Data seeding

As explained in Building Web APIs with ASP.NET Core

Database seeding is the process of populating a database with an initial, required, or imported set of records.

Data seeding populates a database with an initial, required, or imported set of records. In a board-game API, it replaces temporary dummy data with records loaded into real database tables, allowing normal retrieval and later CRUD operations. section 5.2.2 section 5.3

A practical CSV seeding workflow consists of these steps:

• Place the CSV file in a project folder and install a package that maps CSV rows to C# objects. section 5.3
• Define a BggRecord POCO, then create a SeedController action dedicated to importing the data. section 5.3
• Configure CsvHelper, open the file with StreamReader, parse records, and map each record to EF Core entities. section 5.3.5
• Skip rows without required identifiers or names and skip records already present in the database. section 5.3.5
• Save the new entities and return counts for imported tables and skipped rows. section 5.3.5

An idempotent seed endpoint

Expose the import action through HTTP PUT, disable response caching, and check existing records before insertion. Repeating the request therefore leaves already imported data unchanged. Keep unrelated initialization tasks separate: board-game data can use /Seed/BoardGameData, while roles and users use /Seed/AuthData. section 5.3.5 section 9.4.2

Figure 5.1 BoardGameController’s Get() method returning an empty “data” array

Use the empty data-array response to verify why seeding is necessary after switching retrieval from dummy data to a database query. section 5.2.2

How Building Web APIs with ASP.NET Core covers it

How deep it goes

Details file placement, mapping, parsing, validation, duplicate checks, persistence, and endpoint design, but not deployment automation.

Examples

Uses a board-game CSV import, SeedController endpoints, duplicate checks, skipped-row counts, and role initialization.

What it assumes

Assumes familiarity with C#, ASP.NET Core controllers, databases, and EF Core while teaching CSV mapping and idempotent requests.

What you can do after

Build it from scratch by implementing an idempotent CSV import endpoint that maps records into EF Core entities.

How it connects

Connects CSV parsing, POCO mapping, EF Core, HTTP idempotency, controllers, and CRUD operations.

liveBookmanning.com

Read Building Web APIs with ASP.NET Core on liveBook Get the book at manning.com

Also explained in

• 

  liveBookmanning.com
  Pro ASP.NET Core 7, Tenth EditionSeed data is initial data inserted into an application's database to establish required records and state.

Compare how 2 books explain data seeding →

Related concepts

• databaseuses · A database is an organized collection of persistent data managed by software for storage, retrieval, querying, and modification.
• Entity Framework Coreuses · Entity Framework Core is a cross-platform object-relational mapping framework for .NET that enables applications to query and persist data through .NET objects and APIs.
• datasetuses · A dataset is an organized collection of related data items, records, or observations treated as a unit for storage, processing, analysis, or computation.
• SaveChangesused by · SaveChanges is an Entity Framework Core DbContext method that persists tracked entity changes to the database.
• configurationuses · A specification of settings, parameters, or component relationships that determines how a system, application, model, or process is structured or operates.

This explainer was generated by Manning's knowledge graph from the text of Building Web APIs with ASP.NET Core. The section links point to the parts of the book it draws on.