class Sequel::JDBC::Derby::Dataset

Public Instance Methods

case_expression_sql_append(sql, ce) click to toggle source

Derby doesn't support an expression between CASE and WHEN, so remove conditions.

Calls superclass method Sequel::Dataset#case_expression_sql_append

    # File lib/sequel/adapters/jdbc/derby.rb
192 def case_expression_sql_append(sql, ce)
193   super(sql, ce.with_merged_expression)
194 end

cast_sql_append(sql, expr, type) click to toggle source

If the type is String, trim the extra spaces since CHAR is used instead of varchar. This can cause problems if you are casting a char/varchar to a string and the ending whitespace is important.

Calls superclass method Sequel::Dataset#cast_sql_append

    # File lib/sequel/adapters/jdbc/derby.rb
199 def cast_sql_append(sql, expr, type)
200   if type == String
201     sql << "RTRIM("
202     super
203     sql << ')'
204   else
205     super
206   end
207 end

complex_expression_sql_append(sql, op, args) click to toggle source

Calls superclass method Sequel::Dataset#complex_expression_sql_append

    # File lib/sequel/adapters/jdbc/derby.rb
209 def complex_expression_sql_append(sql, op, args)
210   case op
211   when :%, :'B~'
212     complex_expression_emulate_append(sql, op, args)
213   when :&, :|, :^, :<<, :>>
214     raise Error, "Derby doesn't support the #{op} operator"
215   when :**
216     sql << 'exp('
217     literal_append(sql, args[1])
218     sql << ' * ln('
219     literal_append(sql, args[0])
220     sql << "))"
221   when :extract
222     sql << args[0].to_s << '('
223     literal_append(sql, args[1])
224     sql << ')'
225   else
226     super
227   end
228 end

supports_group_rollup?() click to toggle source

Derby supports GROUP BY ROLLUP (but not CUBE)

    # File lib/sequel/adapters/jdbc/derby.rb
231 def supports_group_rollup?
232   true
233 end

supports_is_true?() click to toggle source

Derby does not support IS TRUE.

    # File lib/sequel/adapters/jdbc/derby.rb
236 def supports_is_true?
237   false
238 end

supports_merge?() click to toggle source

Derby 10.11+ supports MERGE.

    # File lib/sequel/adapters/jdbc/derby.rb
241 def supports_merge?
242   db.svn_version >= 1616546
243 end

supports_multiple_column_in?() click to toggle source

Derby does not support IN/NOT IN with multiple columns

    # File lib/sequel/adapters/jdbc/derby.rb
246 def supports_multiple_column_in?
247   false
248 end

Private Instance Methods

empty_from_sql() click to toggle source

    # File lib/sequel/adapters/jdbc/derby.rb
252 def empty_from_sql
253   " FROM sysibm.sysdummy1"
254 end

insert_supports_empty_values?() click to toggle source

Derby needs the standard workaround to insert all default values into a table with more than one column.

    # File lib/sequel/adapters/jdbc/derby.rb
263 def insert_supports_empty_values?
264   false
265 end

literal_blob_append(sql, v) click to toggle source

Derby needs a hex string casted to BLOB for blobs.

    # File lib/sequel/adapters/jdbc/derby.rb
257 def literal_blob_append(sql, v)
258   sql << "CAST(X'" << v.unpack("H*").first << "' AS BLOB)"
259 end

literal_false() click to toggle source

Newer Derby versions can use the FALSE literal, but older versions need an always false expression.

    # File lib/sequel/adapters/jdbc/derby.rb
268 def literal_false
269   if db.svn_version >= 1040133
270     'FALSE'
271   else
272     '(1 = 0)'
273   end
274 end

literal_sqltime(v) click to toggle source

Derby handles fractional seconds in timestamps, but not in times

    # File lib/sequel/adapters/jdbc/derby.rb
277 def literal_sqltime(v)
278   v.strftime("'%H:%M:%S'")
279 end

literal_true() click to toggle source

Newer Derby versions can use the TRUE literal, but older versions need an always false expression.

    # File lib/sequel/adapters/jdbc/derby.rb
282 def literal_true
283   if db.svn_version >= 1040133
284     'TRUE'
285   else
286     '(1 = 1)'
287   end
288 end

multi_insert_sql_strategy() click to toggle source

Derby supports multiple rows for VALUES in INSERT.

    # File lib/sequel/adapters/jdbc/derby.rb
291 def multi_insert_sql_strategy
292   :values
293 end

native_function_name(emulated_function) click to toggle source

Emulate the char_length function with length

Calls superclass method Sequel::Dataset#native_function_name

    # File lib/sequel/adapters/jdbc/derby.rb
296 def native_function_name(emulated_function)
297   if emulated_function == :char_length
298     'length'
299   else
300     super
301   end
302 end

select_limit_sql(sql) click to toggle source

Offset comes before limit in Derby

    # File lib/sequel/adapters/jdbc/derby.rb
305 def select_limit_sql(sql)
306   if o = @opts[:offset]
307     sql << " OFFSET "
308     literal_append(sql, o)
309     sql << " ROWS"
310   end
311   if l = @opts[:limit]
312     sql << " FETCH FIRST "
313     literal_append(sql, l)
314     sql << " ROWS ONLY"
315   end
316 end