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
104 def case_expression_sql_append(sql, ce)
105   literal_append(sql, ce.with_merged_expression.conditions.reverse.inject(ce.default){|exp,(cond,val)| Sequel::SQL::Function.new(:IIF, cond, val, exp)})
106 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
110 def cast_sql_append(sql, expr, type)
111   sql << CAST_TYPES.fetch(type, type).to_s
112   sql << '('
113   literal_append(sql, expr)
114   sql << ')'
115 end
complex_expression_sql_append(sql, op, args)
[show source] 
    # File lib/sequel/adapters/shared/access.rb
117 def complex_expression_sql_append(sql, op, args)
118   case op
119   when :ILIKE
120     complex_expression_sql_append(sql, :LIKE, args)
121   when :'NOT ILIKE'
122     complex_expression_sql_append(sql, :'NOT LIKE', args)
123   when :'!='
124     sql << '('
125     literal_append(sql, args[0])
126     sql << ' <> '
127     literal_append(sql, args[1])
128     sql << ')'
129   when :'%', :'||'
130     sql << '('
131     c = false
132     op_str = OPS[op]
133     args.each do |a|
134       sql << op_str if c
135       literal_append(sql, a)
136       c ||= true
137     end
138     sql << ')'
139   when :**
140     sql << '('
141     literal_append(sql, args[0])
142     sql << ' ^ '
143     literal_append(sql, args[1])
144     sql << ')'
145   when :extract
146     part = args[0]
147     raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
148     sql << "datepart(" << format.to_s << ', '
149     literal_append(sql, args[1])
150     sql << ')'
151   else
152     super
153   end
154 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
157 def constant_sql_append(sql, constant)
158   case constant
159   when :CURRENT_DATE
160     sql << 'Date()'
161   when :CURRENT_TIMESTAMP
162     sql << 'Now()'
163   when :CURRENT_TIME
164     sql << 'Time()'
165   else
166     super
167   end
168 end
cross_join(table)

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

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

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

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

Specify a table for a SELECT … INTO query.

[show source] 
    # File lib/sequel/adapters/shared/access.rb
181 def into(table)
182   clone(:into => table)
183 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
187 def quoted_identifier_append(sql, v)
188   sql << '[' << v.to_s << ']'
189 end
supports_derived_column_lists?()

Access does not support derived column lists.

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

Access doesn’t support INTERSECT or EXCEPT

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

Access does not support IS TRUE

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

Access doesn’t support JOIN USING

[show source] 
    # File lib/sequel/adapters/shared/access.rb
207 def supports_join_using?
208   false
209 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
212 def supports_multiple_column_in?
213   false
214 end
truncate()

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

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