module Sequel::Access::DatasetMethods
Constants
- CAST_TYPES
- EXTRACT_MAP
- OPS
Public Instance Methods
Access
doesn't support CASE, so emulate it with nested IIF function calls.
# File lib/sequel/adapters/shared/access.rb 93 def case_expression_sql_append(sql, ce) 94 literal_append(sql, ce.with_merged_expression.conditions.reverse.inject(ce.default){|exp,(cond,val)| Sequel::SQL::Function.new(:IIF, cond, val, exp)}) 95 end
Access
doesn't support CAST, it uses separate functions for type conversion
# File lib/sequel/adapters/shared/access.rb 99 def cast_sql_append(sql, expr, type) 100 sql << CAST_TYPES.fetch(type, type).to_s 101 sql << '(' 102 literal_append(sql, expr) 103 sql << ')' 104 end
# File lib/sequel/adapters/shared/access.rb 106 def complex_expression_sql_append(sql, op, args) 107 case op 108 when :ILIKE 109 complex_expression_sql_append(sql, :LIKE, args) 110 when :'NOT ILIKE' 111 complex_expression_sql_append(sql, :'NOT LIKE', args) 112 when :'!=' 113 sql << '(' 114 literal_append(sql, args[0]) 115 sql << ' <> ' 116 literal_append(sql, args[1]) 117 sql << ')' 118 when :'%', :'||' 119 sql << '(' 120 c = false 121 op_str = OPS[op] 122 args.each do |a| 123 sql << op_str if c 124 literal_append(sql, a) 125 c ||= true 126 end 127 sql << ')' 128 when :** 129 sql << '(' 130 literal_append(sql, args[0]) 131 sql << ' ^ ' 132 literal_append(sql, args[1]) 133 sql << ')' 134 when :extract 135 part = args[0] 136 raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part] 137 sql << "datepart(" << format.to_s << ', ' 138 literal_append(sql, args[1]) 139 sql << ')' 140 else 141 super 142 end 143 end
Use Date(), Now(), and Time() for CURRENT_DATE, CURRENT_TIMESTAMP, and CURRENT_TIME
# File lib/sequel/adapters/shared/access.rb 146 def constant_sql_append(sql, constant) 147 case constant 148 when :CURRENT_DATE 149 sql << 'Date()' 150 when :CURRENT_TIMESTAMP 151 sql << 'Now()' 152 when :CURRENT_TIME 153 sql << 'Time()' 154 else 155 super 156 end 157 end
Emulate cross join by using multiple tables in the FROM clause.
# File lib/sequel/adapters/shared/access.rb 160 def cross_join(table) 161 clone(:from=>@opts[:from] + [table]) 162 end
Access
uses [] to escape metacharacters, instead of backslashes.
# File lib/sequel/adapters/shared/access.rb 165 def escape_like(string) 166 string.gsub(/[\\*#?\[]/){|m| "[#{m}]"} 167 end
Specify a table for a SELECT … INTO query.
# File lib/sequel/adapters/shared/access.rb 170 def into(table) 171 clone(:into => table) 172 end
Access
uses [] for quoting identifiers, and can't handle ] inside identifiers.
# File lib/sequel/adapters/shared/access.rb 176 def quoted_identifier_append(sql, v) 177 sql << '[' << v.to_s << ']' 178 end
Access
does not support derived column lists.
# File lib/sequel/adapters/shared/access.rb 181 def supports_derived_column_lists? 182 false 183 end
Access
doesn't support INTERSECT or EXCEPT
# File lib/sequel/adapters/shared/access.rb 186 def supports_intersect_except? 187 false 188 end
Access
does not support IS TRUE
# File lib/sequel/adapters/shared/access.rb 191 def supports_is_true? 192 false 193 end
Access
doesn't support JOIN USING
# File lib/sequel/adapters/shared/access.rb 196 def supports_join_using? 197 false 198 end
Access
does not support multiple columns for the IN/NOT IN operators
# File lib/sequel/adapters/shared/access.rb 201 def supports_multiple_column_in? 202 false 203 end
Access
doesn't support truncate, so do a delete instead.
# File lib/sequel/adapters/shared/access.rb 206 def truncate 207 delete 208 nil 209 end
Private Instance Methods
Access
uses # to quote dates
# File lib/sequel/adapters/shared/access.rb 214 def literal_date(d) 215 d.strftime('#%Y-%m-%d#') 216 end
Access
uses # to quote datetimes
# File lib/sequel/adapters/shared/access.rb 219 def literal_datetime(t) 220 t.strftime('#%Y-%m-%d %H:%M:%S#') 221 end
Use 0 for false on MSSQL
# File lib/sequel/adapters/shared/access.rb 225 def literal_false 226 '0' 227 end
Use -1 for true on MSSQL
# File lib/sequel/adapters/shared/access.rb 230 def literal_true 231 '-1' 232 end
Emulate the char_length function with len
# File lib/sequel/adapters/shared/access.rb 235 def native_function_name(emulated_function) 236 if emulated_function == :char_length 237 'len' 238 else 239 super 240 end 241 end
Access
does not natively support NULLS FIRST/LAST.
# File lib/sequel/adapters/shared/access.rb 244 def requires_emulating_nulls_first? 245 true 246 end
Access
doesn't support ESCAPE for LIKE.
# File lib/sequel/adapters/shared/access.rb 249 def requires_like_escape? 250 false 251 end
Access
requires parentheses when joining more than one table
# File lib/sequel/adapters/shared/access.rb 254 def select_from_sql(sql) 255 if f = @opts[:from] 256 sql << ' FROM ' 257 if (j = @opts[:join]) && !j.empty? 258 sql << ('(' * j.length) 259 end 260 source_list_append(sql, f) 261 end 262 end
# File lib/sequel/adapters/shared/access.rb 264 def select_into_sql(sql) 265 if i = @opts[:into] 266 sql << " INTO " 267 identifier_append(sql, i) 268 end 269 end
Access
requires parentheses when joining more than one table
# File lib/sequel/adapters/shared/access.rb 272 def select_join_sql(sql) 273 if js = @opts[:join] 274 js.each do |j| 275 literal_append(sql, j) 276 sql << ')' 277 end 278 end 279 end
Access
uses TOP for limits
# File lib/sequel/adapters/shared/access.rb 282 def select_limit_sql(sql) 283 if l = @opts[:limit] 284 sql << " TOP " 285 literal_append(sql, l) 286 end 287 end