Bulk import

.gitignore

@@ -4,6 +4,7 @@
 /.crystal/
 /doc/
 /config/*.db
+/.idea/
 
 # Libraries don't need dependency lock
 # Dependencies will be locked in application that uses them

src/adapter/base.cr

@@ -49,6 +49,9 @@ abstract class Granite::Adapter::Base
   # This will insert a row in the database and return the id generated.
   abstract def insert(table_name, fields, params, lastval) : Int64
 
+  # This will insert an array of models as one insert statement
+  abstract def import(table_name, primary_name, primary_auto, fields, model_array)
+
   # This will update a row in the database.
   abstract def update(table_name, primary_name, fields, params)
 

src/adapter/mysql.cr

@@ -76,6 +76,31 @@ class Granite::Adapter::Mysql < Granite::Adapter::Base
     end
   end
 
+  def import(table_name, primary_name, primary_auto, fields, model_array)
+  statement = String.build do |stmt|
+    stmt << "INSERT INTO #{quote(table_name)} ("
+    stmt << "#{quote(primary_name)}, " unless primary_auto
+    stmt << fields.map { |field| quote(field) }.join(", ")
+    stmt << ") VALUES "
+
+    model_array.each do |model|
+      if model.responds_to? :to_h
+        next unless model.valid?
+        stmt << "("
+        stmt << model.to_h[primary_name].to_s + ", " unless primary_auto
+        stmt << fields.map { |field| model.to_h[field].is_a?(String) ? "'" + model.to_h[field].to_s + "'" : model.to_h[field] }.join(", ")
+        stmt << "),"
+      end
+    end
+  end.chomp(",")
+
+    log statement
+
+    open do |db|
+      db.exec statement
+    end
+  end
+
   private def last_val
     return "SELECT LAST_INSERT_ID()"
   end

src/granite_orm/transactions.cr

@@ -7,9 +7,21 @@ module Granite::ORM::Transactions
     @updated_at : Time?
     @created_at : Time?
 
+    # The import class method will run a batch INSERT statement for each model in the array
+    # the array must contain only one model class
+    # invalid model records will be skipped
+    def self.import(model_array)
+      raise ArgumentError.new("Model class mismatch:  expected array of only #{self} models.") unless model_array.all? { |model| model.class == self }
+      begin
+       @@adapter.import(table_name, primary_name, {{primary_auto}}, fields, model_array)
+      rescue err
+        raise DB::Error.new(err.message)
+      end
+    end
+
     # The save method will check to see if the primary exists yet. If it does it
     # will call the update method, otherwise it will call the create method.
-    # This will update the timestamps apropriately.
+    # This will update the timestamps appropriately.
     def save
       return false unless valid?