Bound unique constraint row checks

drizzle-kit/src/ext/api.ts

@@ -104,7 +104,6 @@ export type SelectResolverInput = {
 	entity: {
 		type: 'createUniqueConstraint';
 		name: string;
-		count: number;
 		tableName: string;
 	};
 	items: string[];
@@ -363,17 +362,15 @@ async function maybeAddUniqueTruncateStatement({
 
 	const unique = statement.unique;
 	const tableName = quotedIdentifier({ schema: unique.schema, name: unique.table });
-	const res = await db.query<{ count: string | number }>(`select count(*) as count from ${tableName}`);
-	const count = Number(res[0]?.count ?? 0);
-	if (count <= 0) {
+	const rows = await db.query(`select 1 from ${tableName} limit 1`);
+	if (rows.length === 0) {
 		return;
 	}
 
 	const { data } = await selectResolver({
 		entity: {
 			type: 'createUniqueConstraint',
 			name: unique.name,
-			count,
 			tableName: unique.table,
 		},
 		items: ['no', 'yes'],

drizzle-kit/tests/api.test.ts

@@ -129,4 +129,35 @@ describe('Replit compatibility API', () => {
 		expect(result.statementsToExecute).toEqual(['CREATE SCHEMA "private";\n']);
 		expect(result.shouldAskForApprove).toBe(false);
 	});
+
+	test('uses a bounded row-existence query for unique constraints', async () => {
+		const db = { query: vi.fn().mockResolvedValue([{}]) };
+		const selectResolver = vi.fn().mockResolvedValue({
+			data: { index: 0, value: 'no' },
+		});
+		const statements: JsonStatement[] = [{
+			type: 'add_unique',
+			unique: {
+				entityType: 'uniques',
+				schema: 'public',
+				table: 'users',
+				name: 'users_email_unique',
+				nameExplicit: true,
+				columns: ['email'],
+				nullsNotDistinct: false,
+			},
+		}];
+
+		await pgSuggestions(db, statements, selectResolver);
+
+		expect(db.query).toHaveBeenCalledWith('select 1 from "users" limit 1');
+		expect(selectResolver).toHaveBeenCalledWith({
+			entity: {
+				type: 'createUniqueConstraint',
+				name: 'users_email_unique',
+				tableName: 'users',
+			},
+			items: ['no', 'yes'],
+		});
+	});
 });