require 'bigdecimal' require 'date' module Arel module Visitors class ToSql < Arel::Visitors::Visitor ## # This is some roflscale crazy stuff. I'm roflscaling this because # building SQL queries is a hotspot. I will explain the roflscale so that # others will not rm this code. # # In YARV, string literals in a method body will get duped when the byte # code is executed. Let's take a look: # # > puts RubyVM::InstructionSequence.new('def foo; "bar"; end').disasm # # == disasm: >===== # 0000 trace 8 # 0002 trace 1 # 0004 putstring "bar" # 0006 trace 16 # 0008 leave # # The `putstring` bytecode will dup the string and push it on the stack. # In many cases in our SQL visitor, that string is never mutated, so there # is no need to dup the literal. # # If we change to a constant lookup, the string will not be duped, and we # can reduce the objects in our system: # # > puts RubyVM::InstructionSequence.new('BAR = "bar"; def foo; BAR; end').disasm # # == disasm: >======== # 0000 trace 8 # 0002 trace 1 # 0004 getinlinecache 11, # 0007 getconstant :BAR # 0009 setinlinecache # 0011 trace 16 # 0013 leave # # `getconstant` should be a hash lookup, and no object is duped when the # value of the constant is pushed on the stack. Hence the crazy # constants below. # # `matches` and `doesNotMatch` operate case-insensitively via Visitor subclasses # specialized for specific databases when necessary. # WHERE = ' WHERE ' # :nodoc: SPACE = ' ' # :nodoc: COMMA = ', ' # :nodoc: GROUP_BY = ' GROUP BY ' # :nodoc: ORDER_BY = ' ORDER BY ' # :nodoc: WINDOW = ' WINDOW ' # :nodoc: AND = ' AND ' # :nodoc: DISTINCT = 'DISTINCT' # :nodoc: def initialize connection @connection = connection @schema_cache = connection.schema_cache @quoted_tables = {} @quoted_columns = {} end private def visit_Arel_Nodes_DeleteStatement o [ "DELETE FROM #{visit o.relation}", ("WHERE #{o.wheres.map { |x| visit x }.join AND}" unless o.wheres.empty?) ].compact.join ' ' end # FIXME: we should probably have a 2-pass visitor for this def build_subselect key, o stmt = Nodes::SelectStatement.new core = stmt.cores.first core.froms = o.relation core.wheres = o.wheres core.projections = [key] stmt.limit = o.limit stmt.orders = o.orders stmt end def visit_Arel_Nodes_UpdateStatement o if o.orders.empty? && o.limit.nil? wheres = o.wheres else wheres = [Nodes::In.new(o.key, [build_subselect(o.key, o)])] end [ "UPDATE #{visit o.relation}", ("SET #{o.values.map { |value| visit value }.join ', '}" unless o.values.empty?), ("WHERE #{wheres.map { |x| visit x }.join ' AND '}" unless wheres.empty?), ].compact.join ' ' end def visit_Arel_Nodes_InsertStatement o [ "INSERT INTO #{visit o.relation}", ("(#{o.columns.map { |x| quote_column_name x.name }.join ', '})" unless o.columns.empty?), (visit o.values if o.values), ].compact.join ' ' end def visit_Arel_Nodes_Exists o "EXISTS (#{visit o.expressions})#{ o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Casted o quoted o.val, o.attribute end def visit_Arel_Nodes_Quoted o quoted o.expr, nil end def visit_Arel_Nodes_True o "TRUE" end def visit_Arel_Nodes_False o "FALSE" end def table_exists? name @schema_cache.table_exists? name end def column_for attr return unless attr name = attr.name.to_s table = attr.relation.table_name return nil unless table_exists? table column_cache(table)[name] end def column_cache(table) @schema_cache.columns_hash(table) end def visit_Arel_Nodes_Values o "VALUES (#{o.expressions.zip(o.columns).map { |value, attr| if Nodes::SqlLiteral === value visit value else quote(value, attr && column_for(attr)) end }.join ', '})" end def visit_Arel_Nodes_SelectStatement o str = '' if o.with str << visit(o.with) str << SPACE end o.cores.each { |x| str << visit_Arel_Nodes_SelectCore(x) } unless o.orders.empty? str << SPACE str << ORDER_BY len = o.orders.length - 1 o.orders.each_with_index { |x, i| str << visit(x) str << COMMA unless len == i } end str << " #{visit(o.limit)}" if o.limit str << " #{visit(o.offset)}" if o.offset str << " #{visit(o.lock)}" if o.lock str.strip! str end def visit_Arel_Nodes_SelectCore o str = "SELECT" str << " #{visit(o.top)}" if o.top str << " #{visit(o.set_quantifier)}" if o.set_quantifier unless o.projections.empty? str << SPACE len = o.projections.length - 1 o.projections.each_with_index do |x, i| str << visit(x) str << COMMA unless len == i end end str << " FROM #{visit(o.source)}" if o.source && !o.source.empty? unless o.wheres.empty? str << WHERE len = o.wheres.length - 1 o.wheres.each_with_index do |x, i| str << visit(x) str << AND unless len == i end end unless o.groups.empty? str << GROUP_BY len = o.groups.length - 1 o.groups.each_with_index do |x, i| str << visit(x) str << COMMA unless len == i end end str << " #{visit(o.having)}" if o.having unless o.windows.empty? str << WINDOW len = o.windows.length - 1 o.windows.each_with_index do |x, i| str << visit(x) str << COMMA unless len == i end end str end def visit_Arel_Nodes_Bin o visit o.expr end def visit_Arel_Nodes_Distinct o DISTINCT end def visit_Arel_Nodes_DistinctOn o raise NotImplementedError, 'DISTINCT ON not implemented for this db' end def visit_Arel_Nodes_With o "WITH #{o.children.map { |x| visit x }.join(', ')}" end def visit_Arel_Nodes_WithRecursive o "WITH RECURSIVE #{o.children.map { |x| visit x }.join(', ')}" end def visit_Arel_Nodes_Union o "( #{visit o.left} UNION #{visit o.right} )" end def visit_Arel_Nodes_UnionAll o "( #{visit o.left} UNION ALL #{visit o.right} )" end def visit_Arel_Nodes_Intersect o "( #{visit o.left} INTERSECT #{visit o.right} )" end def visit_Arel_Nodes_Except o "( #{visit o.left} EXCEPT #{visit o.right} )" end def visit_Arel_Nodes_NamedWindow o "#{quote_column_name o.name} AS #{visit_Arel_Nodes_Window o}" end def visit_Arel_Nodes_Window o s = [ ("ORDER BY #{o.orders.map { |x| visit(x) }.join(', ')}" unless o.orders.empty?), (visit o.framing if o.framing) ].compact.join ' ' "(#{s})" end def visit_Arel_Nodes_Rows o if o.expr "ROWS #{visit o.expr}" else "ROWS" end end def visit_Arel_Nodes_Range o if o.expr "RANGE #{visit o.expr}" else "RANGE" end end def visit_Arel_Nodes_Preceding o "#{o.expr ? visit(o.expr) : 'UNBOUNDED'} PRECEDING" end def visit_Arel_Nodes_Following o "#{o.expr ? visit(o.expr) : 'UNBOUNDED'} FOLLOWING" end def visit_Arel_Nodes_CurrentRow o "CURRENT ROW" end def visit_Arel_Nodes_Over o case o.right when nil "#{visit o.left} OVER ()" when Arel::Nodes::SqlLiteral "#{visit o.left} OVER #{visit o.right}" when String, Symbol "#{visit o.left} OVER #{quote_column_name o.right.to_s}" else "#{visit o.left} OVER #{visit o.right}" end end def visit_Arel_Nodes_Having o "HAVING #{visit o.expr}" end def visit_Arel_Nodes_Offset o "OFFSET #{visit o.expr}" end def visit_Arel_Nodes_Limit o "LIMIT #{visit o.expr}" end # FIXME: this does nothing on most databases, but does on MSSQL def visit_Arel_Nodes_Top o "" end def visit_Arel_Nodes_Lock o visit o.expr end def visit_Arel_Nodes_Grouping o "(#{visit o.expr})" end def visit_Arel_SelectManager o "(#{o.to_sql.rstrip})" end def visit_Arel_Nodes_Ascending o "#{visit o.expr} ASC" end def visit_Arel_Nodes_Descending o "#{visit o.expr} DESC" end def visit_Arel_Nodes_Group o visit o.expr end def visit_Arel_Nodes_NamedFunction o "#{o.name}(#{o.distinct ? 'DISTINCT ' : ''}#{o.expressions.map { |x| visit x }.join(', ')})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Extract o "EXTRACT(#{o.field.to_s.upcase} FROM #{visit o.expr})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Count o "COUNT(#{o.distinct ? 'DISTINCT ' : ''}#{o.expressions.map { |x| visit x }.join(', ')})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Sum o "SUM(#{o.distinct ? 'DISTINCT ' : ''}#{o.expressions.map { |x| visit x}.join(', ')})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Max o "MAX(#{o.distinct ? 'DISTINCT ' : ''}#{o.expressions.map { |x| visit x}.join(', ')})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Min o "MIN(#{o.distinct ? 'DISTINCT ' : ''}#{o.expressions.map { |x| visit x }.join(', ')})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_Avg o "AVG(#{o.distinct ? 'DISTINCT ' : ''}#{o.expressions.map { |x| visit x }.join(', ')})#{o.alias ? " AS #{visit o.alias}" : ''}" end def visit_Arel_Nodes_TableAlias o "#{visit o.relation} #{quote_table_name o.name}" end def visit_Arel_Nodes_Between o "#{visit o.left} BETWEEN #{visit o.right}" end def visit_Arel_Nodes_GreaterThanOrEqual o "#{visit o.left} >= #{visit o.right}" end def visit_Arel_Nodes_GreaterThan o "#{visit o.left} > #{visit o.right}" end def visit_Arel_Nodes_LessThanOrEqual o "#{visit o.left} <= #{visit o.right}" end def visit_Arel_Nodes_LessThan o "#{visit o.left} < #{visit o.right}" end def visit_Arel_Nodes_Matches o "#{visit o.left} LIKE #{visit o.right}" end def visit_Arel_Nodes_DoesNotMatch o "#{visit o.left} NOT LIKE #{visit o.right}" end def visit_Arel_Nodes_JoinSource o [ (visit(o.left) if o.left), o.right.map { |j| visit j }.join(' ') ].compact.join ' ' end def visit_Arel_Nodes_StringJoin o visit o.left end def visit_Arel_Nodes_FullOuterJoin o "FULL OUTER JOIN #{visit o.left} #{visit o.right}" end def visit_Arel_Nodes_OuterJoin o "LEFT OUTER JOIN #{visit o.left} #{visit o.right}" end def visit_Arel_Nodes_RightOuterJoin o "RIGHT OUTER JOIN #{visit o.left} #{visit o.right}" end def visit_Arel_Nodes_InnerJoin o s = "INNER JOIN #{visit o.left}" if o.right s << SPACE s << visit(o.right) end s end def visit_Arel_Nodes_On o "ON #{visit o.expr}" end def visit_Arel_Nodes_Not o "NOT (#{visit o.expr})" end def visit_Arel_Table o if o.table_alias "#{quote_table_name o.name} #{quote_table_name o.table_alias}" else quote_table_name o.name end end def visit_Arel_Nodes_In o if Array === o.right && o.right.empty? '1=0' else "#{visit o.left} IN (#{visit o.right})" end end def visit_Arel_Nodes_NotIn o if Array === o.right && o.right.empty? '1=1' else "#{visit o.left} NOT IN (#{visit o.right})" end end def visit_Arel_Nodes_And o o.children.map { |x| visit x}.join ' AND ' end def visit_Arel_Nodes_Or o "#{visit o.left} OR #{visit o.right}" end def visit_Arel_Nodes_Assignment o case o.right when Arel::Nodes::UnqualifiedColumn, Arel::Attributes::Attribute "#{visit o.left} = #{visit o.right}" else right = quote(o.right, column_for(o.left)) "#{visit o.left} = #{right}" end end def visit_Arel_Nodes_Equality o right = o.right if right.nil? "#{visit o.left} IS NULL" else "#{visit o.left} = #{visit right}" end end def visit_Arel_Nodes_NotEqual o right = o.right if right.nil? "#{visit o.left} IS NOT NULL" else "#{visit o.left} != #{visit right}" end end def visit_Arel_Nodes_As o "#{visit o.left} AS #{visit o.right}" end def visit_Arel_Nodes_UnqualifiedColumn o "#{quote_column_name o.name}" end def visit_Arel_Attributes_Attribute o join_name = o.relation.table_alias || o.relation.name "#{quote_table_name join_name}.#{quote_column_name o.name}" end alias :visit_Arel_Attributes_Integer :visit_Arel_Attributes_Attribute alias :visit_Arel_Attributes_Float :visit_Arel_Attributes_Attribute alias :visit_Arel_Attributes_Decimal :visit_Arel_Attributes_Attribute alias :visit_Arel_Attributes_String :visit_Arel_Attributes_Attribute alias :visit_Arel_Attributes_Time :visit_Arel_Attributes_Attribute alias :visit_Arel_Attributes_Boolean :visit_Arel_Attributes_Attribute def literal o; o end alias :visit_Arel_Nodes_BindParam :literal alias :visit_Arel_Nodes_SqlLiteral :literal alias :visit_Bignum :literal alias :visit_Fixnum :literal def quoted o, a quote(o, column_for(a)) end def unsupported o, a raise "unsupported: #{o.class.name}" end alias :visit_ActiveSupport_Multibyte_Chars :unsupported alias :visit_ActiveSupport_StringInquirer :unsupported alias :visit_BigDecimal :unsupported alias :visit_Class :unsupported alias :visit_Date :unsupported alias :visit_DateTime :unsupported alias :visit_FalseClass :unsupported alias :visit_Float :unsupported alias :visit_Hash :unsupported alias :visit_NilClass :unsupported alias :visit_String :unsupported alias :visit_Symbol :unsupported alias :visit_Time :unsupported alias :visit_TrueClass :unsupported def visit_Arel_Nodes_InfixOperation o "#{visit o.left} #{o.operator} #{visit o.right}" end alias :visit_Arel_Nodes_Addition :visit_Arel_Nodes_InfixOperation alias :visit_Arel_Nodes_Subtraction :visit_Arel_Nodes_InfixOperation alias :visit_Arel_Nodes_Multiplication :visit_Arel_Nodes_InfixOperation alias :visit_Arel_Nodes_Division :visit_Arel_Nodes_InfixOperation def visit_Array o o.map { |x| visit x }.join(', ') end def quote value, column = nil return value if Arel::Nodes::SqlLiteral === value @connection.quote value, column end def quote_table_name name return name if Arel::Nodes::SqlLiteral === name @quoted_tables[name] ||= @connection.quote_table_name(name) end def quote_column_name name @quoted_columns[name] ||= Arel::Nodes::SqlLiteral === name ? name : @connection.quote_column_name(name) end end end end