[feature] Added constraint support in migrations

lib/ecto/adapters/clickhouse/migration.ex

@@ -108,14 +108,37 @@ defmodule Ecto.Adapters.ClickHouse.Migration do
     [[drop | @conn.quote_table(index.prefix, index.name)]]
   end
 
-  def execute_ddl({command, %Constraint{} = _constraint})
+  def execute_ddl({command, %Constraint{} = constraint})
       when command in [:create, :create_if_not_exists] do
-    raise "TODO"
+    table_name = @conn.quote_table(constraint.prefix, constraint.table)
+
+    add =
+      case command do
+        :create -> " ADD CONSTRAINT "
+        :create_if_not_exists -> " ADD CONSTRAINT IF NOT EXISTS "
+      end
+
+    constraint_expr = constraint |> constraint_expr() |> Enum.join("")
+
+    [["ALTER TABLE ", table_name, add, constraint_expr]]
   end
 
-  def execute_ddl({command, %Constraint{} = _constraint, _mode})
+  def execute_ddl({command, %Constraint{} = constraint, _mode})
       when command in [:drop, :drop_if_exists] do
-    raise "TODO"
+    drop =
+      case command do
+        :drop -> " DROP CONSTRAINT "
+        :drop_if_exists -> " DROP CONSTRAINT IF EXISTS "
+      end
+
+    [
+      [
+        "ALTER TABLE ",
+        @conn.quote_table(constraint.prefix, constraint.table),
+        drop,
+        @conn.quote_name(constraint.name)
+      ]
+    ]
   end
 
   def execute_ddl({:rename, %Table{} = current_table, %Table{} = new_table}) do
@@ -305,6 +328,29 @@ defmodule Ecto.Adapters.ClickHouse.Migration do
   defp index_expr(literal) when is_binary(literal), do: literal
   defp index_expr(literal), do: @conn.quote_name(literal)
 
+  defp constraint_expr(%Constraint{check: check, validate: true, comment: nil} = constraint)
+       when is_binary(check) do
+    [
+      @conn.quote_name(constraint.name),
+      " CHECK (",
+      check,
+      ")"
+    ]
+  end
+
+  defp constraint_expr(%Constraint{check: check, validate: true, comment: comment})
+       when is_binary(check) and is_binary(comment) do
+    raise "Clickhouse adapter does not support comments on check constraints"
+  end
+
+  defp constraint_expr(%Constraint{check: check, validate: false}) when is_binary(check) do
+    raise "Clickhouse adapter does not support check constraints without validation on creation"
+  end
+
+  defp constraint_expr(%Constraint{exclude: exclude}) when is_binary(exclude) do
+    raise "Clickhouse adapter does not support exclude constraints"
+  end
+
   defp options_expr(nil), do: []
 
   defp options_expr(options) when is_list(options) do

test/ecto/adapters/clickhouse/connection_test.exs

@@ -2057,21 +2057,21 @@ defmodule Ecto.Adapters.ClickHouse.ConnectionTest do
     assert execute_ddl(drop) == [~s|DROP TABLE "foo"."posts"|]
   end
 
-  @tag skip: true
   test "drop constraint" do
     drop = {:drop, constraint(:products, "price_must_be_positive", prefix: :foo), :restrict}
 
     assert execute_ddl(drop) == [
-             ~s{DROP CONSTRAINT}
+             ~s|ALTER TABLE "foo"."products" DROP CONSTRAINT "price_must_be_positive"|
            ]
   end
 
-  @tag skip: true
   test "drop_if_exists constraint" do
     drop =
       {:drop_if_exists, constraint(:products, "price_must_be_positive", prefix: :foo), :restrict}
 
-    assert execute_ddl(drop) == []
+    assert execute_ddl(drop) == [
+             ~s|ALTER TABLE "foo"."products" DROP CONSTRAINT IF EXISTS "price_must_be_positive"|
+           ]
   end
 
   test "alter table" do
@@ -2355,16 +2355,6 @@ defmodule Ecto.Adapters.ClickHouse.ConnectionTest do
     assert execute_ddl(drop) == [~s|DROP INDEX "posts$main"|]
   end
 
-  @tag skip: true
-  test "create constraint" do
-    assert_raise ArgumentError,
-                 "ClickHouse does not support ALTER TABLE ADD CONSTRAINT",
-                 fn ->
-                   {:create, constraint(:products, "price_must_be_positive", check: "price > 0")}
-                   |> execute_ddl()
-                 end
-  end
-
   test "drop index with prefix" do
     drop = {:drop, index(:posts, [:id], name: "posts$main", prefix: :foo), :restrict}
     assert execute_ddl(drop) == [~s|DROP INDEX "foo"."posts$main"|]
@@ -2382,10 +2372,12 @@ defmodule Ecto.Adapters.ClickHouse.ConnectionTest do
     assert execute_ddl(drop) == [~s|DROP INDEX "posts$main"|]
   end
 
-  @tag skip: true
   test "create check constraint" do
     create = {:create, constraint(:products, "price_must_be_positive", check: "price > 0")}
-    assert execute_ddl(create) == []
+
+    assert execute_ddl(create) == [
+             ~s|ALTER TABLE "products" ADD CONSTRAINT "price_must_be_positive" CHECK (price > 0)|
+           ]
 
     create =
       {:create,
@@ -2394,7 +2386,18 @@ defmodule Ecto.Adapters.ClickHouse.ConnectionTest do
          prefix: "foo"
        )}
 
-    assert execute_ddl(create) == []
+    assert execute_ddl(create) == [
+             ~s|ALTER TABLE "foo"."products" ADD CONSTRAINT "price_must_be_positive" CHECK (price > 0)|
+           ]
+  end
+
+  test "create check constraint if not exists" do
+    create =
+      {:create_if_not_exists, constraint(:products, "price_must_be_positive", check: "price > 0")}
+
+    assert execute_ddl(create) == [
+             ~s|ALTER TABLE "products" ADD CONSTRAINT IF NOT EXISTS "price_must_be_positive" CHECK (price > 0)|
+           ]
   end
 
   @tag skip: true