Class: MIDB::API::Dbengine

Inherits:
Object
  • Object
show all
Defined in:
lib/midb/dbengine_model.rb

Overview

This class handles engine-dependent database operations

Author:

  • unrar

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(cnf, db) ⇒ Dbengine

Constructor - initializes the attributes with the configuration from ServerController

Parameters:

  • cnf (Array<String>) —

    The configuration array.

  • db (String) —

    Database name.



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# File 'lib/midb/dbengine_model.rb', line 28

def initialize(cnf, db)
  @engine = cnf["dbengine"]
  @host = cnf["dbhost"]
  @port = cnf["dbport"]
  @uname = cnf["dbuser"]
  @pwd = cnf["dbpassword"]
  @db = db
end

Instance Attribute Details

#db ⇒ String

Returns Name of the database.

Returns:

  • (String) —

    Name of the database



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# File 'lib/midb/dbengine_model.rb', line 22

attr_accessor :engine, :host, :uname, :pwd, :port, :db

#engine ⇒ Symbol

Returns The database engine being used.

Returns:

  • (Symbol) —

    The database engine being used



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# File 'lib/midb/dbengine_model.rb', line 22

def engine
  @engine
end

#host ⇒ String

Returns Host name where the database is located.

Returns:

  • (String) —

    Host name where the database is located



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# File 'lib/midb/dbengine_model.rb', line 22

attr_accessor :engine, :host, :uname, :pwd, :port, :db

#port ⇒ Fixnum

Returns Port for the database.

Returns:

  • (Fixnum) —

    Port for the database



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# File 'lib/midb/dbengine_model.rb', line 22

attr_accessor :engine, :host, :uname, :pwd, :port, :db

#pwd ⇒ String

Returns Password for the database.

Returns:

  • (String) —

    Password for the database.



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# File 'lib/midb/dbengine_model.rb', line 22

attr_accessor :engine, :host, :uname, :pwd, :port, :db

#uname ⇒ String

Returns Username for the database.

Returns:

  • (String) —

    Username for the database



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# File 'lib/midb/dbengine_model.rb', line 22

attr_accessor :engine, :host, :uname, :pwd, :port, :db

Instance Method Details

#connect ⇒ SQLite3::Database, Mysql2::Client

Connect to the specified database

Returns:

  • (SQLite3::Database, Mysql2::Client) —

    A resource referencing to the database



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# File 'lib/midb/dbengine_model.rb', line 40

def connect()
  begin
    # Connect to an SQLite3 database
    if @engine == :sqlite3
      sq = SQLite3::Database.open("./db/#{@db}.db")
      sq.results_as_hash = true
      return sq
    # Connect to a MySQL database
    elsif @engine == :mysql
      return Mysql2::Client.new(:host => @host, :username => @uname, :password => @pwd, :database => @db)
    end
  rescue
    MIDB::Interface::Errors.exception(:database_error, $!)
    return false
  end
end

#extract(result, field) ⇒ String, Fixnum

Extract a field from a query, because different engines return different types (see #query)

Parameters:

  • result (Array, Hash) —

    The result of a query obtained via #query

  • field (String) —

    The name of the field to be extracted.

Returns:

  • (String, Fixnum) —

    The field extracted from a query



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# File 'lib/midb/dbengine_model.rb', line 82

def extract(result, field)
  if @engine == :sqlite3
    return result[0][field] || result[field]
  elsif @engine == :mysql
    result.each do |row|
      return row[field]
    end
  end
end

#length(result) ⇒ Fixnum

Returns the length of a result, because different engines return diferent types (see #query)

Parameters:

  • result (Array, Hash) —

    The result of a query obtained via #query

Returns:

  • (Fixnum) —

    Length of the result.



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# File 'lib/midb/dbengine_model.rb', line 97

def length(result)
  if @engine == :sqlite3
    return result.length
  elsif @engine == :mysql 
    return result.count
  end
end

#query(res, query) ⇒ Array, Hash

Perform a query to the database.

Parameters:

  • res (SQLite3::Database, Mysql2::Client) —

    An existing database resource.

  • query (String) —

    The SQL query to be ran.

Returns:

  • (Array, Hash) —

    Returns an array of hashes for SQLite3 or a hash for MySQL



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# File 'lib/midb/dbengine_model.rb', line 63

def query(res, query)
  begin
    if @engine == :sqlite3
      return res.execute(query)
    elsif @engine == :mysql
      return res.query(query)
    end
  rescue
    MIDB::Interface::Errors.exception(:query_error, $!)
    return false
  end
end