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The first recursive cte compiles

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This commit is contained in:
rbock 2015-02-08 19:47:33 +01:00
parent ee3d803c33
commit c4d77372cf
3 changed files with 62 additions and 12 deletions
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66
include/sqlpp11/cte.h
View File

@ -27,7 +27,9 @@
#ifndef SQLPP_CTE_H
#define SQLPP_CTE_H
#include <sqlpp11/result_row_fwd.h>
#include <sqlpp11/union_data.h>
#include <sqlpp11/select_flags.h>
#include <sqlpp11/result_row.h>
#include <sqlpp11/statement_fwd.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/parameter_list.h>
@ -38,7 +40,7 @@
namespace sqlpp
{
template<typename AliasProvider, typename Statement, typename... ColumnSpecs>
template<typename AliasProvider, typename Statement, typename... FieldSpecs>
struct cte_t;
template<typename FieldSpec>
@ -49,7 +51,7 @@ namespace sqlpp
using _traits = make_traits<value_type_of<FieldSpec>,
tag::must_not_insert,
tag::must_not_update,
tag_if<tag::can_be_null, can_be_null_t<FieldSpec>::value>
tag_if<tag::can_be_null, column_spec_can_be_null_t<FieldSpec>::value>
>;
};
@ -62,14 +64,14 @@ namespace sqlpp
template<typename AliasProvider, typename Statement, typename... FieldSpecs>
struct make_cte_impl<AliasProvider, Statement, result_row_t<void, FieldSpecs...>>
{
using type = cte_t<AliasProvider, Statement, cte_column_spec_t<FieldSpecs>...>;
using type = cte_t<AliasProvider, Statement, FieldSpecs...>;
};
template<typename AliasProvider, typename Statement>
using make_cte_t = typename make_cte_impl<AliasProvider, Statement, get_result_row_t<Statement>>::type;
template<typename AliasProvider, typename Statement, typename... ColumnSpecs>
struct cte_t: public member_t<ColumnSpecs, column_t<AliasProvider, ColumnSpecs>>...
template<typename AliasProvider, typename Statement, typename... FieldSpecs>
struct cte_t: public member_t<cte_column_spec_t<FieldSpecs>, column_t<AliasProvider, cte_column_spec_t<FieldSpecs>>>...
{
using _traits = make_traits<no_value_t, tag::is_cte, tag::is_table>; // FIXME: is table? really?
struct _recursive_traits
@ -83,12 +85,55 @@ namespace sqlpp
using _parameters = parameters_of<Statement>;
using _tags = detail::type_set<>;
};
// FIXME: need a union_distinct and union_all here
// unions can depend on the cte itself In that case the cte is recursive.
using _alias_t = typename AliasProvider::_alias_t;
using _column_tuple_t = std::tuple<column_t<AliasProvider, cte_column_spec_t<FieldSpecs>>...>;
template<typename... T>
using _check = logic::all_t<is_statement_t<T>::value...>;
template<typename Rhs>
auto union_distinct(Rhs rhs) const
-> typename std::conditional<_check<Rhs>::value, cte_t<AliasProvider, union_data_t<void, distinct_t, Statement, Rhs>, FieldSpecs...>, bad_statement>::type
{
static_assert(is_statement_t<Rhs>::value, "argument of union call has to be a statement");
static_assert(has_policy_t<Rhs, is_select_t>::value, "argument of union call has to be a select");
static_assert(has_result_row_t<Rhs>::value, "argument of a union has to be a (complete) select statement");
using _result_row_t = result_row_t<void, FieldSpecs...>;
static_assert(std::is_same<_result_row_t, get_result_row_t<Rhs>>::value, "both select statements in a union have to have the same result columns (type and name)");
return _union_impl<void, distinct_t>(_check<Rhs>{}, rhs);
}
template<typename Rhs>
auto union_all(Rhs rhs) const
-> typename std::conditional<_check<Rhs>::value, cte_t<AliasProvider, union_data_t<void, all_t, Statement, Rhs>, FieldSpecs...>, bad_statement>::type
{
static_assert(is_statement_t<Rhs>::value, "argument of union call has to be a statement");
static_assert(has_policy_t<Rhs, is_select_t>::value, "argument of union call has to be a select");
static_assert(has_result_row_t<Rhs>::value, "argument of a union has to be a (complete) select statement");
using _result_row_t = result_row_t<void, FieldSpecs...>;
static_assert(std::is_same<_result_row_t, get_result_row_t<Rhs>>::value, "both select statements in a union have to have the same result columns (type and name)");
return _union_impl<void, all_t>(_check<Rhs>{}, rhs);
}
private:
template<typename Database, typename Flag, typename Rhs>
auto _union_impl(const std::false_type&, Rhs rhs) const
-> bad_statement;
template<typename Database, typename Flag, typename Rhs>
auto _union_impl(const std::true_type&, Rhs rhs) const
-> cte_t<AliasProvider, union_data_t<void, Flag, Statement, Rhs>, FieldSpecs...>
{
return union_data_t<Database, Flag, Statement, Rhs>{_statement, rhs};
}
public:
cte_t(Statement statement): _statement(statement){}
cte_t(const cte_t&) = default;
cte_t(cte_t&&) = default;
@ -143,6 +188,7 @@ namespace sqlpp
{
static_assert(required_tables_of<Statement>::size::value == 0, "common table expression must not use unknown tables");
static_assert(not detail::is_element_of<AliasProvider, required_ctes_of<Statement>>::value, "common table expression must not self-reference in the first part, use union_all/union_distinct for recursion");
static_assert(is_static_result_row_t<get_result_row_t<Statement>>::value, "ctes must not have dynamically added columns");
return { statement };
}

5
include/sqlpp11/union.h
View File

@ -28,6 +28,7 @@
#define SQLPP_UNION_H
#include <sqlpp11/union_data.h>
#include <sqlpp11/select_flags.h>
#include <sqlpp11/statement_fwd.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/parameter_list.h>
@ -159,9 +160,9 @@ namespace sqlpp
static_assert(has_policy_t<Rhs, is_select_t>::value, "argument of union call has to be a select");
static_assert(has_result_row_t<Rhs>::value, "argument of a union has to be a complete select statement");
static_assert(has_result_row_t<derived_statement_t<Policies>>::value, "left hand side argument of a union has to be a complete select statement or union");
static_assert(std::is_same<get_result_row_t<derived_statement_t<Policies>>, get_result_row_t<Rhs>>::value, "both arguments in a union have to have the same result columns (type and name)");
using _result_row_t = get_result_row_t<Rhs>;
static_assert(std::is_same<get_result_row_t<derived_statement_t<Policies>>, _result_row_t>::value, "both arguments in a union have to have the same result columns (type and name)");
static_assert(is_static_result_row_t<_result_row_t>::value, "unions must not have dynamically added columns");
return _union_impl<void, distinct_t>(_check<derived_statement_t<Policies>, Rhs>{}, rhs);
@ -175,9 +176,9 @@ namespace sqlpp
static_assert(has_policy_t<Rhs, is_select_t>::value, "argument of union call has to be a select");
static_assert(has_result_row_t<Rhs>::value, "argument of a union has to be a (complete) select statement");
static_assert(has_result_row_t<derived_statement_t<Policies>>::value, "left hand side argument of a union has to be a (complete) select statement");
static_assert(std::is_same<get_result_row_t<derived_statement_t<Policies>>, get_result_row_t<Rhs>>::value, "both select statements in a union have to have the same result columns (type and name)");
using _result_row_t = get_result_row_t<Rhs>;
static_assert(std::is_same<get_result_row_t<derived_statement_t<Policies>>, _result_row_t>::value, "both arguments in a union have to have the same result columns (type and name)");
static_assert(is_static_result_row_t<_result_row_t>::value, "unions must not have dynamically added columns");
return _union_impl<void, all_t>(_check<derived_statement_t<Policies>, Rhs>{}, rhs);

3
tests/WithTest.cpp
View File

@ -40,5 +40,8 @@ int main()
db(with(x)(select(x.alpha).from(x).where(true)));
auto y0 = cte(sqlpp::y).as(select(all_of(t)).from(t));
auto y = y0.union_all(select(all_of(y0)).from(y0).where(false));
return 0;
}