class Sequel::JDBC::Derby::Dataset

Dataset class for Derby datasets accessed via JDBC.

Constants

BLOB_CLOSE
BLOB_OPEN
BOOL_FALSE
BOOL_FALSE_OLD
BOOL_TRUE
BOOL_TRUE_OLD
CAST_STRING_OPEN
DEFAULT_FROM
EMULATED_FUNCTION_MAP
FETCH_FIRST
HSTAR
OFFSET
PAREN_CLOSE
PAREN_OPEN
ROWS
ROWS_ONLY
TIME_FORMAT

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.

# File lib/sequel/adapters/jdbc/derby.rb, line 214
def case_expression_sql_append(sql, ce)
  super(sql, ce.with_merged_expression)
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, line 221
def cast_sql_append(sql, expr, type)
  if type == String
    sql << CAST_STRING_OPEN
    super
    sql << PAREN_CLOSE
  else
    super
  end
end
complex_expression_sql_append(sql, op, args) click to toggle source
# File lib/sequel/adapters/jdbc/derby.rb, line 231
def complex_expression_sql_append(sql, op, args)
  case op
  when :%, :'B~'
    complex_expression_emulate_append(sql, op, args)
  when :&, :|, :^, :<<, :>>
    raise Error, "Derby doesn't support the #{op} operator"
  when :**
    sql << 'exp('
    literal_append(sql, args[1])
    sql << ' * ln('
    literal_append(sql, args[0])
    sql << "))"
  when :extract
    sql << args.at(0).to_s << PAREN_OPEN
    literal_append(sql, args.at(1))
    sql << PAREN_CLOSE
  else
    super
  end
end
supports_group_rollup?() click to toggle source

Derby supports GROUP BY ROLLUP (but not CUBE)

# File lib/sequel/adapters/jdbc/derby.rb, line 253
def supports_group_rollup?
  true
end
supports_is_true?() click to toggle source

Derby does not support IS TRUE.

# File lib/sequel/adapters/jdbc/derby.rb, line 258
def supports_is_true?
  false
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, line 263
def supports_multiple_column_in?
  false
end

Private Instance Methods

empty_from_sql() click to toggle source
# File lib/sequel/adapters/jdbc/derby.rb, line 269
def empty_from_sql
  DEFAULT_FROM
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, line 280
def insert_supports_empty_values?
  false
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, line 274
def literal_blob_append(sql, v)
  sql << BLOB_OPEN << v.unpack(HSTAR).first << BLOB_CLOSE
end
literal_false() click to toggle source

Derby uses an expression yielding false for false values. Newer versions can use the FALSE literal, but the latest gem version cannot.

# File lib/sequel/adapters/jdbc/derby.rb, line 286
def literal_false
  if db.svn_version >= 1040133
    BOOL_FALSE
  else
    BOOL_FALSE_OLD
  end
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, line 295
def literal_sqltime(v)
  v.strftime(TIME_FORMAT)
end
literal_true() click to toggle source

Derby uses an expression yielding true for true values. Newer versions can use the TRUE literal, but the latest gem version cannot.

# File lib/sequel/adapters/jdbc/derby.rb, line 301
def literal_true
  if db.svn_version >= 1040133
    BOOL_TRUE
  else
    BOOL_TRUE_OLD
  end
end
multi_insert_sql_strategy() click to toggle source

Derby supports multiple rows in INSERT.

# File lib/sequel/adapters/jdbc/derby.rb, line 310
def multi_insert_sql_strategy
  :values
end
select_limit_sql(sql) click to toggle source

Offset comes before limit in Derby

# File lib/sequel/adapters/jdbc/derby.rb, line 315
def select_limit_sql(sql)
  if o = @opts[:offset]
    sql << OFFSET
    literal_append(sql, o)
    sql << ROWS
  end
  if l = @opts[:limit]
    sql << FETCH_FIRST
    literal_append(sql, l)
    sql << ROWS_ONLY
  end
end