diff --git a/src/test/kotlin/kestrel/store/sql/DiskExecutorTest.kt b/src/test/kotlin/kestrel/store/sql/DiskExecutorTest.kt
index 3ae751a..d25030f 100644
--- a/src/test/kotlin/kestrel/store/sql/DiskExecutorTest.kt
+++ b/src/test/kotlin/kestrel/store/sql/DiskExecutorTest.kt
@@ -3012,3 +3012,158 @@ class DiskExecutorTest {
         assertFailsWith<KestrelException> { db.run("SELECT * FROM seniors") }
     }
 
+    @Test
+    fun columnLevelCheckAcceptsSatisfyingRowsAndRejectsViolatingOnes() {
+        val db = newDatabase()
+        db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, age INTEGER CHECK (age > 0))")
+        assertEquals(InsertResult(1), db.run("INSERT INTO t VALUES (1, 30)").single())
+        val error = assertFailsWith<KestrelException> { db.run("INSERT INTO t VALUES (2, -5)") }
+        assertTrue(error.message!!.contains("CHECK"))
+    }
+
+    @Test
+    fun checkPassesWhenExpressionIsUnknownBecauseOfNull() {
+        val db = newDatabase()
+        db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, age INTEGER CHECK (age > 0))")
+        // three-valued logic: NULL > 0 is UNKNOWN, not FALSE, so the row is accepted
+        assertEquals(InsertResult(1), db.run("INSERT INTO t (id) VALUES (1)").single())
+    }
+
+    @Test
+    fun tableLevelCheckCanSpanMultipleColumns() {
+        val db = newDatabase()
+        db.run("CREATE TABLE ranges (id INTEGER PRIMARY KEY, low INTEGER, high INTEGER, CHECK (low <= high))")
+        assertEquals(InsertResult(1), db.run("INSERT INTO ranges VALUES (1, 1, 10)").single())
+        assertFailsWith<KestrelException> { db.run("INSERT INTO ranges VALUES (2, 10, 1)") }
+    }
+
+    @Test
+    fun multipleCheckConstraintsAllMustBeSatisfied() {
+        val db = newDatabase()
+        db.run(
+            "CREATE TABLE t (id INTEGER PRIMARY KEY, age INTEGER CHECK (age >= 0), " +
+                "score INTEGER CHECK (score BETWEEN 0 AND 100))"
+        )
+        assertEquals(InsertResult(1), db.run("INSERT INTO t VALUES (1, 30, 90)").single())
+        assertFailsWith<KestrelException> { db.run("INSERT INTO t VALUES (2, 30, 150)") }
+        assertFailsWith<KestrelException> { db.run("INSERT INTO t VALUES (3, -1, 90)") }
+    }
+
+    @Test
+    fun checkIsEnforcedOnUpdateToo() {
+        val db = newDatabase()
+        db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, age INTEGER CHECK (age > 0))")
+        db.run("INSERT INTO t VALUES (1, 30)")
+        assertFailsWith<KestrelException> { db.run("UPDATE t SET age = -1 WHERE id = 1") }
+        assertEquals(UpdateResult(1), db.run("UPDATE t SET age = 40 WHERE id = 1").single())
+    }
+
+    @Test
+    fun checkRejectsAggregateFunctions() {
+        val db = newDatabase()
+        assertFailsWith<KestrelException> {
+            db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, amount INTEGER CHECK (SUM(amount) > 0))")
+        }
+    }
+
+    @Test
+    fun checkRejectsSubqueries() {
+        val db = newDatabase()
+        db.run("CREATE TABLE other (id INTEGER PRIMARY KEY)")
+        assertFailsWith<KestrelException> {
+            db.run("CREATE TABLE t (id INTEGER PRIMARY KEY CHECK (id IN (SELECT id FROM other)))")
+        }
+    }
+
+    @Test
+    fun checkRejectsUnknownColumn() {
+        val db = newDatabase()
+        assertFailsWith<KestrelException> {
+            db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, CHECK (nope > 0))")
+        }
+    }
+
+    @Test
+    fun checkCanReferenceStringAndCallExpressions() {
+        val db = newDatabase()
+        db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT CHECK (LENGTH(name) > 0))")
+        assertEquals(InsertResult(1), db.run("INSERT INTO t VALUES (1, 'ada')").single())
+        assertFailsWith<KestrelException> { db.run("INSERT INTO t VALUES (2, '')") }
+    }
+
+    @Test
+    fun checkDefinitionSurvivesClosingAndReopeningTheCatalog() {
+        val db = newDatabase()
+        db.run("CREATE TABLE t (id INTEGER PRIMARY KEY, age INTEGER CHECK (age > 0), CHECK (id > 0))")
+        db.run("INSERT INTO t VALUES (1, 30)")
+        db.reopen()
+
+        assertEquals(InsertResult(1), db.run("INSERT INTO t VALUES (2, 40)").single())
+        assertFailsWith<KestrelException> { db.run("INSERT INTO t VALUES (3, -1)") }
+        assertFailsWith<KestrelException> { db.run("UPDATE t SET age = -5 WHERE id = 1") }
+
+        db.reopen()
+        assertFailsWith<KestrelException> { db.run("INSERT INTO t VALUES (4, -1)") }
+        assertEquals(2, db.select("SELECT * FROM t").rows.size)
+    }
+
+    private fun Database.seedDepartmentsAndEmployees() {
+        run("CREATE TABLE departments (id INTEGER PRIMARY KEY, name TEXT NOT NULL)")
+        run(
+            "CREATE TABLE employees (" +
+                "id INTEGER PRIMARY KEY, name TEXT NOT NULL, dept_id INTEGER REFERENCES departments(id))"
+        )
+        run("INSERT INTO departments VALUES (1, 'eng'), (2, 'ops')")
+    }
+
+    private fun Database.seedCascadeDepartments() {
+        run("CREATE TABLE departments (id INTEGER PRIMARY KEY, name TEXT NOT NULL)")
+        run(
+            "CREATE TABLE employees (id INTEGER PRIMARY KEY, name TEXT NOT NULL, " +
+                "dept_id INTEGER REFERENCES departments(id) ON DELETE CASCADE ON UPDATE CASCADE)"
+        )
+        run("INSERT INTO departments VALUES (1, 'eng'), (2, 'ops')")
+        run("INSERT INTO employees VALUES (1, 'ada', 1), (2, 'linus', 1), (3, 'grace', 2)")
+    }
+
+    private fun Database.seedSetNullDepartments(childNotNull: Boolean) {
+        run("CREATE TABLE departments (id INTEGER PRIMARY KEY, name TEXT NOT NULL)")
+        val childColumn = if (childNotNull) "dept_id INTEGER NOT NULL" else "dept_id INTEGER"
+        run(
+            "CREATE TABLE employees (id INTEGER PRIMARY KEY, name TEXT NOT NULL, " +
+                "$childColumn REFERENCES departments(id) ON DELETE SET NULL)"
+        )
+        run("INSERT INTO departments VALUES (1, 'eng')")
+        run("INSERT INTO employees VALUES (1, 'ada', 1)")
+    }
+
+    @Test
+    fun insertRejectsForeignKeyViolation() {
+        val db = newDatabase()
+        db.seedDepartmentsAndEmployees()
+        val error = assertFailsWith<KestrelException> { db.run("INSERT INTO employees VALUES (1, 'ada', 99)") }
+        assertTrue(error.message!!.contains("FOREIGN KEY"))
+    }
+
+    @Test
+    fun insertAllowsNullForeignKeyValue() {
+        val db = newDatabase()
+        db.seedDepartmentsAndEmployees()
+        assertEquals(InsertResult(1), db.run("INSERT INTO employees VALUES (1, 'ada', NULL)").single())
+    }
+
+    @Test
+    fun insertSucceedsWhenReferencedRowExists() {
+        val db = newDatabase()
+        db.seedDepartmentsAndEmployees()
+        assertEquals(InsertResult(1), db.run("INSERT INTO employees VALUES (1, 'ada', 1)").single())
+    }
+
+    @Test
+    fun updateRejectsForeignKeyViolationOnChildColumn() {
+        val db = newDatabase()
+        db.seedDepartmentsAndEmployees()
+        db.run("INSERT INTO employees VALUES (1, 'ada', 1)")
+        assertFailsWith<KestrelException> { db.run("UPDATE employees SET dept_id = 99 WHERE id = 1") }
+    }
+