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module Arel
module Visitors
class ToSql
def initialize engine
@engine = engine
@connection = nil
end
def accept object
@connection = @engine.connection
visit object
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
def visit_Arel_Nodes_UpdateStatement o
[
"UPDATE #{visit o.relation}",
("SET #{o.values.map { |value| visit value }.join ', '}" unless o.values.empty?),
("WHERE #{o.wheres.map { |x| visit x }.join ' AND '}" unless o.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?),
("VALUES (#{o.values.map { |value|
value ? visit(value) : 'NULL'
}.join ', '})" unless o.values.empty?),
].compact.join ' '
end
def visit_Arel_Nodes_SelectStatement o
[
o.cores.map { |x| visit x }.join,
("ORDER BY #{o.orders.map { |x| visit x }.join(', ')}" unless o.orders.empty?),
("LIMIT #{o.limit}" if o.limit)
].compact.join ' '
end
def visit_Arel_Nodes_SelectCore o
[
"SELECT #{o.projections.map { |x| visit x }.join ', '}",
("FROM #{o.froms.map { |x| visit x }.join ', ' }" unless o.froms.empty?),
("WHERE #{o.wheres.map { |x| visit x }.join ' AND ' }" unless o.wheres.empty?)
].compact.join ' '
end
def visit_Arel_Nodes_TableAlias o
"#{visit o.relation} #{quote_table_name o.name}"
end
def visit_Arel_Nodes_OuterJoin o
"#{visit o.left} OUTER JOIN #{visit o.right} #{visit o.constraint}"
end
def visit_Arel_Nodes_InnerJoin o
"#{visit o.left} INNER JOIN #{visit o.right} #{visit o.constraint}"
end
def visit_Arel_Nodes_On o
"ON #{visit o.expr}"
end
def visit_Arel_Table o
quote_table_name o.name
end
def visit_Arel_Nodes_In o
"#{visit o.left} IN (#{o.right.map { |x| visit x }.join ', '})"
end
def visit_Arel_Nodes_Or o
"#{visit o.left} OR #{visit o.right}"
end
def visit_Arel_Nodes_Equality o
right = o.right
right = right ? visit(right) : 'NULL'
"#{visit o.left} = #{right}"
end
def visit_Arel_Nodes_UnqualifiedColumn o
"#{quote_column_name o.name}"
end
def visit_Arel_Attributes_Attribute o
"#{quote_table_name o.relation.name}.#{quote_column_name o.name}"
end
alias :visit_Arel_Attributes_Integer :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_String :visit_Arel_Attributes_Attribute
alias :visit_Arel_Attributes_Time :visit_Arel_Attributes_Attribute
def visit_Fixnum o; o end
alias :visit_Arel_Nodes_SqlLiteral :visit_Fixnum
alias :visit_Arel_SqlLiteral :visit_Fixnum # This is deprecated
def visit_TrueClass o; quote(o) end
def visit_String o; quote(o) end
def visit_Time o; quote(o) end
DISPATCH = {}
def visit object
send "visit_#{object.class.name.gsub('::', '_')}", object
#send DISPATCH[object.class], object
end
private_instance_methods(false).each do |method|
method = method.to_s
next unless method =~ /^visit_(.*)$/
const = $1.split('_').inject(Object) { |m,s| m.const_get s }
DISPATCH[const] = method
end
def quote value, column = nil
@connection.quote value, column
end
def quote_table_name name
@connection.quote_table_name name
end
def quote_column_name name
@connection.quote_column_name name
end
end
end
end
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