Module Sequel::Access::DatasetMethods
In: lib/sequel/adapters/shared/access.rb

Methods

Included Modules

EmulateOffsetWithReverseAndCount

Constants

SELECT_CLAUSE_METHODS = Dataset.clause_methods(:select, %w'select distinct limit columns into from join where group order having compounds')
DATE_FORMAT = '#%Y-%m-%d#'.freeze
TIMESTAMP_FORMAT = '#%Y-%m-%d %H:%M:%S#'.freeze
TOP = " TOP ".freeze
BRACKET_CLOSE = Dataset::BRACKET_CLOSE
BRACKET_OPEN = Dataset::BRACKET_OPEN
PAREN_CLOSE = Dataset::PAREN_CLOSE
PAREN_OPEN = Dataset::PAREN_OPEN
INTO = Dataset::INTO
FROM = Dataset::FROM
SPACE = Dataset::SPACE
NOT_EQUAL = ' <> '.freeze
OPS = {:'%'=>' Mod '.freeze, :'||'=>' & '.freeze}
BOOL_FALSE = '0'.freeze
BOOL_TRUE = '-1'.freeze
DATE_FUNCTION = 'Date()'.freeze
NOW_FUNCTION = 'Now()'.freeze
TIME_FUNCTION = 'Time()'.freeze
CAST_TYPES = {String=>:CStr, Integer=>:CLng, Date=>:CDate, Time=>:CDate, DateTime=>:CDate, Numeric=>:CDec, BigDecimal=>:CDec, File=>:CStr, Float=>:CDbl, TrueClass=>:CBool, FalseClass=>:CBool}
EXTRACT_MAP = {:year=>"'yyyy'", :month=>"'m'", :day=>"'d'", :hour=>"'h'", :minute=>"'n'", :second=>"'s'"}
COMMA = Dataset::COMMA
DATEPART_OPEN = "datepart(".freeze

Public Instance methods

Access doesn‘t support CASE, but it can be emulated with nested IIF function calls.

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 119
119:       def case_expression_sql_append(sql, ce)
120:         literal_append(sql, ce.with_merged_expression.conditions.reverse.inject(ce.default){|exp,(cond,val)| Sequel::SQL::Function.new(:IIF, cond, val, exp)})
121:       end

Access doesn‘t support CAST, it uses separate functions for type conversion

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 125
125:       def cast_sql_append(sql, expr, type)
126:         sql << CAST_TYPES.fetch(type, type).to_s
127:         sql << PAREN_OPEN
128:         literal_append(sql, expr)
129:         sql << PAREN_CLOSE
130:       end

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 132
132:       def complex_expression_sql_append(sql, op, args)
133:         case op
134:         when :ILIKE
135:           complex_expression_sql_append(sql, :LIKE, args)
136:         when 'NOT ILIKE''NOT ILIKE'
137:           complex_expression_sql_append(sql, 'NOT LIKE''NOT LIKE', args)
138:         when :LIKE, 'NOT LIKE''NOT LIKE'
139:           sql << PAREN_OPEN
140:           literal_append(sql, args.at(0))
141:           sql << SPACE << op.to_s << SPACE
142:           literal_append(sql, args.at(1))
143:           sql << PAREN_CLOSE
144:         when '!=''!='
145:           sql << PAREN_OPEN
146:           literal_append(sql, args.at(0))
147:           sql << NOT_EQUAL
148:           literal_append(sql, args.at(1))
149:           sql << PAREN_CLOSE
150:         when '%''%', '||''||'
151:           sql << PAREN_OPEN
152:           c = false
153:           op_str = OPS[op]
154:           args.each do |a|
155:             sql << op_str if c
156:             literal_append(sql, a)
157:             c ||= true
158:           end
159:           sql << PAREN_CLOSE
160:         when :extract
161:           part = args.at(0)
162:           raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
163:           sql << DATEPART_OPEN << format.to_s << COMMA
164:           literal_append(sql, args.at(1))
165:           sql << PAREN_CLOSE
166:         else
167:           super
168:         end
169:       end

Use Date() and Now() for CURRENT_DATE and CURRENT_TIMESTAMP

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 172
172:       def constant_sql_append(sql, constant)
173:         case constant
174:         when :CURRENT_DATE
175:           sql << DATE_FUNCTION
176:         when :CURRENT_TIMESTAMP
177:           sql << NOW_FUNCTION
178:         when :CURRENT_TIME
179:           sql << TIME_FUNCTION
180:         else
181:           super
182:         end
183:       end

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

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 186
186:       def cross_join(table)
187:         clone(:from=>@opts[:from] + [table])
188:       end

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 190
190:       def emulated_function_sql_append(sql, f)
191:         case f.f
192:         when :char_length
193:           literal_append(sql, SQL::Function.new(:len, f.args.first))
194:         else
195:           super
196:         end
197:       end

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

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 200
200:       def escape_like(string)
201:         string.gsub(/[\\*#?\[]/){|m| "[#{m}]"}
202:       end

Specify a table for a SELECT … INTO query.

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 205
205:       def into(table)
206:         clone(:into => table)
207:       end

Access doesn‘t support INTERSECT or EXCEPT

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 210
210:       def supports_intersect_except?
211:         false
212:       end

Access does not support IS TRUE

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 215
215:       def supports_is_true?
216:         false
217:       end

Access doesn‘t support JOIN USING

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 220
220:       def supports_join_using?
221:         false
222:       end

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

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 225
225:       def supports_multiple_column_in?
226:         false
227:       end

Access doesn‘t support truncate, so do a delete instead.

[Source]

     # File lib/sequel/adapters/shared/access.rb, line 230
230:       def truncate
231:         delete
232:         nil
233:       end

[Validate]