Class: SqlStmtLib::MysqlBuilder

Inherits:
Object
  • Object
show all
Defined in:
lib/sqlstmt/mysql/build.rb

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ MysqlBuilder

Returns a new instance of MysqlBuilder.



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# File 'lib/sqlstmt/mysql/build.rb', line 5

def initialize(data)
  @data = data
end

Instance Method Details

#build_from_clause ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 50

def build_from_clause
  join_clause = build_join_clause
  group_clause = simple_clause('GROUP BY', @data.group_by)
  if @data.with_rollup
    group_clause += ' WITH ROLLUP'
  end
  order_clause = simple_clause('ORDER BY', @data.order_by)
  limit_clause = simple_clause('LIMIT', @data.limit)
  having_clause = @data.havings.empty? ? '' : " HAVING #{@data.havings.join(' AND ')}"
  return " FROM #{build_table_list}#{join_clause}#{build_where_clause}#{group_clause}#{having_clause}#{order_clause}#{limit_clause}"
end

#build_join_clause ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 89

def build_join_clause
  if @data.joins.empty?
    return ''
  else
    # we call uniq here to be tolerant of a table being joined to multiple times in an identical fashion
    # where the intention is not actually to include the table multiple times
    # but I'm thinking we may want to reconsider, or at least warn when this happens so the source bug can be fixed
    return ' ' + @data.joins.map {|join| join_to_str(join)}.uniq.join(' ')
  end
end

#build_set_clause ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 62

def build_set_clause
  set_exprs = []
  @data.set_fields.each_with_index do |field, index|
    set_exprs << "#{field} = #{@data.set_values[index]}"
  end
  return set_exprs.join(', ')
end

#build_stmt ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 9

def build_stmt
  method_name = "build_stmt_#{@data.stmt_type}"
  return send(method_name)
end

#build_stmt_delete ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 41

def build_stmt_delete
  if @data.tables_to_delete.empty?
    table_clause = ''
  else
    table_clause = ' ' + @data.tables_to_delete.join(',')
  end
  return "DELETE#{table_clause}#{build_from_clause}"
end

#build_stmt_insert ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 27

def build_stmt_insert
  keyword = @data.replace ? 'REPLACE' : 'INSERT'
  value_list = @data.set_values.join(',')
  ignore_str = @data.ignore ? 'IGNORE ' : ''
  start_str = "#{keyword} #{ignore_str}INTO #{@data.into} "
  if !@data.set_fields.empty?
    field_list = @data.set_fields.join(',')
    start_str += "(#{field_list}) "
  end

  distinct_str = @data.distinct ? 'DISTINCT ' : ''
  return "#{start_str}SELECT #{distinct_str}#{value_list}#{build_from_clause}"
end

#build_stmt_select ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 14

def build_stmt_select
  straight_join_str = @data.straight_join ? 'STRAIGHT_JOIN ' : ''
  distinct_str = @data.distinct ? 'DISTINCT ' : ''
  select_str = @data.gets.join(',')
  outfile_str = @data.outfile ? " INTO OUTFILE #{@data.outfile}" : ''
  return "SELECT #{straight_join_str}#{distinct_str}#{select_str}#{build_from_clause}#{outfile_str}"
end

#build_stmt_update ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 22

def build_stmt_update
  limit_clause = simple_clause('LIMIT', @data.limit)
  return "UPDATE #{build_table_list}#{build_join_clause} SET #{build_set_clause}#{build_where_clause}#{limit_clause}"
end

#build_table_list ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 77

def build_table_list
  return @data.tables.map {|table| table_to_str(table) }.join(',')
end

#build_where_clause ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 100

def build_where_clause
  return @data.wheres.empty? ? '' : " WHERE #{@data.wheres.join(' AND ')}"
end

#join_to_str(join) ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 85

def join_to_str(join)
  return [join.kwstr, join.table.str, join.on_expr].join(' ')
end

#simple_clause(keywords, value) ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 81

def simple_clause(keywords, value)
  return value ? " #{keywords} #{value}" : ''
end

#table_to_str(table) ⇒ Object 



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# File 'lib/sqlstmt/mysql/build.rb', line 70

def table_to_str(table)
  if table.index
    return "#{table.str} USE INDEX (#{table.index})"
  end
  return table.str
end