make it a little harder to mess up new db schema migrations

dev-tools/omdb/src/bin/omdb/db.rs

@@ -583,7 +583,7 @@ impl DbArgs {
 /// incompatible because in practice it may well not matter and it's very
 /// valuable for this tool to work if it possibly can.
 async fn check_schema_version(datastore: &DataStore) {
-    let expected_version = nexus_db_model::schema::SCHEMA_VERSION;
+    let expected_version = nexus_db_model::SCHEMA_VERSION;
     let version_check = datastore.database_schema_version().await;
 
     match version_check {

nexus/db-model/Cargo.toml

@@ -9,6 +9,7 @@ omicron-rpaths.workspace = true
 
 [dependencies]
 anyhow.workspace = true
+camino.workspace = true
 chrono.workspace = true
 derive-where.workspace = true
 diesel = { workspace = true, features = ["postgres", "r2d2", "chrono", "serde_json", "network-address", "uuid"] }
@@ -17,6 +18,7 @@ ipnetwork.workspace = true
 macaddr.workspace = true
 newtype_derive.workspace = true
 omicron-uuid-kinds.workspace = true
+once_cell.workspace = true
 parse-display.workspace = true
 # See omicron-rpaths for more about the "pq-sys" dependency.
 pq-sys = "*"
@@ -29,6 +31,7 @@ serde_json.workspace = true
 steno.workspace = true
 strum.workspace = true
 thiserror.workspace = true
+tokio.workspace = true
 uuid.workspace = true
 
 db-macros.workspace = true
@@ -42,4 +45,5 @@ sled-agent-client.workspace = true
 omicron-workspace-hack.workspace = true
 
 [dev-dependencies]
+camino-tempfile.workspace = true
 expectorate.workspace = true

nexus/db-model/src/lib.rs

@@ -67,6 +67,7 @@ mod role_assignment;
 mod role_builtin;
 pub mod saga_types;
 pub mod schema;
+mod schema_versions;
 mod service;
 mod service_kind;
 mod silo;
@@ -158,6 +159,7 @@ pub use region::*;
 pub use region_snapshot::*;
 pub use role_assignment::*;
 pub use role_builtin::*;
+pub use schema_versions::*;
 pub use semver_version::*;
 pub use service::*;
 pub use service_kind::*;

nexus/db-model/src/schema.rs

@@ -6,15 +6,6 @@
 //!
 //! NOTE: Should be kept up-to-date with dbinit.sql.
 
-use omicron_common::api::external::SemverVersion;
-
-/// The version of the database schema this particular version of Nexus was
-/// built against.
-///
-/// This should be updated whenever the schema is changed. For more details,
-/// refer to: schema/crdb/README.adoc
-pub const SCHEMA_VERSION: SemverVersion = SemverVersion::new(45, 0, 0);
-
 table! {
     disk (id) {
         id -> Uuid,