ActiveRecord connection to seekdb sample program

This topic describes how to build an application using ActiveRecord and seekdb to perform basic operations such as creating tables, inserting data, and querying data.

Prerequisites

• You have installed Ruby and RubyGems.
• You have installed seekdb.

Procedure

1. Check the versions of Ruby and RubyGems.
2. Install the required gems.
3. Obtain the seekdb connection information.
4. Create and configure a Rails application.
5. Run the sample program.

Step 1: Check the versions of Ruby and RubyGems

Open the terminal and run the following command to check the versions of Ruby and RubyGems:

ruby -v
gem -v

Step 2: Install the required gems

1. Install the system dependencies (for example, Ubuntu):

   sudo apt-get install ruby-dev mysql-client libmysqlclient-dev

2. If you use RVM (Ruby Version Manager):

   rvm requirements

3. If you use rbenv:

   rbenv install -l  # View available versions
   rbenv install x.x.x  # Install a specific version
   rbenv global x.x.x  # Set the global version

4. Use gem to install ActiveRecord and mysql2:

   gem install activerecord mysql2

Step 3: Obtain the seekdb connection information

Contact the seekdb deployment personnel or administrator to obtain the database connection string.

mysql -h$host -P$port -u$user_name -p$password -D$database_name

Parameter description:

• $host: the IP address for connecting to seekdb.
• $port: the port for connecting to seekdb.
• $database_name: the name of the database to access.
• $user_name: the account for connecting to seekdb.
• $password: the password for the account.

Step 4: Create and configure a Rails application

1. Create a new Rails application:

   rails new activerecord_seekdb -d mysql

2. Configure the database connection information:

   Add the following configuration to config/database.yml:

   development:
     adapter: mysql2
     encoding: utf8mb4
     database: your_database
     username: your_username
     password: your_password
     host: your_host
     port: your_port

3. Create a sample model:

   # app/models/user.rb
   class User < ActiveRecord::Base
     validates :name, presence: true
   end

Step 5: Run the sample program

1. Create a database table:

   # db/migrate/20230520_create_users.rb
   class CreateUsers < ActiveRecord::Migration[6.1]
     def change
       create_table :users do |t|
         t.string :name
         t.timestamps
       end
     end
   end

2. Run the migration:

   rails db:migrate

3. Test in the Rails console:

   rails c

   # Create a record
   user = User.create(name: "John Doe")

   # Query records
   users = User.all

Common issues

1. Connection error: If you cannot connect to the database, check the following:

   • Whether the database address and port are correct
   • Whether the username and password are correct
   • Whether the network connection is normal

2. Permission error: If you encounter a permission-related error, make sure the user has sufficient permissions to perform the required operations.

3. SQL syntax error: If the SQL statement has a syntax error, check whether the SQL statement syntax is correct.

Performance optimization suggestions

1. Use ActiveRecord's batch operation methods (such as insert_all)
2. Use preloading (preload) to avoid N+1 query issues
3. Use caching appropriately
4. Optimize database indexes