coder000

EF Core migration SQL, explained

Paste the script that dotnet ef migrations script produces and get a plain-English account of what it will do to your database — every table, column, index and foreign key, migration by migration — with the statements that lose data or lock tables flagged before they reach production. Reads Npgsql (PostgreSQL) and SQL Server scripts, plain or --idempotent, and says so honestly when it meets something it doesn't recognize.

Free API — explain migrations from your own tools

The same engine powers an open API (this page uses it too). No signup, no key — just a rate limit of 60 requests per minute per IP. Handy for a CI step that posts the summary on the pull request, or fails the build when a migration drops a column.

curl

curl -X POST https://www.coder000.com/api/v1/ef-migration-explain \
  -H "Content-Type: application/json" \
  -d '{"input": "START TRANSACTION;\nALTER TABLE \"Patients\" DROP COLUMN \"Phone\";\nCOMMIT;"}'

C#

var script = await File.ReadAllTextAsync("migrate.sql");
using var http = new HttpClient();
var response = await http.PostAsJsonAsync(
    "https://www.coder000.com/api/v1/ef-migration-explain",
    new { input = script });
var result = await response.Content.ReadFromJsonAsync<JsonElement>();
Console.WriteLine(result.GetProperty("output").GetString());
foreach (var w in result.GetProperty("warnings").EnumerateArray())
    Console.WriteLine($"!! {w.GetProperty("change").GetString()}");

Response shape: { "output": "…", "notes": [...], "warnings": [...] } — the uniform coder000 tool response. output is the plain-English summary, warnings are the statements that need a human (data loss, locks, constraints that can fail on existing rows), notes explain what each construct is, and every item carries a change, an explanation, and a link to the tutorial behind it.

Learn the why, not just the what

The rules this tool applies are exactly what these posts teach.

PostgreSQL with .NET and EF Core SQL & EF Core interview questions The data-type translation table Indexes, MVCC & performance Sibling tool: schema reviewer Sibling tool: T-SQL → PostgreSQL