module Sequel::Access::DatasetMethods

  1. lib/sequel/adapters/shared/access.rb

Constants

CAST_TYPES = {String=>:CStr, Integer=>:CLng, Date=>:CDate, Time=>:CDate, DateTime=>:CDate, Numeric=>:CDec, BigDecimal=>:CDec, File=>:CStr, Float=>:CDbl, TrueClass=>:CBool, FalseClass=>:CBool}.freeze  
EXTRACT_MAP = {:year=>"'yyyy'", :month=>"'m'", :day=>"'d'", :hour=>"'h'", :minute=>"'n'", :second=>"'s'"}.freeze  
OPS = {:'%'=>' Mod '.freeze, :'||'=>' & '.freeze}.freeze  

Public Instance methods

case_expression_sql_append(sql, ce)

Access doesn’t support CASE, so emulate it with nested IIF function calls.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
103 def case_expression_sql_append(sql, ce)
104   literal_append(sql, ce.with_merged_expression.conditions.reverse.inject(ce.default){|exp,(cond,val)| Sequel::SQL::Function.new(:IIF, cond, val, exp)})
105 end
cast_sql_append(sql, expr, type)

Access doesn’t support CAST, it uses separate functions for type conversion

[show source] 
    # File lib/sequel/adapters/shared/access.rb
109 def cast_sql_append(sql, expr, type)
110   sql << CAST_TYPES.fetch(type, type).to_s
111   sql << '('
112   literal_append(sql, expr)
113   sql << ')'
114 end
complex_expression_sql_append(sql, op, args)
[show source] 
    # File lib/sequel/adapters/shared/access.rb
116 def complex_expression_sql_append(sql, op, args)
117   case op
118   when :ILIKE
119     complex_expression_sql_append(sql, :LIKE, args)
120   when :'NOT ILIKE'
121     complex_expression_sql_append(sql, :'NOT LIKE', args)
122   when :'!='
123     sql << '('
124     literal_append(sql, args[0])
125     sql << ' <> '
126     literal_append(sql, args[1])
127     sql << ')'
128   when :'%', :'||'
129     sql << '('
130     c = false
131     op_str = OPS[op]
132     args.each do |a|
133       sql << op_str if c
134       literal_append(sql, a)
135       c ||= true
136     end
137     sql << ')'
138   when :**
139     sql << '('
140     literal_append(sql, args[0])
141     sql << ' ^ '
142     literal_append(sql, args[1])
143     sql << ')'
144   when :extract
145     part = args[0]
146     raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
147     sql << "datepart(" << format.to_s << ', '
148     literal_append(sql, args[1])
149     sql << ')'
150   else
151     super
152   end
153 end
constant_sql_append(sql, constant)

Use Date(), Now(), and Time() for CURRENT_DATE, CURRENT_TIMESTAMP, and CURRENT_TIME

[show source] 
    # File lib/sequel/adapters/shared/access.rb
156 def constant_sql_append(sql, constant)
157   case constant
158   when :CURRENT_DATE
159     sql << 'Date()'
160   when :CURRENT_TIMESTAMP
161     sql << 'Now()'
162   when :CURRENT_TIME
163     sql << 'Time()'
164   else
165     super
166   end
167 end
cross_join(table)

Emulate cross join by using multiple tables in the FROM clause.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
170 def cross_join(table)
171   clone(:from=>@opts[:from] + [table])
172 end
escape_like(string)

Access uses [] to escape metacharacters, instead of backslashes.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
175 def escape_like(string)
176   string.gsub(/[\\*#?\[]/){|m| "[#{m}]"}
177 end
into(table)

Specify a table for a SELECT … INTO query.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
180 def into(table)
181   clone(:into => table)
182 end
quoted_identifier_append(sql, v)

Access uses [] for quoting identifiers, and can’t handle ] inside identifiers.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
186 def quoted_identifier_append(sql, v)
187   sql << '[' << v.to_s << ']'
188 end
supports_derived_column_lists?()

Access does not support derived column lists.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
191 def supports_derived_column_lists?
192   false
193 end
supports_intersect_except?()

Access doesn’t support INTERSECT or EXCEPT

[show source] 
    # File lib/sequel/adapters/shared/access.rb
196 def supports_intersect_except?
197   false
198 end
supports_is_true?()

Access does not support IS TRUE

[show source] 
    # File lib/sequel/adapters/shared/access.rb
201 def supports_is_true?
202   false
203 end
supports_join_using?()

Access doesn’t support JOIN USING

[show source] 
    # File lib/sequel/adapters/shared/access.rb
206 def supports_join_using?
207   false
208 end
supports_multiple_column_in?()

Access does not support multiple columns for the IN/NOT IN operators

[show source] 
    # File lib/sequel/adapters/shared/access.rb
211 def supports_multiple_column_in?
212   false
213 end
truncate()

Access doesn’t support truncate, so do a delete instead.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
216 def truncate
217   delete
218   nil
219 end