diff options
Diffstat (limited to 'activerecord/lib/arel/visitors/to_sql.rb')
| -rw-r--r-- | activerecord/lib/arel/visitors/to_sql.rb | 911 |
1 files changed, 911 insertions, 0 deletions
diff --git a/activerecord/lib/arel/visitors/to_sql.rb b/activerecord/lib/arel/visitors/to_sql.rb new file mode 100644 index 0000000000..f9fe4404eb --- /dev/null +++ b/activerecord/lib/arel/visitors/to_sql.rb @@ -0,0 +1,911 @@ +# frozen_string_literal: true + +module Arel # :nodoc: all + module Visitors + class UnsupportedVisitError < StandardError + def initialize(object) + super "Unsupported argument type: #{object.class.name}. Construct an Arel node instead." + end + end + + 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: <RubyVM::InstructionSequence:foo@<compiled>>===== + # 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: <RubyVM::InstructionSequence:foo@<compiled>>======== + # 0000 trace 8 + # 0002 trace 1 + # 0004 getinlinecache 11, <ic:0> + # 0007 getconstant :BAR + # 0009 setinlinecache <ic:0> + # 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) + super() + @connection = connection + end + + def compile(node, collector = Arel::Collectors::SQLString.new) + accept(node, collector).value + end + + private + + def visit_Arel_Nodes_DeleteStatement(o, collector) + o = prepare_delete_statement(o) + + if has_join_sources?(o) + collector << "DELETE " + visit o.relation.left, collector + collector << " FROM " + else + collector << "DELETE FROM " + end + collector = visit o.relation, collector + + collect_nodes_for o.wheres, collector, " WHERE ", " AND " + collect_nodes_for o.orders, collector, " ORDER BY " + maybe_visit o.limit, collector + end + + def visit_Arel_Nodes_UpdateStatement(o, collector) + o = prepare_update_statement(o) + + collector << "UPDATE " + collector = visit o.relation, collector + collect_nodes_for o.values, collector, " SET " + + collect_nodes_for o.wheres, collector, " WHERE ", " AND " + collect_nodes_for o.orders, collector, " ORDER BY " + maybe_visit o.limit, collector + end + + def visit_Arel_Nodes_InsertStatement(o, collector) + collector << "INSERT INTO " + collector = visit o.relation, collector + if o.columns.any? + collector << " (#{o.columns.map { |x| + quote_column_name x.name + }.join ', '})" + end + + if o.values + maybe_visit o.values, collector + elsif o.select + maybe_visit o.select, collector + else + collector + end + end + + def visit_Arel_Nodes_Exists(o, collector) + collector << "EXISTS (" + collector = visit(o.expressions, collector) << ")" + if o.alias + collector << " AS " + visit o.alias, collector + else + collector + end + end + + def visit_Arel_Nodes_Casted(o, collector) + collector << quoted(o.val, o.attribute).to_s + end + + def visit_Arel_Nodes_Quoted(o, collector) + collector << quoted(o.expr, nil).to_s + end + + def visit_Arel_Nodes_True(o, collector) + collector << "TRUE" + end + + def visit_Arel_Nodes_False(o, collector) + collector << "FALSE" + end + + def visit_Arel_Nodes_ValuesList(o, collector) + collector << "VALUES " + + len = o.rows.length - 1 + o.rows.each_with_index { |row, i| + collector << "(" + row_len = row.length - 1 + row.each_with_index do |value, k| + case value + when Nodes::SqlLiteral, Nodes::BindParam + collector = visit(value, collector) + else + collector << quote(value) + end + collector << COMMA unless k == row_len + end + collector << ")" + collector << COMMA unless i == len + } + collector + end + + def visit_Arel_Nodes_Values(o, collector) + collector << "VALUES (" + + len = o.expressions.length - 1 + o.expressions.each_with_index { |value, i| + case value + when Nodes::SqlLiteral, Nodes::BindParam + collector = visit value, collector + else + collector << quote(value).to_s + end + unless i == len + collector << COMMA + end + } + + collector << ")" + end + + def visit_Arel_Nodes_SelectStatement(o, collector) + if o.with + collector = visit o.with, collector + collector << SPACE + end + + collector = o.cores.inject(collector) { |c, x| + visit_Arel_Nodes_SelectCore(x, c) + } + + unless o.orders.empty? + collector << ORDER_BY + len = o.orders.length - 1 + o.orders.each_with_index { |x, i| + collector = visit(x, collector) + collector << COMMA unless len == i + } + end + + visit_Arel_Nodes_SelectOptions(o, collector) + + collector + end + + def visit_Arel_Nodes_SelectOptions(o, collector) + collector = maybe_visit o.limit, collector + collector = maybe_visit o.offset, collector + collector = maybe_visit o.lock, collector + end + + def visit_Arel_Nodes_SelectCore(o, collector) + collector << "SELECT" + + collector = maybe_visit o.set_quantifier, collector + + collect_nodes_for o.projections, collector, SPACE + + if o.source && !o.source.empty? + collector << " FROM " + collector = visit o.source, collector + end + + collect_nodes_for o.wheres, collector, WHERE, AND + collect_nodes_for o.groups, collector, GROUP_BY + collect_nodes_for o.havings, collector, " HAVING ", AND + collect_nodes_for o.windows, collector, WINDOW + + collector + end + + def collect_nodes_for(nodes, collector, spacer, connector = COMMA) + unless nodes.empty? + collector << spacer + inject_join nodes, collector, connector + end + end + + def visit_Arel_Nodes_Bin(o, collector) + visit o.expr, collector + end + + def visit_Arel_Nodes_Distinct(o, collector) + collector << DISTINCT + end + + def visit_Arel_Nodes_DistinctOn(o, collector) + raise NotImplementedError, "DISTINCT ON not implemented for this db" + end + + def visit_Arel_Nodes_With(o, collector) + collector << "WITH " + inject_join o.children, collector, COMMA + end + + def visit_Arel_Nodes_WithRecursive(o, collector) + collector << "WITH RECURSIVE " + inject_join o.children, collector, COMMA + end + + def visit_Arel_Nodes_Union(o, collector) + infix_value_with_paren(o, collector, " UNION ") + end + + def visit_Arel_Nodes_UnionAll(o, collector) + infix_value_with_paren(o, collector, " UNION ALL ") + end + + def visit_Arel_Nodes_Intersect(o, collector) + collector << "( " + infix_value(o, collector, " INTERSECT ") << " )" + end + + def visit_Arel_Nodes_Except(o, collector) + collector << "( " + infix_value(o, collector, " EXCEPT ") << " )" + end + + def visit_Arel_Nodes_NamedWindow(o, collector) + collector << quote_column_name(o.name) + collector << " AS " + visit_Arel_Nodes_Window o, collector + end + + def visit_Arel_Nodes_Window(o, collector) + collector << "(" + + collect_nodes_for o.partitions, collector, "PARTITION BY " + + if o.orders.any? + collector << SPACE if o.partitions.any? + collector << "ORDER BY " + collector = inject_join o.orders, collector, ", " + end + + if o.framing + collector << SPACE if o.partitions.any? || o.orders.any? + collector = visit o.framing, collector + end + + collector << ")" + end + + def visit_Arel_Nodes_Rows(o, collector) + if o.expr + collector << "ROWS " + visit o.expr, collector + else + collector << "ROWS" + end + end + + def visit_Arel_Nodes_Range(o, collector) + if o.expr + collector << "RANGE " + visit o.expr, collector + else + collector << "RANGE" + end + end + + def visit_Arel_Nodes_Preceding(o, collector) + collector = if o.expr + visit o.expr, collector + else + collector << "UNBOUNDED" + end + + collector << " PRECEDING" + end + + def visit_Arel_Nodes_Following(o, collector) + collector = if o.expr + visit o.expr, collector + else + collector << "UNBOUNDED" + end + + collector << " FOLLOWING" + end + + def visit_Arel_Nodes_CurrentRow(o, collector) + collector << "CURRENT ROW" + end + + def visit_Arel_Nodes_Over(o, collector) + case o.right + when nil + visit(o.left, collector) << " OVER ()" + when Arel::Nodes::SqlLiteral + infix_value o, collector, " OVER " + when String, Symbol + visit(o.left, collector) << " OVER #{quote_column_name o.right.to_s}" + else + infix_value o, collector, " OVER " + end + end + + def visit_Arel_Nodes_Offset(o, collector) + collector << "OFFSET " + visit o.expr, collector + end + + def visit_Arel_Nodes_Limit(o, collector) + collector << "LIMIT " + visit o.expr, collector + end + + def visit_Arel_Nodes_Lock(o, collector) + visit o.expr, collector + end + + def visit_Arel_Nodes_Grouping(o, collector) + if o.expr.is_a? Nodes::Grouping + visit(o.expr, collector) + else + collector << "(" + visit(o.expr, collector) << ")" + end + end + + def visit_Arel_SelectManager(o, collector) + collector << "(" + visit(o.ast, collector) << ")" + end + + def visit_Arel_Nodes_Ascending(o, collector) + visit(o.expr, collector) << " ASC" + end + + def visit_Arel_Nodes_Descending(o, collector) + visit(o.expr, collector) << " DESC" + end + + def visit_Arel_Nodes_Group(o, collector) + visit o.expr, collector + end + + def visit_Arel_Nodes_NamedFunction(o, collector) + collector << o.name + collector << "(" + collector << "DISTINCT " if o.distinct + collector = inject_join(o.expressions, collector, ", ") << ")" + if o.alias + collector << " AS " + visit o.alias, collector + else + collector + end + end + + def visit_Arel_Nodes_Extract(o, collector) + collector << "EXTRACT(#{o.field.to_s.upcase} FROM " + visit(o.expr, collector) << ")" + end + + def visit_Arel_Nodes_Count(o, collector) + aggregate "COUNT", o, collector + end + + def visit_Arel_Nodes_Sum(o, collector) + aggregate "SUM", o, collector + end + + def visit_Arel_Nodes_Max(o, collector) + aggregate "MAX", o, collector + end + + def visit_Arel_Nodes_Min(o, collector) + aggregate "MIN", o, collector + end + + def visit_Arel_Nodes_Avg(o, collector) + aggregate "AVG", o, collector + end + + def visit_Arel_Nodes_TableAlias(o, collector) + collector = visit o.relation, collector + collector << " " + collector << quote_table_name(o.name) + end + + def visit_Arel_Nodes_Between(o, collector) + collector = visit o.left, collector + collector << " BETWEEN " + visit o.right, collector + end + + def visit_Arel_Nodes_GreaterThanOrEqual(o, collector) + collector = visit o.left, collector + collector << " >= " + visit o.right, collector + end + + def visit_Arel_Nodes_GreaterThan(o, collector) + collector = visit o.left, collector + collector << " > " + visit o.right, collector + end + + def visit_Arel_Nodes_LessThanOrEqual(o, collector) + collector = visit o.left, collector + collector << " <= " + visit o.right, collector + end + + def visit_Arel_Nodes_LessThan(o, collector) + collector = visit o.left, collector + collector << " < " + visit o.right, collector + end + + def visit_Arel_Nodes_Matches(o, collector) + collector = visit o.left, collector + collector << " LIKE " + collector = visit o.right, collector + if o.escape + collector << " ESCAPE " + visit o.escape, collector + else + collector + end + end + + def visit_Arel_Nodes_DoesNotMatch(o, collector) + collector = visit o.left, collector + collector << " NOT LIKE " + collector = visit o.right, collector + if o.escape + collector << " ESCAPE " + visit o.escape, collector + else + collector + end + end + + def visit_Arel_Nodes_JoinSource(o, collector) + if o.left + collector = visit o.left, collector + end + if o.right.any? + collector << SPACE if o.left + collector = inject_join o.right, collector, SPACE + end + collector + end + + def visit_Arel_Nodes_Regexp(o, collector) + raise NotImplementedError, "~ not implemented for this db" + end + + def visit_Arel_Nodes_NotRegexp(o, collector) + raise NotImplementedError, "!~ not implemented for this db" + end + + def visit_Arel_Nodes_StringJoin(o, collector) + visit o.left, collector + end + + def visit_Arel_Nodes_FullOuterJoin(o, collector) + collector << "FULL OUTER JOIN " + collector = visit o.left, collector + collector << SPACE + visit o.right, collector + end + + def visit_Arel_Nodes_OuterJoin(o, collector) + collector << "LEFT OUTER JOIN " + collector = visit o.left, collector + collector << " " + visit o.right, collector + end + + def visit_Arel_Nodes_RightOuterJoin(o, collector) + collector << "RIGHT OUTER JOIN " + collector = visit o.left, collector + collector << SPACE + visit o.right, collector + end + + def visit_Arel_Nodes_InnerJoin(o, collector) + collector << "INNER JOIN " + collector = visit o.left, collector + if o.right + collector << SPACE + visit(o.right, collector) + else + collector + end + end + + def visit_Arel_Nodes_On(o, collector) + collector << "ON " + visit o.expr, collector + end + + def visit_Arel_Nodes_Not(o, collector) + collector << "NOT (" + visit(o.expr, collector) << ")" + end + + def visit_Arel_Table(o, collector) + if o.table_alias + collector << "#{quote_table_name o.name} #{quote_table_name o.table_alias}" + else + collector << quote_table_name(o.name) + end + end + + def visit_Arel_Nodes_In(o, collector) + if Array === o.right && !o.right.empty? + o.right.keep_if { |value| boundable?(value) } + end + + if Array === o.right && o.right.empty? + collector << "1=0" + else + collector = visit o.left, collector + collector << " IN (" + visit(o.right, collector) << ")" + end + end + + def visit_Arel_Nodes_NotIn(o, collector) + if Array === o.right && !o.right.empty? + o.right.keep_if { |value| boundable?(value) } + end + + if Array === o.right && o.right.empty? + collector << "1=1" + else + collector = visit o.left, collector + collector << " NOT IN (" + collector = visit o.right, collector + collector << ")" + end + end + + def visit_Arel_Nodes_And(o, collector) + inject_join o.children, collector, " AND " + end + + def visit_Arel_Nodes_Or(o, collector) + collector = visit o.left, collector + collector << " OR " + visit o.right, collector + end + + def visit_Arel_Nodes_Assignment(o, collector) + case o.right + when Arel::Nodes::Node, Arel::Attributes::Attribute + collector = visit o.left, collector + collector << " = " + visit o.right, collector + else + collector = visit o.left, collector + collector << " = " + collector << quote(o.right).to_s + end + end + + def visit_Arel_Nodes_Equality(o, collector) + right = o.right + + collector = visit o.left, collector + + if right.nil? + collector << " IS NULL" + else + collector << " = " + visit right, collector + end + end + + def visit_Arel_Nodes_IsNotDistinctFrom(o, collector) + if o.right.nil? + collector = visit o.left, collector + collector << " IS NULL" + else + collector = is_distinct_from(o, collector) + collector << " = 0" + end + end + + def visit_Arel_Nodes_IsDistinctFrom(o, collector) + if o.right.nil? + collector = visit o.left, collector + collector << " IS NOT NULL" + else + collector = is_distinct_from(o, collector) + collector << " = 1" + end + end + + def visit_Arel_Nodes_NotEqual(o, collector) + right = o.right + + collector = visit o.left, collector + + if right.nil? + collector << " IS NOT NULL" + else + collector << " != " + visit right, collector + end + end + + def visit_Arel_Nodes_As(o, collector) + collector = visit o.left, collector + collector << " AS " + visit o.right, collector + end + + def visit_Arel_Nodes_Case(o, collector) + collector << "CASE " + if o.case + visit o.case, collector + collector << " " + end + o.conditions.each do |condition| + visit condition, collector + collector << " " + end + if o.default + visit o.default, collector + collector << " " + end + collector << "END" + end + + def visit_Arel_Nodes_When(o, collector) + collector << "WHEN " + visit o.left, collector + collector << " THEN " + visit o.right, collector + end + + def visit_Arel_Nodes_Else(o, collector) + collector << "ELSE " + visit o.expr, collector + end + + def visit_Arel_Nodes_UnqualifiedColumn(o, collector) + collector << "#{quote_column_name o.name}" + collector + end + + def visit_Arel_Attributes_Attribute(o, collector) + join_name = o.relation.table_alias || o.relation.name + collector << "#{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, collector); collector << o.to_s; end + + def visit_Arel_Nodes_BindParam(o, collector) + collector.add_bind(o.value) { "?" } + end + + alias :visit_Arel_Nodes_SqlLiteral :literal + alias :visit_Integer :literal + + def quoted(o, a) + if a && a.able_to_type_cast? + quote(a.type_cast_for_database(o)) + else + quote(o) + end + end + + def unsupported(o, collector) + raise UnsupportedVisitError.new(o) + 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, collector) + collector = visit o.left, collector + collector << " #{o.operator} " + visit o.right, collector + 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_Arel_Nodes_UnaryOperation(o, collector) + collector << " #{o.operator} " + visit o.expr, collector + end + + def visit_Array(o, collector) + inject_join o, collector, ", " + end + alias :visit_Set :visit_Array + + def quote(value) + return value if Arel::Nodes::SqlLiteral === value + @connection.quote value + end + + def quote_table_name(name) + return name if Arel::Nodes::SqlLiteral === name + @connection.quote_table_name(name) + end + + def quote_column_name(name) + return name if Arel::Nodes::SqlLiteral === name + @connection.quote_column_name(name) + end + + def maybe_visit(thing, collector) + return collector unless thing + collector << " " + visit thing, collector + end + + def inject_join(list, collector, join_str) + len = list.length - 1 + list.each_with_index.inject(collector) { |c, (x, i)| + if i == len + visit x, c + else + visit(x, c) << join_str + end + } + end + + def boundable?(value) + !value.respond_to?(:boundable?) || value.boundable? + end + + def has_join_sources?(o) + o.relation.is_a?(Nodes::JoinSource) && !o.relation.right.empty? + end + + def has_limit_or_offset_or_orders?(o) + o.limit || o.offset || !o.orders.empty? + end + + # The default strategy for an UPDATE with joins is to use a subquery. This doesn't work + # on MySQL (even when aliasing the tables), but MySQL allows using JOIN directly in + # an UPDATE statement, so in the MySQL visitor we redefine this to do that. + def prepare_update_statement(o) + if o.key && (has_limit_or_offset_or_orders?(o) || has_join_sources?(o)) + stmt = o.clone + stmt.limit = nil + stmt.offset = nil + stmt.orders = [] + stmt.wheres = [Nodes::In.new(o.key, [build_subselect(o.key, o)])] + stmt.relation = o.relation.left if has_join_sources?(o) + stmt + else + o + end + end + alias :prepare_delete_statement :prepare_update_statement + + # 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.offset = o.offset + stmt.orders = o.orders + stmt + end + + def infix_value(o, collector, value) + collector = visit o.left, collector + collector << value + visit o.right, collector + end + + def infix_value_with_paren(o, collector, value, suppress_parens = false) + collector << "( " unless suppress_parens + collector = if o.left.class == o.class + infix_value_with_paren(o.left, collector, value, true) + else + visit o.left, collector + end + collector << value + collector = if o.right.class == o.class + infix_value_with_paren(o.right, collector, value, true) + else + visit o.right, collector + end + collector << " )" unless suppress_parens + collector + end + + def aggregate(name, o, collector) + collector << "#{name}(" + if o.distinct + collector << "DISTINCT " + end + collector = inject_join(o.expressions, collector, ", ") << ")" + if o.alias + collector << " AS " + visit o.alias, collector + else + collector + end + end + + def is_distinct_from(o, collector) + collector << "CASE WHEN " + collector = visit o.left, collector + collector << " = " + collector = visit o.right, collector + collector << " OR (" + collector = visit o.left, collector + collector << " IS NULL AND " + collector = visit o.right, collector + collector << " IS NULL)" + collector << " THEN 0 ELSE 1 END" + end + end + end +end |