gorm: Setup initial project structure, schema, and db connection

Author: nvb

go/gorm/.gitignore

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+gorm

go/gorm/Makefile

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+# Copyright 2016 The Cockroach Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# permissions and limitations under the License. See the AUTHORS file
+# for names of contributors.
+#
+# Author: Nathan VanBenschoten ([email protected])
+
+.PHONY: start
+start:
+	@go build
+	@./gorm

go/gorm/main.go

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+package main
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/jinzhu/gorm"
+	_ "github.com/jinzhu/gorm/dialects/postgres"
+	"github.com/julienschmidt/httprouter"
+)
+
+func main() {
+	db := setupDB()
+	defer db.Close()
+
+	router := httprouter.New()
+
+	server := NewServer(db)
+	server.RegisterRouter(router)
+
+	log.Fatal(http.ListenAndServe(":8080", router))
+}
+
+func setupDB() *gorm.DB {
+	db, err := gorm.Open("postgres", "postgresql://root@localhost:26257/company_gorm?sslmode=disable")
+	if err != nil {
+		panic("failed to connect database")
+	}
+
+	// Migrate the schema
+	migrateDB(db)
+
+	// Initialize the database if it's empty.
+	var count int
+	db.Model(&Product{}).Count(&count)
+	if count == 0 {
+		// Create Products.
+		p1 := "P1"
+		p2 := "P2"
+		db.Create(&Product{Name: &p1, Price: 22.2})
+		db.Create(&Product{Name: &p2, Price: 2.2})
+
+		// Create Customers.
+		john := "John"
+		fred := "Fred"
+		db.Create(&Customer{Name: &john})
+		db.Create(&Customer{Name: &fred})
+
+		// Create an Order.
+		{
+			tx := db.Begin()
+
+			var product Product
+			tx.First(&product, "name = ?", "P2")
+
+			var customer Customer
+			tx.First(&customer, "name = ?", "Fred")
+
+			tx.Create(&Order{
+				Subtotal: product.Price,
+				Customer: customer,
+				Products: []Product{product},
+			})
+			tx.Commit()
+		}
+	}
+
+	return db
+}

go/gorm/models.go

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+package main
+
+import "github.com/jinzhu/gorm"
+
+// Customer is a model in the "customers" table.
+type Customer struct {
+	ID   int
+	Name *string `gorm:"not null"`
+}
+
+// Order is a model in the "orders" table.
+type Order struct {
+	ID       int
+	Subtotal float64 `gorm:"type:decimal(18,2)"`
+
+	Customer   Customer `gorm:"ForeignKey:CustomerID"`
+	CustomerID int      `json:"-"`
+
+	Products []Product `gorm:"many2many:order_products"`
+}
+
+// Product is a model in the "products" table.
+type Product struct {
+	ID    int
+	Name  *string `gorm:"not null;unique"`
+	Price float64 `gorm:"type:decimal(18,2)"`
+}
+
+func migrateDB(db *gorm.DB) {
+	db.AutoMigrate(&Customer{}, &Order{}, &Product{})
+}