Switch to blanking tombstoned data with null, not empty string.

This accomplishes two things:

* It removes the need for an additional `channel_name_reservation` table, since `channel.name` now only contains non-null values for active channels, and
* It nicely dovetails with the idea that `null` means an unknown value in SQL-land.

1 files changed, 4 insertions, 19 deletions

diff --git a/migrations/20241017005219_retain_deleted.sql b/migrations/20241017005219_retain_deleted.sql
index 6205482..aed87f4 100644
--- a/migrations/20241017005219_retain_deleted.sql
+++ b/migrations/20241017005219_retain_deleted.sql
@@ -9,33 +9,18 @@ create table channel (
 		not null
 		primary key,
 	name text
-		not null,
+		null
+		unique,
 	created_sequence bigint
 		unique
 		not null,
 	created_at text
-		not null,
-	unique (id, name)
+		not null
 );
 
 insert into channel (id, name, created_sequence, created_at)
 select id, name, created_sequence, created_at from old_channel;
 
-create table channel_name_reservation (
-	id text
-		not null
-		unique,
-	name text
-		not null
-		unique,
-	primary key (id, name),
-	foreign key (id, name)
-		references channel (id, name)
-);
-
-insert into channel_name_reservation (id, name)
-select id, name from old_channel;
-
 create table channel_deleted (
 	id text
 		not null
@@ -64,7 +49,7 @@ create table message (
 	sent_at text
 		not null,
 	body text
-		not null
+		null
 );
 
 insert into message (id, channel, sender, sent_sequence, sent_at, body)