Class: Teebo::DatabaseHandler

Inherits:
Object
  • Object
show all
Defined in:
lib/teebo/database_handler.rb

Overview

This class facilitates the use of the database that accompanies this gem. Its primary goal is to simplify querying the database for required data, without having to write raw SQL statements throughout the codebase.

Author

Russ Taylor ([email protected])

Instance Method Summary collapse

Constructor Details

#initialize ⇒ DatabaseHandler

Returns a new instance of DatabaseHandler.



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# File 'lib/teebo/database_handler.rb', line 9

def initialize
  @database = SQLite3::Database.new 'lib/data/seed-data.db'
  @database.results_as_hash = true
end

Instance Method Details

#get_row_for_count(table_name, count_column, count_value, where_clause = nil) ⇒ Object

Retrieves the one row from the database where the specified number fits into this row’s ‘count_to’ range.



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# File 'lib/teebo/database_handler.rb', line 35

def get_row_for_count(table_name, count_column, count_value, where_clause=nil)
  where_statement = ''
  unless where_clause.nil?
    where_statement = "and #{where_clause[:column]} = '#{where_clause[:condition]}'"
  end
  statement = <<-SQL
    select * from #{table_name} where (#{count_column} - #{count_value}) >= 0
    #{where_statement}
    order by id limit 1
  SQL

  @database.execute(statement)[0]
end

#get_sum(table_name, column_name, where_clause = nil) ⇒ Object

Retrieves the sum of the specified column in the database. Optionally, a ‘where’ clause may be specified to restrict the sum to rows meeting a specified condition. Note that at present, only where clauses with one condition and an ‘=’ comparison are supported.



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# File 'lib/teebo/database_handler.rb', line 19

def get_sum(table_name, column_name, where_clause=nil)
  where_statement = ''
  unless where_clause.nil?
    where_statement = "where #{where_clause[:column]} = '#{where_clause[:condition]}'"
  end
  statement = <<-SQL
    select sum(#{column_name}) from #{table_name} #{where_statement}
  SQL

  @database.execute(statement)[0][0]
end