# ARX.SDK

> ARX.SDK is an entity-based data access library for .NET by MigsLab: one model (ArxEntity, ArxQueryExpression, a schema catalog) and one provider package per database (PostgreSQL, SQL Server, MySQL, MongoDB, DynamoDB). These files are for AI coding assistants: each provider's knowledge base is generated from samples that were built and run, and from the library's doc comments.

Before writing code, read the guide of the provider the project uses: it says which package to install, which usings to add, how to declare tables, and the rules an assistant must follow. ARX never creates tables: the application (or its migrations) does.

## Knowledge base per provider

- [PostgreSQL](ai/postgresql/llms.txt): ARX.SDK.PostgreSql, the most complete provider.
- [SQL Server](ai/sql/llms.txt): ARX.SDK.SQL.
- [MySQL](ai/mysql/llms.txt): ARX.SDK.MySQL.
- [MongoDB](ai/mongodb/llms.txt): ARX.SDK.MongoDb (a replica set, for transactions).
- [DynamoDB](ai/dynamodb/llms.txt): ARX.SDK.DynamoDb (a table per entity, or the single-table design).

## Optional

- [The arx-sdk skill](ai/skills/arx-sdk/SKILL.md): the same knowledge as an Agent Skills skill for coding agents, every provider in one; packed as [arx-sdk.zip](ai/skills/arx-sdk.zip).
- [Installation](installation): the packages and the setup, for people.
- [Capabilities](reference/capabilities): what each provider can do; anything else is refused with ARX8001.
- [Switching providers](guides/switching-providers): what moves between databases unchanged, and what returns different rows.