PostgreSQL Provider

The PostgreSQL provider offers full relational database support with Npgsql-based query execution, event sourcing integration, inbox/outbox patterns, and Change Data Capture.

Before You Start

.NET 10.0
A PostgreSQL instance (local or cloud-hosted)
Familiarity with data access and IDb interface

Installation

dotnet add package Excalibur.Data.Postgres

Dependencies: Excalibur.Data.Abstractions, Npgsql

Quick Start

using Microsoft.Extensions.DependencyInjection;

services.AddPostgresDataExecutors(() => new NpgsqlConnection(connectionString));

Registration Methods

Method	What It Registers	Key Options
`data.UsePostgres(Action<IPostgresDataBuilder>)`	Core data executors	Builder with 5 connection overloads
`es.UsePostgres(Action<IPostgresEventSourcingBuilder>)`	`IEventStore` + `ISnapshotStore`	Builder with 5 connection overloads
`saga.UsePostgres(Action<IPostgresSagaBuilder>)`	`ISagaStore`	Builder with 5 connection + SchemaName, TableName
`inbox.UsePostgres(Action<IPostgresInboxBuilder>)`	`IInboxStore`	Builder with 5 connection + SchemaName, TableName, MaxRetryCount
`outbox.UsePostgres(Action<IPostgresOutboxBuilder>)`	`IOutboxStore`	Builder with 5+ connection + SchemaName, TableName, DeadLetterTableName
`le.UsePostgres(Action<IPostgresLeaderElectionBuilder>)`	`ILeaderElection`	Builder with 5 connection + LockKey
`cdc.UsePostgres(Action<IPostgresCdcBuilder>)`	CDC processor	Builder with 5 connection + PublicationName, ReplicationSlotName
`compliance.UsePostgres(Action<IPostgresComplianceBuilder>)`	Erasure + DataInventory + LegalHold	Builder with 5 connection overloads
`AddPostgresAuditStore(Action<PostgresAuditOptions>)` / `AddPostgresAuditStore(IConfiguration)`	`IAuditStore`	`PostgresAuditOptions` (connection, schema, table)
`AddPostgresProjectionStore<T>(opts)`	`IProjectionStore<T>`	`ConnectionString`, `TableName`

The event store writes each event's declared [MessageName] -- not its CLR type name -- to the stored event-type field, and resolves that name back to a CLR type through the registered event-type registry on read. See Stable Message Names.

Batch Projection Registration

services.AddPostgresProjections(connectionString, projections =>
{
    projections.Add<OrderSummary>();
    projections.Add<CustomerProfile>(o => o.TableName = "customer_views");
});

Change Data Capture

services.AddCdcProcessor(cdc =>
{
    cdc.UsePostgres(pg => pg.ConnectionString(connectionString))
       .TrackTable("public.orders", t => t.MapAll<OrderChangedEvent>());
});

Data Request Pattern

public class GetCustomerRequest : DataRequest<Customer?>
{
    public GetCustomerRequest(Guid customerId)
    {
        Command = new CommandDefinition(
            "SELECT * FROM customers WHERE id = @Id",
            new { Id = customerId });
    }
}

Before You Start​

Installation​

Quick Start​

Registration Methods​

Batch Projection Registration​

Change Data Capture​

Data Request Pattern​

See Also​