红宝石 - 遍历与SQL语句中找到记录

Question

我有一堆从employee_holiday_years这个SQL

选择id其中起始日期=“2015年1月1日”和EMPLOYEE_ID在（从员工选择ID找到的记录where join_date>'2014-12-31'）and allowance_from_last_year <> 0;

我需要使用Ruby遍历此SQL返回的记录，并针对每一个运行几个Ruby命令。这可能吗？

Answer 1

通过红宝石你可以试试这个让你有mysql适配器和ruby还安装你有

数据库名称TESTDB 用户名testuser 密码test123 主持人：localhost

require "dbi" 

    begin 
    dbh = DBI.connect("DBI:Mysql:TESTDB:localhost", 
        "testuser", "test123") 
    sth = dbh.prepare("select id from employee_holiday_years where start_date = '2015-01-01' and employee_id in(select id from employees where join_date > '2014-12-31') and allowance_from_last_year <> 0;") 
    sth.execute(1000) 

    #iterate through the return records 
    sth.fetch do |row| 
    printf row[0], row[1] #to print the row 

    end 
    sth.finish 

    rescue DBI::DatabaseError => e 
    puts "An error occurred" 
    puts "Error code: #{e.err}" 
    puts "Error message: #{e.errstr}" 
    ensure 
    # disconnect from server 
    dbh.disconnect if dbh 
    end 

更多Ruby Database Access

Answer 2

sql返回数组，所以使用数组迭代。

e.g

recoreds.each do |record| 
    p record.inspect 
end 

Answer 3

这是我想出了

client = Mysql2::Client.new(:host => "localhost", :username => "root", :database => "mydatabase") 
results = client.query("select * from mytable where...", :symbolise_keys => true) 

results.each do |row| 
    do stuff... 
end