92 lines
2.9 KiB
C
92 lines
2.9 KiB
C
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/**
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* @file mix_cc/sql/set.h
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* @brief 设值 语句
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* @author Cat (null.null.null@qq.com)
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* @version 0.1
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* @date 2021-09-17
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*
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* Copyright: Baosight Co. Ltd.
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* DO NOT COPY/USE WITHOUT PERMISSION
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*
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*/
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#pragma once
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#include "mix_cc/sql/public.h"
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#include "mix_cc/sql/statement.h"
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#include "mix_cc/sql/where.h"
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#include <algorithm>
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#include <string>
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namespace mix_cc {
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namespace sql {
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namespace detail {
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template <typename PrevStatement, typename Enable, typename... Values>
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struct set_t_impl;
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template <typename PrevStatement, typename... Values>
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struct set_t_impl<
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PrevStatement,
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std::enable_if_t<PrevStatement::s_text == op::cmd_t::insert_into>,
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Values...> : public prev_statement_t<PrevStatement>,
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public statement_t {
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static constexpr auto s_text = op::cmd_t::set;
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constexpr explicit set_t_impl(PrevStatement prev_st, Values... values)
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: prev_statement_t<PrevStatement>(prev_st),
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values_(hana::make_tuple(values...)) {}
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constexpr auto get_command() {
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std::string op1_str = "VALUES";
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auto col_names =
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hana::transform(values_, [](auto val) { return val.get_col_name(); });
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auto r_str_c = hana::fold_left(
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col_names, [](auto col1, auto col2) { return col1 + "," + col2; });
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auto vals =
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hana::transform(values_, [](auto val) { return val.get_value(); });
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auto r_str_c2 = hana::fold_left(
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vals, [](auto val1, auto val2) { return val1 + "," + val2; });
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return std::string("(") + r_str_c + ")" + op1_str + "(" + r_str_c2 + ")";
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}
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public:
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hana::tuple<Values...> values_;
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};
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template <typename PrevStatement, typename... Values>
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struct set_t_impl<PrevStatement,
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std::enable_if_t<PrevStatement::s_text == op::cmd_t::update>,
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Values...> : public prev_statement_t<PrevStatement>,
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public statement_t {
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static constexpr auto s_text = op::cmd_t::set;
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constexpr explicit set_t_impl(PrevStatement prev_st, Values... values)
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: prev_statement_t<PrevStatement>(prev_st),
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values_(hana::make_tuple(values...)) {}
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constexpr auto get_command() {
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auto vals_str =
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hana::transform(values_, [](auto val) { return val.get_str(); });
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auto r_str_c = hana::fold_left(
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vals_str, [](auto val1, auto val2) { return val1 + "," + val2; });
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return std::string(" ") + s_text.c_str() + " " + r_str_c;
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}
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template <typename... Conditions>
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auto where(Conditions... conditions) {
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return where_t(*this, conditions...);
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}
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public:
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hana::tuple<Values...> values_;
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};
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} // namespace detail
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template <typename PrevStatement, typename... Values>
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struct set_t : public detail::set_t_impl<PrevStatement, void, Values...> {
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constexpr explicit set_t(PrevStatement prev_st, Values... values)
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: detail::set_t_impl<PrevStatement, void, Values...>(prev_st, values...) {
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}
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};
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} // namespace sql
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} // namespace mix_cc
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