Class: Sequel::JDBC::AS400::Dataset

Inherits:
Dataset show all
Defined in:
lib/sequel/adapters/jdbc/as400.rb

Overview

Dataset class for AS400 datasets accessed via JDBC.

Constant Summary collapse

WILDCARD = 
Sequel::LiteralString.new('*').freeze

Constants inherited from Dataset

Dataset::ACTION_METHODS, Dataset::AND_SEPARATOR, Dataset::ARG_BLOCK_ERROR_MSG, Dataset::ARRAY_ACCESS_ERROR_MSG, Dataset::BOOL_FALSE, Dataset::BOOL_TRUE, Dataset::COLUMN_CHANGE_OPTS, Dataset::COLUMN_REF_RE1, Dataset::COLUMN_REF_RE2, Dataset::COLUMN_REF_RE3, Dataset::COMMA_SEPARATOR, Dataset::CONDITIONED_JOIN_TYPES, Dataset::COUNT_FROM_SELF_OPTS, Dataset::COUNT_OF_ALL_AS_COUNT, Dataset::DATASET_ALIAS_BASE_NAME, Dataset::DELETE_CLAUSE_METHODS, Dataset::FOR_UPDATE, Dataset::IMPORT_ERROR_MSG, Dataset::INSERT_CLAUSE_METHODS, Dataset::IS_LITERALS, Dataset::IS_OPERATORS, Dataset::JOIN_METHODS, Dataset::MUTATION_METHODS, Dataset::NON_SQL_OPTIONS, Dataset::NOTIMPL_MSG, Dataset::NULL, Dataset::N_ARITY_OPERATORS, Dataset::PREPARED_ARG_PLACEHOLDER, Dataset::QUALIFY_KEYS, Dataset::QUERY_METHODS, Dataset::QUESTION_MARK, Dataset::SELECT_CLAUSE_METHODS, Dataset::SQL_WITH, Dataset::STANDARD_TIMESTAMP_FORMAT, Dataset::TIMESTAMP_FORMAT, Dataset::TO_DOT_OPTIONS, Dataset::TWO_ARITY_OPERATORS, Dataset::UNCONDITIONED_JOIN_TYPES, Dataset::UPDATE_CLAUSE_METHODS, Dataset::WITH_SUPPORTED

Instance Attribute Summary

Attributes inherited from Dataset

#convert_types

Attributes inherited from Dataset

#db, #identifier_input_method, #identifier_output_method, #opts, #quote_identifiers, #row_proc

Instance Method Summary collapse

Methods inherited from Dataset

#fetch_rows, #initialize, #prepare

Methods inherited from Dataset

#<<, #==, #[], #[]=, #add_graph_aliases, #aliased_expression_sql, #all, #and, #array_sql, #as, #avg, #bind, #boolean_constant_sql, #call, #case_expression_sql, #cast_sql, clause_methods, #clone, #column_all_sql, #columns, #columns!, #complex_expression_sql, #constant_sql, #count, def_mutation_method, #def_mutation_method, #delete, #delete_sql, #distinct, #each, #each_page, #each_server, #empty?, #eql?, #except, #exclude, #exists, #fetch_rows, #filter, #first, #first_source, #first_source_alias, #first_source_table, #for_update, #from, #from_self, #function_sql, #get, #graph, #grep, #group, #group_and_count, #group_by, #hash, #having, #import, #initialize, #insert, #insert_multiple, #insert_sql, #inspect, #intersect, #interval, introspect_all_columns, #invert, #join, #join_clause_sql, #join_on_clause_sql, #join_table, #join_using_clause_sql, #last, #limit, #literal, #lock_style, #map, #max, #min, #multi_insert, #multi_insert_sql, #naked, #negative_boolean_constant_sql, #or, #order, #order_append, #order_by, #order_more, #order_prepend, #ordered_expression_sql, #paginate, #placeholder_literal_string_sql, #prepare, #print, #provides_accurate_rows_matched?, #qualified_identifier_sql, #qualify, #qualify_to, #qualify_to_first_source, #query, #quote_identifier, #quote_identifiers?, #quote_schema_table, #quoted_identifier, #range, #requires_sql_standard_datetimes?, #reverse, #reverse_order, #schema_and_table, #select, #select_all, #select_append, #select_hash, #select_map, #select_more, #select_order_map, #server, #set, #set_defaults, #set_graph_aliases, #set_overrides, #single_record, #single_value, #split_alias, #sql, #subscript_sql, #sum, #supports_cte?, #supports_distinct_on?, #supports_intersect_except?, #supports_intersect_except_all?, #supports_is_true?, #supports_join_using?, #supports_modifying_joins?, #supports_multiple_column_in?, #supports_timestamp_timezones?, #supports_timestamp_usecs?, #to_csv, #to_dot, #to_hash, #truncate, #truncate_sql, #unfiltered, #ungraphed, #ungrouped, #union, #unlimited, #unordered, #unused_table_alias, #update, #update_sql, #where, #window_function_sql, #window_sql, #with, #with_recursive, #with_sql

Methods included from Metaprogramming

#meta_def

Constructor Details

This class inherits a constructor from Sequel::JDBC::Dataset

Instance Method Details

#select_limit_sql(sql) ⇒ Object

Modify the sql to limit the number of rows returned



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# File 'lib/sequel/adapters/jdbc/as400.rb', line 81

def select_limit_sql(sql)
  if @opts[:limit]
    sql << " FETCH FIRST ROW ONLY" if @opts[:limit] == 1
    sql << " FETCH FIRST #{@opts[:limit]} ROWS ONLY" if @opts[:limit] > 1
  end
end

#select_sql ⇒ Object

AS400 needs to use a couple of subselects for queries with offsets.



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# File 'lib/sequel/adapters/jdbc/as400.rb', line 63

def select_sql
  return super unless o = @opts[:offset]
  l = @opts[:limit]
  order = @opts[:order]
  dsa1 = dataset_alias(1)
  dsa2 = dataset_alias(2)
  rn = row_number_column
  irn = Sequel::SQL::Identifier.new(rn).qualify(dsa2)
  subselect_sql(unlimited.
      from_self(:alias=>dsa1).
      select_more(Sequel::SQL::QualifiedIdentifier.new(dsa1, WILDCARD),
      Sequel::SQL::WindowFunction.new(SQL::Function.new(:ROW_NUMBER), Sequel::SQL::Window.new(:order=>order)).as(rn)).
      from_self(:alias=>dsa2).
      select(Sequel::SQL::QualifiedIdentifier.new(dsa2, WILDCARD)).
      where(l ? ((irn > o) & (irn <= l + o)) : (irn > o))) # Leave off limit in case of limit(nil, offset)
end

#supports_window_functions? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/jdbc/as400.rb', line 88

def supports_window_functions?
  true
end