Add Check If Database And Schema Are Not In Sync as a Prisma TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1429 TILs and counting..._
+_1430 TILs and counting..._
 
 ---
 
@@ -824,6 +824,7 @@ _1429 TILs and counting..._
 
 - [Apply Separate Formatting With A Blank Line](prisma/apply-separate-formatting-with-a-blank-line.md)
 - [Batch Insert Records With createMany](prisma/batch-insert-records-with-create-many.md)
+- [Check If Database And Schema Are Not In Sync](prisma/check-if-database-and-schema-are-not-in-sync.md)
 - [Configure Client To Log SQL Queries](prisma/configure-client-to-log-sql-queries.md)
 - [Execute A Raw SQL Query](prisma/execute-a-raw-sql-query.md)
 - [Grab A Limited Set Of Records](prisma/grab-a-limited-set-of-records.md)

prisma/check-if-database-and-schema-are-not-in-sync.md

@@ -0,0 +1,37 @@
+# Check If Database And Schema Are Not In Sync
+
+The [`prisma migrate
+diff`](https://www.prisma.io/docs/orm/reference/prisma-cli-reference#migrate-diff)
+command is a versatile tool that can be used to check if there is a difference
+between two sources. In this case, we want to check if our database is in sync
+with the `schema.prisma` file for our project.
+
+If we have made changes to the schema file, but haven't yet migrated or pushed
+those changes to our local database, then we want to be notified of that
+mismatch.
+
+We'll point at the schema file with `--to-schema-datamodel` and at our local
+database with `--from-url`.
+
+```bash
+❯ npx prisma migrate diff \
+    --to-schema-datamodel ./prisma/schema.prisma \
+    --from-url mysql://root@localhost:3309/kcd-products
+
+[*] Changed the `User` table
+  [+] Added column `metadata`
+```
+
+In the case where there is a different, we see an output summary of the diff.
+
+Let's say we've applied our changes (`prisma db push`) to our local database.
+If we now run that same command again, we can see that no difference is
+detected and our database is in sync with our schema.
+
+```bash
+❯ npx prisma migrate diff \
+    --to-schema-datamodel ./prisma/schema.prisma \
+    --from-url mysql://root@localhost:3309/kcd-products
+
+No difference detected.
+```