Adding in extension support (#356)

* Adding in extension support.

* Update src/avram/migrator/alter_extension_statement.cr

Co-Authored-By: Paul Smith <paulcsmith@users.noreply.github.com>

Co-authored-by: Paul Smith <paulcsmith@users.noreply.github.com>

spec/migrator/alter_extension_statement_spec.cr

@@ -0,0 +1,13 @@
+require "../spec_helper"
+
+describe Avram::Migrator::AlterExtensionStatement do
+  it "builds the proper SQL to update an extension" do
+    statement = Avram::Migrator::AlterExtensionStatement.new("uuid-ossp")
+    statement.build.should eq %{ALTER EXTENSION "uuid-ossp" UPDATE;}
+  end
+
+  it "updates to a specific version" do
+    statement = Avram::Migrator::AlterExtensionStatement.new("hstore", to: "2.0")
+    statement.build.should eq %{ALTER EXTENSION "hstore" UPDATE TO '2.0';}
+  end
+end

spec/migrator/create_extension_statement_spec.cr

@@ -0,0 +1,8 @@
+require "../spec_helper"
+
+describe Avram::Migrator::CreateExtensionStatement do
+  it "builds the proper SQL for creating an extension" do
+    statement = Avram::Migrator::CreateExtensionStatement.new("uuid-ossp")
+    statement.build.should eq %{CREATE EXTENSION IF NOT EXISTS "uuid-ossp";}
+  end
+end

spec/migrator/drop_extension_statement_spec.cr

@@ -0,0 +1,8 @@
+require "../spec_helper"
+
+describe Avram::Migrator::DropExtensionStatement do
+  it "builds the proper SQL for dropping an extension" do
+    statement = Avram::Migrator::DropExtensionStatement.new("uuid-ossp")
+    statement.build.should eq %{DROP EXTENSION IF EXISTS "uuid-ossp" CASCADE;}
+  end
+end

src/avram/migrator/alter_extension_statement.cr

@@ -0,0 +1,16 @@
+class Avram::Migrator::AlterExtensionStatement
+  def initialize(@name : String, @to : String? = nil)
+  end
+
+  def build
+    String.build do |sql|
+      sql << %{ALTER EXTENSION "#{@name}" UPDATE}
+      sql << to_version if @to
+      sql << ";"
+    end
+  end
+
+  def to_version
+    " TO '#{@to}'"
+  end
+end

src/avram/migrator/create_extension_statement.cr

@@ -0,0 +1,10 @@
+class Avram::Migrator::CreateExtensionStatement
+  def initialize(@name : String)
+  end
+
+  def build
+    <<-SQL
+    CREATE EXTENSION IF NOT EXISTS "#{@name}";
+    SQL
+  end
+end

src/avram/migrator/drop_extension_statement.cr

@@ -0,0 +1,10 @@
+class Avram::Migrator::DropExtensionStatement
+  def initialize(@name : String)
+  end
+
+  def build
+    <<-SQL
+    DROP EXTENSION IF EXISTS "#{@name}" CASCADE;
+    SQL
+  end
+end

src/avram/migrator/statement_helpers.cr

@@ -47,4 +47,16 @@ module Avram::Migrator::StatementHelpers
   def make_optional(table : Symbol, column : Symbol)
     prepared_statements << Avram::Migrator::ChangeNullStatement.new(table, column, required: false).build
   end
+
+  def enable_extension(name : String)
+    prepared_statements << Avram::Migrator::CreateExtensionStatement.new(name).build
+  end
+
+  def disable_extension(name : String)
+    prepared_statements << Avram::Migrator::DropExtensionStatement.new(name).build
+  end
+
+  def update_extension(name : String, to : String? = nil)
+    prepared_statements << Avram::Migrator::AlterExtensionStatement.new(name, to: to).build
+  end
 end