sql: clarify UPDATE test cases with intermediate constraint violations

src/sql/engine/local.rs

@@ -190,9 +190,7 @@ impl<E: storage::Engine> super::Transaction for Transaction<E> {
                 }
                 if let Some(source_id) = source_ids.into_iter().next() {
                     return errinput!(
-                        "row referenced by {}.{} for {}.{}={source_id}",
-                        source.name,
-                        column.name,
+                        "primary key referenced by {}.{}={source_id}",
                         source.name,
                         source.columns[source.primary_key].name
                     );

src/sql/testscripts/writes/delete_reference

@@ -24,8 +24,8 @@ ok
 !> DELETE FROM ref
 !> DELETE FROM ref WHERE id = 1
 ---
-Error: invalid input: row referenced by name.ref_id for name.id=1
-Error: invalid input: row referenced by name.ref_id for name.id=1
+Error: invalid input: primary key referenced by name.id=1
+Error: invalid input: primary key referenced by name.id=1
 
 > SELECT * FROM ref
 ---
@@ -97,7 +97,7 @@ ok
 # Deleting a referenced row errors.
 !> DELETE FROM self WHERE id = 2
 ---
-Error: invalid input: row referenced by self.self_id for self.id=3
+Error: invalid input: primary key referenced by self.id=3
 
 # Deleting an unreferenced row works.
 > DELETE FROM self WHERE id = 4

src/sql/testscripts/writes/update_expression

@@ -30,23 +30,19 @@ ok
 2, 3, 12
 
 # This is also true with primary key updates.
-# TODO: fix this
-!> UPDATE test SET id = id + 1, value = id, quantity = value
+> UPDATE test SET id = id - 1, value = id, quantity = value
 > SELECT * FROM test
 ---
-Error: invalid input: primary key 1 already exists
-0, 1, 10
-1, 2, 11
-2, 3, 12
+-1, 0, 1
+0, 1, 2
+1, 2, 3
 
 # UPDATE expressions respect constraints.
-> UPDATE test SET value = NULL WHERE id = 1
+> UPDATE test SET value = NULL WHERE id = 0
 > SELECT * FROM test
----
-0, 1, 10
-1, NULL, 11
-2, 3, 12
-
 !> UPDATE test SET quantity = value
 ---
+-1, 0, 1
+0, NULL, 2
+1, 2, 3
 Error: invalid input: NULL value not allowed for column quantity

src/sql/testscripts/writes/update_primary_key

@@ -136,9 +136,9 @@ Error: invalid input: primary key ABC already exists
 Error: invalid input: primary key Hi! 👋 already exists
 Error: invalid input: invalid primary key NULL
 
-# UPDATE can modify multiple primary keys whose intermediate keys conflict,
-# as long as the final set doesn't conflict.
-# TODO: fix this
+# Primary key updates error if intermediate row updates violate primary key
+# uniqueness, even if the final state wouldn't violate the constraints. This is
+# also true with Postgres.
 > SELECT * FROM "int"
 ---
 0
@@ -148,26 +148,9 @@ Error: invalid input: invalid primary key NULL
 ---
 Error: invalid input: primary key 1 already exists
 
-# UPDATE can modify multiple primary keys that have foreign key references
-# as long as the final set of primary keys still satisfy the references.
-# We test this by swapping primary keys 0 <-> 1 in a single UPDATE.
-# TODO: this shouldn't error.
-> CREATE TABLE ref (id INT PRIMARY KEY, int_id INTEGER REFERENCES "int")
-> INSERT INTO ref VALUES (0, 0), (1, 1)
----
-ok
-
-!> UPDATE "int" SET id = 1 - id
+# The updates happen in primary key order, so the reverse update does work.
+> UPDATE "int" SET id = id - 1
 > SELECT * FROM "int"
 ---
-Error: invalid input: row referenced by ref.int_id for ref.id=0
-0
-1
-
-# If the UPDATE leaves a foreign key dangling, it should error.
-!> UPDATE "int" SET id = id - 1
-> SELECT * FROM "int"
----
-Error: invalid input: row referenced by ref.int_id for ref.id=0
+-1
 0
-1

src/sql/testscripts/writes/update_reference

@@ -158,11 +158,31 @@ storage delete mvcc:TxnActive(26) ["\x01\x00\x00\x00\x00\x00\x00\x00\x1a"]
 !> UPDATE self SET id = 4 WHERE id = 1
 !> UPDATE self SET id = 4 WHERE id = 2
 ---
-Error: invalid input: row referenced by self.self_id for self.id=2
-Error: invalid input: row referenced by self.self_id for self.id=3
+Error: invalid input: primary key referenced by self.id=2
+Error: invalid input: primary key referenced by self.id=3
 
 # Not even when only this row points to itself.
 > UPDATE self SET self_id = NULL WHERE id > 1
 !> UPDATE self SET id = 4 WHERE id = 1
 ---
 Error: invalid input: reference 1 not in table self
+
+# Updates can't violate foreign key references in intermediate states even if
+# the final state retains foreign key integrity. Postgres can't either.
+> SELECT * FROM "int"
+---
+-1
+0
+1
+
+> INSERT INTO name (id, "int") VALUES (2, -1), (3, 0), (4, 1)
+> SELECT * FROM name
+---
+1, NULL, NULL, NULL, NULL
+2, NULL, -1, NULL, NULL
+3, NULL, 0, NULL, NULL
+4, NULL, 1, NULL, NULL
+
+!> UPDATE "int" SET id = -id
+---
+Error: invalid input: primary key referenced by name.id=2

src/sql/testscripts/writes/update_unique

@@ -260,3 +260,15 @@ storage delete mvcc:TxnActive(23) ["\x01\x00\x00\x00\x00\x00\x00\x00\x17"]
 ---
 1, NULL, NULL, inf, case
 2, NULL, NULL, -inf, CaSe
+
+# An UPDATE errors if intermediate states violate the uniqueness constraints,
+# even if the final state wouldn't. This is the same in Postgres.
+> UPDATE "unique" SET "bool" = id = 2
+> SELECT * FROM "unique"
+---
+1, FALSE, NULL, inf, case
+2, TRUE, NULL, -inf, CaSe
+
+!> UPDATE "unique" SET "bool" = NOT "bool"
+---
+Error: invalid input: value TRUE already in unique column bool