An experimental .NET Core library to more efficiently reverse engineer a SQL Server database.

All database tooling needs to reverse engineer a database. Tooling does this by querying the system catalog about the objects in the database (e.g. tables, views, triggers, store procedures, etc). Here we compare DacFx and a new strategy for reverse engineering a database: CatalogStore.

Today, when DacFx reverse engineers a database, it issues a brutal query that punches SQL Server in the face. The query is 380K in size, and does all kinds of complicated joins and fancy TSQL manipulation. See file DacFxReverseEngineeringQuery2016.sql. After viewing that file and changing your pants, you can probably guess that executing this query is very inefficient. Executing this query against an Azure 'Basic SKU' database, pegs the DTU quota, making the database unusable for a few seconds after execution.

Not only are these queries inefficient, they are expensive to maintain. All of the queries are handcrafted against a SQL version. When we release a new version of SQL, we cut and paste the query text, along with the SqlClient processing code, and then update the copy to handle the new system catalog tables and columns.

This project take a different approach. SQL Server exposes rich meta data over the system catalog. We leverage this, and code generate a library that can execute simple 'select *' statements for each system catalog table. We take the results, and place them all in a sqlite database. Then, we code generate an entity framework model over the sqlite system catalog tables. This give us a nice type-safe query experience over the system catalog, with all processing occurring on the client side. Because everything is code generated, maintenance should be lower.

This design can potentially have other benefits

• Opens the door to implement an efficient global search over all database objects.
• The sqlite system catalog database can be persisted and cached on disk.
• Intellisense cache

Initial benchmarks indicate CatalogStore is in-line with DacFx when reverse engineering small databases. However as object counts grow, CatalogStore scales better than DacFx.

• The code generated CatalogStore

• Code generates the files in the Microsoft.SqlServer.CatalogStore\CodeGen folder
• Uses the Catalog.Whitelist.txt to get all system catalog tables used for reverse engineering.
• Generates and caches the system catalog list (e.g. Catalog.2005.txt) and catalog xml meta data files (e.g Catalog.2005.xml) for each SQL Server version.

• Has tests to compare the execution of the DacFx query with the CatalogStore version.

• Uses ScriptDom to parse the DacFx reverse engineering queries for Azure and SQL 2016, and generates the Catalog.Whitelist.txt file, which is input into the code generation process. This way, both DacFx and CatalogStore query the same tables.

• Explicit mapping of primary keys
• Figure out how to handle sql_variants - currently not mapped
• Handle timespan column types - currently not mapped
• Introduce loading profiles: lazy, object explorer, reverse engineer