Module: Sequel::Oracle::DatasetMethods

Included in:
JDBC::Oracle::Dataset, Dataset
Defined in:
lib/sequel/adapters/shared/oracle.rb

Constant Summary collapse

ROW_NUMBER_EXPRESSION =
LiteralString.new('ROWNUM').freeze
BITAND_PROC =
lambda{|a, b| Sequel.lit(["CAST(BITAND(", ", ", ") AS INTEGER)"], a, b)}

Instance Method Summary collapse

Instance Method Details

#complex_expression_sql_append(sql, op, args) ⇒ Object


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# File 'lib/sequel/adapters/shared/oracle.rb', line 329

def complex_expression_sql_append(sql, op, args)
  case op
  when :&
    complex_expression_arg_pairs_append(sql, args, &BITAND_PROC)
  when :|
    complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.lit(["(", " - ", " + ", ")"], a, complex_expression_arg_pairs([a, b], &BITAND_PROC), b)}
  when :^
    complex_expression_arg_pairs_append(sql, args) do |*x|
      s1 = complex_expression_arg_pairs(x){|a, b| Sequel.lit(["(", " - ", " + ", ")"], a, complex_expression_arg_pairs([a, b], &BITAND_PROC), b)}
      s2 = complex_expression_arg_pairs(x, &BITAND_PROC)
      Sequel.lit(["(", " - ", ")"], s1, s2)
    end
  when :~, :'!~', :'~*', :'!~*'
    raise InvalidOperation, "Pattern matching via regular expressions is not supported in this Oracle version" unless supports_regexp?
    if op == :'!~' || op == :'!~*'
      sql << 'NOT '
    end
    sql << 'REGEXP_LIKE('
    literal_append(sql, args[0])
    sql << ','
    literal_append(sql, args[1])
    if op == :'~*' || op == :'!~*'
      sql << ", 'i'"
    end
    sql << ')'
  when :%, :<<, :>>, :'B~'
    complex_expression_emulate_append(sql, op, args)
  else
    super
  end
end

#constant_sql_append(sql, c) ⇒ Object

Oracle doesn't support CURRENT_TIME, as it doesn't have a type for storing just time values without a date, so use CURRENT_TIMESTAMP in its place.


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# File 'lib/sequel/adapters/shared/oracle.rb', line 364

def constant_sql_append(sql, c)
  if c == :CURRENT_TIME
    super(sql, :CURRENT_TIMESTAMP)
  else
    super
  end
end

#empty?Boolean

Use a custom expression with EXISTS to determine whether a dataset is empty.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 380

def empty?
  db[:dual].where(@opts[:offset] ? exists : unordered.exists).get(1) == nil
end

#except(dataset, opts = OPTS) ⇒ Object

Oracle uses MINUS instead of EXCEPT, and doesn't support EXCEPT ALL

Raises:


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# File 'lib/sequel/adapters/shared/oracle.rb', line 373

def except(dataset, opts=OPTS)
  raise(Sequel::Error, "EXCEPT ALL not supported") if opts[:all]
  compound_clone(:minus, dataset, opts)
end

#recursive_cte_requires_column_aliases?Boolean

Oracle requires recursive CTEs to have column aliases.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 432

def recursive_cte_requires_column_aliases?
  true
end

#requires_sql_standard_datetimes?Boolean

Oracle requires SQL standard datetimes

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 385

def requires_sql_standard_datetimes?
  true
end

#select_sqlObject

Handle LIMIT by using a unlimited subselect filtered with ROWNUM, unless Oracle 12 is used.


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# File 'lib/sequel/adapters/shared/oracle.rb', line 398

def select_sql
  return super if @opts[:sql]
  return super if supports_fetch_next_rows?

  o = @opts[:offset]
  if o && o != 0
    columns = clone(:append_sql=>String.new, :placeholder_literal_null=>true).columns
    dsa1 = dataset_alias(1)
    rn = row_number_column
    limit = @opts[:limit]
    ds = unlimited.
      from_self(:alias=>dsa1).
      select_append(ROW_NUMBER_EXPRESSION.as(rn)).
      from_self(:alias=>dsa1).
      select(*columns).
      where(SQL::Identifier.new(rn) > o)
    ds = ds.where(SQL::Identifier.new(rn) <= Sequel.+(o, limit)) if limit
    sql = @opts[:append_sql] || String.new
    subselect_sql_append(sql, ds)
    sql
  elsif limit = @opts[:limit]
    ds = unlimited
    # Lock doesn't work in subselects, so don't use a subselect when locking.
    # Don't use a subselect if custom SQL is used, as it breaks somethings.
    ds = ds.from_self unless @opts[:lock]
    sql = @opts[:append_sql] || String.new
    subselect_sql_append(sql, ds.where(SQL::ComplexExpression.new(:<=, ROW_NUMBER_EXPRESSION, limit)))
    sql
  else
    super
  end
end

#sequence(s) ⇒ Object

Create a copy of this dataset associated to the given sequence name, which will be used when calling insert to find the most recently inserted value for the sequence.


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# File 'lib/sequel/adapters/shared/oracle.rb', line 392

def sequence(s)
  clone(:sequence=>s)
end

#server_versionObject

The version of the database server


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# File 'lib/sequel/adapters/shared/oracle.rb', line 517

def server_version
  db.server_version(@opts[:server])
end

#supports_cte?(type = :select) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 436

def supports_cte?(type=:select)
  type == :select
end

#supports_derived_column_lists?Boolean

Oracle does not support derived column lists

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 441

def supports_derived_column_lists?
  false
end

#supports_fetch_next_rows?Boolean

Oracle supports FETCH NEXT ROWS since 12c, but it doesn't work when locking or when skipping locked rows.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 447

def supports_fetch_next_rows?
  server_version >= 12000000 && !(@opts[:lock] || @opts[:skip_locked])
end

#supports_group_cube?Boolean

Oracle supports GROUP BY CUBE

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 452

def supports_group_cube?
  true
end

#supports_group_rollup?Boolean

Oracle supports GROUP BY ROLLUP

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 457

def supports_group_rollup?
  true
end

#supports_grouping_sets?Boolean

Oracle supports GROUPING SETS

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 462

def supports_grouping_sets?
  true
end

#supports_intersect_except_all?Boolean

Oracle does not support INTERSECT ALL or EXCEPT ALL

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 467

def supports_intersect_except_all?
  false
end

#supports_is_true?Boolean

Oracle does not support IS TRUE.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 472

def supports_is_true?
  false
end

#supports_limits_in_correlated_subqueries?Boolean

Oracle does not support limits in correlated subqueries.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 477

def supports_limits_in_correlated_subqueries?
  false
end

#supports_nowait?Boolean

Oracle supports NOWAIT.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 482

def supports_nowait?
  true
end

#supports_offsets_in_correlated_subqueries?Boolean

Oracle does not support offsets in correlated subqueries.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 487

def supports_offsets_in_correlated_subqueries?
  false
end

#supports_regexp?Boolean

Oracle 10+ supports pattern matching via regular expressions

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 522

def supports_regexp?
  server_version >= 10010002
end

#supports_select_all_and_column?Boolean

Oracle does not support SELECT *, column

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 492

def supports_select_all_and_column?
  false
end

#supports_skip_locked?Boolean

Oracle supports SKIP LOCKED.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 497

def supports_skip_locked?
  true
end

#supports_timestamp_timezones?Boolean

Oracle supports timezones in literal timestamps.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 502

def supports_timestamp_timezones?
  true
end

#supports_where_true?Boolean

Oracle does not support WHERE 'Y' for WHERE TRUE.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 507

def supports_where_true?
  false
end

#supports_window_functions?Boolean

Oracle supports window functions

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/oracle.rb', line 512

def supports_window_functions?
  true
end