Add support for CREATE SCHEMA

Author: Mehmet Emin KARAKAŞ (#136)

lib/pg_query/deparse.rb

@@ -108,6 +108,8 @@ def deparse_item(item, context = nil) # rubocop:disable Metrics/CyclomaticComple
         deparse_create_function(node)
       when CREATE_RANGE_STMT
         deparse_create_range(node)
+      when CREATE_SCHEMA_STMT
+        deparse_create_schema(node)
       when CREATE_STMT
         deparse_create_table(node)
       when CREATE_TABLE_AS_STMT
@@ -892,6 +894,15 @@ def deparse_create_range(node)
       output.join(' ')
     end
 
+    def deparse_create_schema(node)
+      output = ['CREATE SCHEMA']
+      output << 'IF NOT EXISTS' if node['if_not_exists']
+      output << deparse_identifier(node['schemaname']) if node.key?('schemaname')
+      output << format('AUTHORIZATION %s', deparse_item(node['authrole'])) if node.key?('authrole')
+      output << deparse_item_list(node['schemaElts']) if node.key?('schemaElts')
+      output.join(' ')
+    end
+
     def deparse_create_table(node)
       output = []
       output << 'CREATE'

spec/lib/pg_query/deparse_spec.rb

@@ -808,6 +808,40 @@
       end
     end
 
+    context 'CREATE SCHEMA' do
+      # Taken from https://www.postgresql.org/docs/11/sql-createschema.html
+      context 'basic' do
+        let(:query) { 'CREATE SCHEMA myschema' }
+
+        it { is_expected.to eq query }
+      end
+
+      context 'with authorization' do
+        let(:query) { 'CREATE SCHEMA AUTHORIZATION "joe"' }
+
+        it { is_expected.to eq query }
+      end
+
+      context 'with if not exist' do
+        let(:query) { 'CREATE SCHEMA IF NOT EXISTS test AUTHORIZATION "joe"' }
+
+        it { is_expected.to eq query }
+      end
+
+      context 'with cschema_element' do
+        let(:query) do
+          """
+          CREATE SCHEMA hollywood
+          CREATE TABLE \"films\" (title text, release date, awards text[])
+          CREATE VIEW winners AS
+              SELECT \"title\", \"release\" FROM \"films\" WHERE \"awards\" IS NOT NULL
+          """.strip
+        end
+
+        it { is_expected.to eq oneline_query }
+      end
+    end
+
     context 'CREATE TABLE' do
       context 'top-level' do
         let(:query) do