select=name&$top=5 HTTP/1.1
Accept: application/json

--batch_boundary--

<!-- Aggregation query -->
<fetch aggregate="true">
  <entity name="opportunity">
    <attribute name="estimatedvalue" alias="total_value" aggregate="sum" />
    <attribute name="ownerid" alias="owner" groupby="true" />
    <filter>
      <condition attribute="statecode" operator="eq" value="0" />
      <condition attribute="estimatedclosedate" operator="this-year" />
    </filter>
  </entity>
</fetch>

<!-- Linked entities with outer join -->
<fetch>
  <entity name="account">
    <attribute name="name" />
    <attribute name="revenue" />
    <link-entity name="contact" from="parentcustomerid" to="accountid" link-type="outer" alias="c">
      <attribute name="fullname" />
      <attribute name="emailaddress1" />
    </link-entity>
    <filter>
      <condition attribute="statecode" operator="eq" value="0" />
    </filter>
    <order attribute="name" />
  </entity>
</fetch>

// Plugin class implementing IPlugin
using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Sdk.Query;
using System;

namespace Contoso.Plugins
{
    public class AccountPreCreate : IPlugin
    {
        public void Execute(IServiceProvider serviceProvider)
        {
            // Obtain services from the service provider
            var context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));
            var serviceFactory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
            var service = serviceFactory.CreateOrganizationService(context.UserId);
            var tracingService = (ITracingService)serviceProvider.GetService(typeof(ITracingService));

            try
            {
                // Validate the target entity
                if (context.InputParameters.Contains("Target") &&
                    context.InputParameters["Target"] is Entity target)
                {
                    tracingService.Trace("AccountPreCreate: Processing {0}", target.LogicalName);

                    // Business logic: auto-set account number
                    if (!target.Contains("accountnumber"))
                    {
                        var query = new QueryExpression("account")
                        {
                            ColumnSet = new ColumnSet("accountnumber"),
                            TopCount = 1,
                            Orders = { new OrderExpression("createdon", OrderType.Descending) }
                        };

                        var results = service.RetrieveMultiple(query);
                        var nextNumber = results.Entities.Count > 0
                            ? int.Parse(results.Entities[0].GetAttributeValue<string>("accountnumber") ?? "0") + 1
                            : 1001;

                        target["accountnumber"] = nextNumber.ToString();
                        tracingService.Trace("Set account number to {0}", nextNumber);
                    }
                }
            }
            catch (Exception ex)
            {
                tracingService.Trace("AccountPreCreate Error: {0}", ex.ToString());
                throw new InvalidPluginExecutionException(
                    "An error occurred in the Account Pre-Create plugin.", ex);
            }
        }
    }
}

# Initialize plugin project
pac plugin init

# Project structure:
# MyPlugin/
# ├── MyPlugin.csproj
# ├── Plugin1.cs         # IPlugin implementation
# └── PluginBase.cs      # Optional base class

# Build and register
dotnet build
# Use Plugin Registration Tool or pac CLI to register steps

# Plugin Registration Tool steps:
# 1. Register assembly (DLL)
# 2. Register step (message, entity, stage, mode)
# 3. Register image (pre/post entity images if needed)

// Custom API plugin
namespace Contoso.Plugins
{
    public class CalculateDiscount : IPlugin
    {
        public void Execute(IServiceProvider serviceProvider)
        {
            var context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));

            // Read request parameters
            var accountId = (string)context.InputParameters["AccountId"];
            var orderTotal = (decimal)context.InputParameters["OrderTotal"];

            // Business logic
            decimal discountRate = orderTotal > 10000 ? 0.15m : 0.05m;
            decimal discountedTotal = orderTotal * (1 - discountRate);

            // Set response parameters
            context.OutputParameters["DiscountRate"] = discountRate;
            context.OutputParameters["DiscountedTotal"] = discountedTotal;
        }
    }
}

# Call custom API via Web API
POST [org]/api/data/v9.2/contoso_CalculateDiscount
Content-Type: application/json
{
    "AccountId": "00000000-0000-0000-0000-000000000001",
    "OrderTotal": 15000.00
}

# Generate early-bound entity classes
pac modelbuilder build

# Configuration in builderSettings.json:
# {
#   "entities": ["account", "contact", "opportunity"],
#   "generateActions": true,
#   "namespaces": { "account": "Contoso.DataModel" }
# }

Security Layers:
1. Security Roles     - Define table-level CRUD privileges
2. Privilege Depth    - User / Business Unit / Parent-Child BU / Organization
3. Column Security    - Restrict access to specific columns
4. Row-Level Sharing  - Share individual records with users/teams
5. Teams              - Owner teams, Access teams, AAD group teams
6. Field Masking      - Mask sensitive data in columns

Role Privilege Matrix:
┌───────────────┬────────┬──────┬────────┬────────┬────────┐
│ Entity        │ Create │ Read │ Update │ Delete │ Append │
├───────────────┼────────┼──────┼────────┼────────┼────────┤
│ Account       │ BU     │ Org  │ BU     │ User   │ BU     │
│ Contact       │ BU     │ Org  │ BU     │ User   │ BU     │
│ Opportunity   │ User   │ BU   │ User   │ None   │ User   │
└───────────────┴────────┴──────┴────────┴────────┴────────┘
Depth: User < BU < Parent-Child BU < Organization