Advanced Techniques in Go Programming/

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The Design and Implementation of the Go Package

The Design and Implementation of the Go Package

Let’s learn how to design and implement our Go package.

We'll cover the following...

The design of the Go package

The following diagram shows the database schema that the Go package works on. Remember that when working with a specific database and schema, we need to include the schema information in our Go code. Put simply, the Go code should know about the schema it works on:

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The two database tables the Go package works on
The two database tables the Go package works on

This is a simple schema that allows us to keep user data and update it. What connects the two tables is the user ID, which should be unique. Additionally, the Username field on the Users table should also be unique because two or more users can’t share the same username.

This schema already exists in the PostgreSQL database server, which means that the Go code assumes that the relevant tables are in the right place and are stored in the correct PostgreSQL database. Apart from the Users table, there is also a table named Userdata that holds information about each user. Once a record is entered in the Users table, it can’t be changed. What can change, however, is the data stored in the Userdata table.

We need to create two tables, Users and Userdata, to store information about our users. We can use the psql utility to execute the following statements, which are saved in a file named create_tables.sql, to create these tables in the go database:

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DROP DATABASE IF EXISTS go;
CREATE DATABASE go;
DROP TABLE IF EXISTS Users;
DROP TABLE IF EXISTS Userdata;
\c go;
CREATE TABLE Users (
    ID SERIAL,
    Username VARCHAR(100) PRIMARY KEY
);
CREATE TABLE Userdata (
    UserID Int NOT NULL,
    Name VARCHAR(100),
    Surname VARCHAR(100),
    Description VARCHAR(200)
);

The command-line utility for working with Postgres is called psql. The psql command for executing the code of create_tables.sql is as follows:

 psql -h localhost -p 5432 -U educative master < create_tables.sql

Now that we have the necessary infrastructure up and running, let’s begin discussing the Go package. The tasks that the Go package should perform to make our lives easier are as follows:

  • Create a new user

  • Delete an existing user

  • Update an existing user

  • List all users

Each of these tasks should have one or more Go functions or methods to support it, which is what we are going to implement in the Go package:

  • A ...