Check if an index exists (#1828)

* feat: add method to check for index

* tests(sea-orm-migrations): add index to cake name

* tests(sea-orm-migrations): check if `has_index` works

* Update sea-orm-migration/tests/common/migration/m20220118_000001_create_cake_table.rs

* Update Cargo.toml

---------

Co-authored-by: Chris Tsang <chris.2y3@outlook.com>

sea-orm-migration/Cargo.toml

@@ -25,7 +25,7 @@ clap = { version = "4.3", features = ["env", "derive"], optional = true }
 dotenvy = { version = "0.15", default-features = false, optional = true }
 sea-orm = { version = "0.12.2", path = "../", default-features = false, features = ["macros"] }
 sea-orm-cli = { version = "0.12.2", path = "../sea-orm-cli", default-features = false, optional = true }
-sea-schema = { version = "0.14.0" }
+sea-schema = { version = "0.14.1" }
 tracing = { version = "0.1", default-features = false, features = ["log"] }
 tracing-subscriber = { version = "0.3.17", default-features = false, features = ["env-filter", "fmt"] }
 futures = { version = "0.3", default-features = false, features = ["std"] }

sea-orm-migration/src/manager.rs

@@ -136,4 +136,25 @@ impl<'c> SchemaManager<'c> {
 
         res.try_get("", "has_column")
     }
+
+    pub async fn has_index<T, I>(&self, table: T, index: I) -> Result<bool, DbErr>
+    where
+        T: AsRef<str>,
+        I: AsRef<str>,
+    {
+        let stmt = match self.conn.get_database_backend() {
+            DbBackend::MySql => MySql::has_index(table, index),
+            DbBackend::Postgres => Postgres::has_index(table, index),
+            DbBackend::Sqlite => Sqlite::has_index(table, index),
+        };
+
+        let builder = self.conn.get_database_backend();
+        let res = self
+            .conn
+            .query_one(builder.build(&stmt))
+            .await?
+            .ok_or_else(|| DbErr::Custom("Failed to check index exists".to_owned()))?;
+
+        res.try_get("", "has_index")
+    }
 }

sea-orm-migration/tests/common/migration/m20220118_000001_create_cake_table.rs

@@ -20,7 +20,18 @@ impl MigrationTrait for Migration {
                     .col(ColumnDef::new(Cake::Name).string().not_null())
                     .to_owned(),
             )
-            .await
+            .await?;
+
+        manager
+            .create_index(
+                Index::create()
+                    .name("cake_name_index")
+                    .table(Cake::Table)
+                    .col(Cake::Name)
+                    .to_owned(),
+            )
+            .await?;
+        Ok(())
     }
 
     async fn down(&self, manager: &SchemaManager) -> Result<(), DbErr> {

sea-orm-migration/tests/main.rs

@@ -182,6 +182,9 @@ where
     let migrations = Migrator::get_applied_migrations(db).await?;
     assert_eq!(migrations.len(), 6);
 
+    assert!(!manager.has_index("cake", "non_existent_index").await?);
+    assert!(manager.has_index("cake", "cake_name_index").await?);
+
     let migration = migrations.get(0).unwrap();
     assert_eq!(migration.name(), "m20220118_000001_create_cake_table");
     assert_eq!(migration.status(), MigrationStatus::Applied);