Module: Sequel::SQL::Builders

Included in:
Sequel
Defined in:
lib/sequel/sql.rb,
lib/sequel/extensions/pg_row.rb,
lib/sequel/extensions/pg_json.rb,
lib/sequel/extensions/pg_array.rb,
lib/sequel/extensions/pg_range.rb,
lib/sequel/extensions/pg_hstore.rb,
lib/sequel/extensions/pg_row_ops.rb,
lib/sequel/extensions/pg_array_ops.rb,
lib/sequel/extensions/pg_range_ops.rb,
lib/sequel/extensions/pg_hstore_ops.rb,
lib/sequel/extensions/date_arithmetic.rb

Overview

These methods are designed as replacements for the core extensions, so that Sequel is still easy to use if the core extensions are not enabled.

Instance Method Summary collapse

Instance Method Details

#as(exp, aliaz) ⇒ Object

Create an SQL::AliasedExpression for the given expression and alias.

Sequel.as(:column, :alias) # "column" AS "alias"



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# File 'lib/sequel/sql.rb', line 306

def as(exp, aliaz)
  SQL::AliasedExpression.new(exp, aliaz)
end

#asc(arg, opts = {}) ⇒ Object

Order the given argument ascending. Options:

:nulls

Set to :first to use NULLS FIRST (so NULL values are ordered before other values), or :last to use NULLS LAST (so NULL values are ordered after other values).

Sequel.asc(:a) # a ASC
Sequel.asc(:b, :nulls=>:last) # b ASC NULLS LAST



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# File 'lib/sequel/sql.rb', line 319

def asc(arg, opts={})
  SQL::OrderedExpression.new(arg, false, opts)
end

#blob(s) ⇒ Object

Return an SQL::Blob that holds the same data as this string. Blobs provide proper escaping of binary data. If given a blob, returns it directly.



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# File 'lib/sequel/sql.rb', line 326

def blob(s)
  if s.is_a?(SQL::Blob)
    s
  else
    SQL::Blob.new(s)
  end
end

#case(*args) ⇒ Object

Return an SQL::CaseExpression created with the given arguments.

Sequel.case([[{:a=>[2,3]}, 1]], 0) # SQL: CASE WHEN a IN (2, 3) THEN 1 ELSE 0 END
Sequel.case({:a=>1}, 0, :b) # SQL: CASE b WHEN a THEN 1 ELSE 0 END



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# File 'lib/sequel/sql.rb', line 338

def case(*args) # core_sql ignore
  SQL::CaseExpression.new(*args)
end

#cast(arg, sql_type) ⇒ Object

Cast the reciever to the given SQL type. You can specify a ruby class as a type, and it is handled similarly to using a database independent type in the schema methods.

Sequel.cast(:a, :integer) # CAST(a AS integer)
Sequel.cast(:a, String) # CAST(a AS varchar(255))



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# File 'lib/sequel/sql.rb', line 347

def cast(arg, sql_type)
  SQL::Cast.new(arg, sql_type)
end

#cast_numeric(arg, sql_type = nil) ⇒ Object

Cast the reciever to the given SQL type (or the database’s default Integer type if none given), and return the result as a NumericExpression, so you can use the bitwise operators on the result. 

Sequel.cast_numeric(:a) # CAST(a AS integer)
Sequel.cast_numeric(:a, Float) # CAST(a AS double precision)



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# File 'lib/sequel/sql.rb', line 357

def cast_numeric(arg, sql_type = nil)
  cast(arg, sql_type || Integer).sql_number
end

#cast_string(arg, sql_type = nil) ⇒ Object

Cast the reciever to the given SQL type (or the database’s default String type if none given), and return the result as a StringExpression, so you can use + directly on the result for SQL string concatenation.

Sequel.cast_string(:a) # CAST(a AS varchar(255))
Sequel.cast_string(:a, :text) # CAST(a AS text)



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# File 'lib/sequel/sql.rb', line 367

def cast_string(arg, sql_type = nil)
  cast(arg, sql_type || String).sql_string
end

#char_length(arg) ⇒ Object

Return an emulated function call for getting the number of characters in the argument:

Sequel.char_length(:a) # char_length(a) -- Most databases
Sequel.char_length(:a) # length(a) -- SQLite



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# File 'lib/sequel/sql.rb', line 376

def char_length(arg)
  SQL::EmulatedFunction.new(:char_length, arg)
end

#date_add(expr, interval) ⇒ Object

Return a DateAdd expression, adding an interval to the date/timestamp expr.



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# File 'lib/sequel/extensions/date_arithmetic.rb', line 31

def date_add(expr, interval)
  DateAdd.new(expr, interval)
end

#date_sub(expr, interval) ⇒ Object

Return a DateAdd expression, adding the negative of the interval to the date/timestamp expr.



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# File 'lib/sequel/extensions/date_arithmetic.rb', line 37

def date_sub(expr, interval)
  interval = if interval.is_a?(Hash)
    h = {}
    interval.each{|k,v| h[k] = -v unless v.nil?}
    h
  else
    -interval
  end
  DateAdd.new(expr, interval)
end

#delay(&block) ⇒ Object

Return a delayed evaluation that uses the passed block. This is used to delay evaluations of the code to runtime. For example, with the following code:

ds = DB[:table].where{column > Time.now}

The filter is fixed to the time that where was called. Unless you are only using the dataset once immediately after creating it, that’s probably not desired. If you just want to set it to the time when the query is sent to the database, you can wrap it in Sequel.delay:

ds = DB[:table].where{column > Sequel.delay{Time.now}}

Note that for dates and timestamps, you are probably better off using Sequel::CURRENT_DATE and Sequel::CURRENT_TIMESTAMP instead of this generic delayed evaluation facility.

Raises:



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# File 'lib/sequel/sql.rb', line 396

def delay(&block)
  raise(Error, "Sequel.delay requires a block") unless block
  SQL::DelayedEvaluation.new(block)
end

#desc(arg, opts = {}) ⇒ Object

Order the given argument descending. Options:

:nulls

Set to :first to use NULLS FIRST (so NULL values are ordered before other values), or :last to use NULLS LAST (so NULL values are ordered after other values).

Sequel.desc(:a) # b DESC
Sequel.desc(:b, :nulls=>:first) # b DESC NULLS FIRST



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# File 'lib/sequel/sql.rb', line 410

def desc(arg, opts={})
  SQL::OrderedExpression.new(arg, true, opts)
end

#expr(arg = (no_arg=true), &block) ⇒ Object

Wraps the given object in an appropriate Sequel wrapper. If the given object is already a Sequel object, return it directly. For condition specifiers (hashes and arrays of two pairs), true, and false, return a boolean expressions. For numeric objects, return a numeric expression. For strings, return a string expression. For procs or when the method is passed a block, evaluate it as a virtual row and wrap it appropriately. In all other cases, use a generic wrapper.

This method allows you to construct SQL expressions that are difficult to construct via other methods. For example:

Sequel.expr(1) - :a # SQL: (1 - a)



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# File 'lib/sequel/sql.rb', line 426

def expr(arg=(no_arg=true), &block)
  if block_given?
    if no_arg
      return expr(block)
    else
      raise Error, 'cannot provide both an argument and a block to Sequel.expr'
    end
  elsif no_arg
    raise Error, 'must provide either an argument or a block to Sequel.expr'
  end

  case arg
  when Symbol
    t, c, a = Sequel.split_symbol(arg)

    arg = if t
      SQL::QualifiedIdentifier.new(t, c)
    else
      SQL::Identifier.new(c)
    end

    if a
      arg = SQL::AliasedExpression.new(arg, a)
    end

    arg
  when SQL::Expression, LiteralString, SQL::Blob
    arg
  when Hash
    SQL::BooleanExpression.from_value_pairs(arg, :AND)
  when Array
    if condition_specifier?(arg)
      SQL::BooleanExpression.from_value_pairs(arg, :AND)
    else
      SQL::Wrapper.new(arg)
    end
  when Numeric
    SQL::NumericExpression.new(:NOOP, arg)
  when String
    SQL::StringExpression.new(:NOOP, arg)
  when TrueClass, FalseClass
    SQL::BooleanExpression.new(:NOOP, arg)
  when Proc
    expr(virtual_row(&arg))
  else
    SQL::Wrapper.new(arg)
  end
end

#extract(datetime_part, exp) ⇒ Object

Extract a datetime_part (e.g. year, month) from the given expression:

Sequel.extract(:year, :date) # extract(year FROM "date")



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# File 'lib/sequel/sql.rb', line 479

def extract(datetime_part, exp)
  SQL::NumericExpression.new(:extract, datetime_part, exp)
end

#function(name, *args) ⇒ Object

Returns a Sequel::SQL::Function with the function name and the given arguments.

Sequel.function(:now) # SQL: now()
Sequel.function(:substr, :a, 1) # SQL: substr(a, 1)



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# File 'lib/sequel/sql.rb', line 488

def function(name, *args)
  SQL::Function.new(name, *args)
end

#hstore(v) ⇒ Object

Return a Postgres::HStore proxy for the given hash.



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# File 'lib/sequel/extensions/pg_hstore.rb', line 307

def hstore(v)
  case v
  when Postgres::HStore
    v
  when Hash
    Postgres::HStore.new(v)
  else
    # May not be defined unless the pg_hstore_ops extension is used
    hstore_op(v)
  end
end

#hstore_op(v) ⇒ Object

Return the object wrapped in an Postgres::HStoreOp.



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# File 'lib/sequel/extensions/pg_hstore_ops.rb', line 271

def hstore_op(v)
  case v
  when Postgres::HStoreOp
    v
  else
    Postgres::HStoreOp.new(v)
  end
end

#identifier(name) ⇒ Object

Return the argument wrapped as an SQL::Identifier.

Sequel.identifier(:a__b) # "a__b"



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# File 'lib/sequel/sql.rb', line 495

def identifier(name)
  SQL::Identifier.new(name)
end

#ilike(*args) ⇒ Object

Create a BooleanExpression case insensitive (if the database supports it) pattern match of the receiver with the given patterns. See SQL::StringExpression.like.

Sequel.ilike(:a, 'A%') # "a" ILIKE 'A%'



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# File 'lib/sequel/sql.rb', line 532

def ilike(*args)
  SQL::StringExpression.like(*(args << {:case_insensitive=>true}))
end

#join(args, joiner = nil) ⇒ Object

Return a Sequel::SQL::StringExpression representing an SQL string made up of the concatenation of the given array’s elements. If an argument is passed, it is used in between each element of the array in the SQL concatenation.

Sequel.join([:a]) # SQL: a
Sequel.join([:a, :b]) # SQL: a || b
Sequel.join([:a, 'b']) # SQL: a || 'b'
Sequel.join(['a', :b], ' ') # SQL: 'a' || ' ' || b

Raises:



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# File 'lib/sequel/sql.rb', line 508

def join(args, joiner=nil)
  raise Error, 'argument to Sequel.join must be an array' unless args.is_a?(Array)
  if joiner
    args = args.zip([joiner]*args.length).flatten
    args.pop
  end

  return SQL::StringExpression.new(:NOOP, '') if args.empty?

  args = args.map do |a|
    case a
    when Symbol, ::Sequel::SQL::Expression, ::Sequel::LiteralString, TrueClass, FalseClass, NilClass
      a
    else
      a.to_s
    end
  end
  SQL::StringExpression.new(:'||', *args)
end

#like(*args) ⇒ Object

Create a SQL::BooleanExpression case sensitive (if the database supports it) pattern match of the receiver with the given patterns. See SQL::StringExpression.like.

Sequel.like(:a, 'A%') # "a" LIKE 'A%'



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# File 'lib/sequel/sql.rb', line 540

def like(*args)
  SQL::StringExpression.like(*args)
end

#lit(s, *args) ⇒ Object

Converts a string into a Sequel::LiteralString, in order to override string literalization, e.g.:

DB[:items].filter(:abc => 'def').sql #=>
  "SELECT * FROM items WHERE (abc = 'def')"

DB[:items].filter(:abc => Sequel.lit('def')).sql #=>
  "SELECT * FROM items WHERE (abc = def)"

You can also provide arguments, to create a Sequel::SQL::PlaceholderLiteralString:

DB[:items].select{|o| o.count(Sequel.lit('DISTINCT ?', :a))}.sql #=>
  "SELECT count(DISTINCT a) FROM items"



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# File 'lib/sequel/sql.rb', line 557

def lit(s, *args) # core_sql ignore
  if args.empty?
    if s.is_a?(LiteralString)
      s
    else
      LiteralString.new(s)
    end
  else
    SQL::PlaceholderLiteralString.new(s, args) 
  end
end

#negate(arg) ⇒ Object

Return a Sequel::SQL::BooleanExpression created from the condition specifier, matching none of the conditions.

Sequel.negate(:a=>true) # SQL: a IS NOT TRUE
Sequel.negate([[:a, true]]) # SQL: a IS NOT TRUE
Sequel.negate([[:a, 1], [:b, 2]]) # SQL: ((a != 1) AND (b != 2))



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# File 'lib/sequel/sql.rb', line 575

def negate(arg)
  if condition_specifier?(arg)
    SQL::BooleanExpression.from_value_pairs(arg, :AND, true)
  else
    raise Error, 'must pass a conditions specifier to Sequel.negate'
  end
end

#or(arg) ⇒ Object

Return a Sequel::SQL::BooleanExpression created from the condition specifier, matching any of the conditions.

Sequel.or(:a=>true) # SQL: a IS TRUE
Sequel.or([[:a, true]]) # SQL: a IS TRUE
Sequel.or([[:a, 1], [:b, 2]]) # SQL: ((a = 1) OR (b = 2))



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# File 'lib/sequel/sql.rb', line 589

def or(arg)
  if condition_specifier?(arg)
    SQL::BooleanExpression.from_value_pairs(arg, :OR, false)
  else
    raise Error, 'must pass a conditions specifier to Sequel.or'
  end
end

#pg_array(v, array_type = nil) ⇒ Object

Return a Postgres::PGArray proxy for the given array and database array type.



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# File 'lib/sequel/extensions/pg_array.rb', line 510

def pg_array(v, array_type=nil)
  case v
  when Postgres::PGArray
    if array_type.nil? || v.array_type == array_type
      v
    else
      Postgres::PGArray.new(v.to_a, array_type)
    end
  when Array
    Postgres::PGArray.new(v, array_type)
  else
    # May not be defined unless the pg_array_ops extension is used
    pg_array_op(v)
  end
end

#pg_array_op(v) ⇒ Object

Return the object wrapped in an Postgres::ArrayOp.



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# File 'lib/sequel/extensions/pg_array_ops.rb', line 241

def pg_array_op(v)
  case v
  when Postgres::ArrayOp
    v
  else
    Postgres::ArrayOp.new(v)
  end
end

#pg_json(v) ⇒ Object

Wrap the array or hash in a Postgres::JSONArray or Postgres::JSONHash.



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# File 'lib/sequel/extensions/pg_json.rb', line 178

def pg_json(v)
  case v
  when Postgres::JSONArray, Postgres::JSONHash
    v
  when Array
    Postgres::JSONArray.new(v)
  when Hash
    Postgres::JSONHash.new(v)
  else
    raise Error, "Sequel.pg_json requires a hash or array argument"
  end
end

#pg_range(v, db_type = nil) ⇒ Object

Convert the object to a Postgres::PGRange.



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# File 'lib/sequel/extensions/pg_range.rb', line 486

def pg_range(v, db_type=nil)
  case v
  when Postgres::PGRange
    if db_type.nil? || v.db_type == db_type
      v
    else
      Postgres::PGRange.new(v.begin, v.end, :exclude_begin=>v.exclude_begin?, :exclude_end=>v.exclude_end?, :db_type=>db_type)
    end
  when Range
    Postgres::PGRange.from_range(v, db_type)
  else
    # May not be defined unless the pg_range_ops extension is used
    pg_range_op(v)
  end
end

#pg_range_op(v) ⇒ Object

Return the expression wrapped in the Postgres::RangeOp.



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# File 'lib/sequel/extensions/pg_range_ops.rb', line 128

def pg_range_op(v)
  case v
  when Postgres::RangeOp
    v
  else
    Postgres::RangeOp.new(v)
  end
end

#pg_row(expr) ⇒ Object

Wraps the expr array in an anonymous Postgres::PGRow::ArrayRow instance.



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# File 'lib/sequel/extensions/pg_row.rb', line 561

def pg_row(expr)
  case expr
  when Array
    Postgres::PGRow::ArrayRow.new(expr)
  else
    # Will only work if pg_row_ops extension is loaded
    pg_row_op(expr)
  end
end

#pg_row_op(expr) ⇒ Object

Return a PGRowOp wrapping the given expression.



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# File 'lib/sequel/extensions/pg_row_ops.rb', line 165

def pg_row_op(expr)
  Postgres::PGRowOp.wrap(expr)
end

#qualify(qualifier, identifier) ⇒ Object

Create a qualified identifier with the given qualifier and identifier

Sequel.qualify(:table, :column) # "table"."column"
Sequel.qualify(:schema, :table) # "schema"."table"
Sequel.qualify(:table, :column).qualify(:schema) # "schema"."table"."column"



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# File 'lib/sequel/sql.rb', line 602

def qualify(qualifier, identifier)
  SQL::QualifiedIdentifier.new(qualifier, identifier)
end

#subscript(exp, *subs) ⇒ Object

Return an SQL::Subscript with the given arguments, representing an SQL array access.

Sequel.subscript(:array, 1) # array[1]
Sequel.subscript(:array, 1, 2) # array[1, 2]
Sequel.subscript(:array, [1, 2]) # array[1, 2]



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# File 'lib/sequel/sql.rb', line 612

def subscript(exp, *subs)
  SQL::Subscript.new(exp, subs.flatten)
end

#trim(arg) ⇒ Object

Return an emulated function call for trimming a string of spaces from both sides (similar to ruby’s String#strip).

Sequel.trim(:a) # trim(a) -- Most databases
Sequel.trim(:a) # ltrim(rtrim(a)) -- Microsoft SQL Server



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# File 'lib/sequel/sql.rb', line 621

def trim(arg)
  SQL::EmulatedFunction.new(:trim, arg)
end

#value_list(arg) ⇒ Object

Return a SQL::ValueList created from the given array. Used if the array contains all two element arrays and you want it treated as an SQL value list (IN predicate) instead of as a conditions specifier (similar to a hash). This is not necessary if you are using this array as a value in a filter, but may be necessary if you are using it as a value with placeholder SQL:

DB[:a].filter([:a, :b]=>[[1, 2], [3, 4]]) # SQL: (a, b) IN ((1, 2), (3, 4))
DB[:a].filter('(a, b) IN ?', [[1, 2], [3, 4]]) # SQL: (a, b) IN ((1 = 2) AND (3 = 4))
DB[:a].filter('(a, b) IN ?', Sequel.value_list([[1, 2], [3, 4]])) # SQL: (a, b) IN ((1, 2), (3, 4))

Raises:



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# File 'lib/sequel/sql.rb', line 634

def value_list(arg)
  raise Error, 'argument to Sequel.value_list must be an array' unless arg.is_a?(Array)
  SQL::ValueList.new(arg)
end