pgsql_connect.hpp

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#ifndef NEFORCE_DATABASE_PGSQL_CONNECT_HPP__
#define NEFORCE_DATABASE_PGSQL_CONNECT_HPP__

 
#ifdef NEFORCE_SUPPORT_POSTGRESQL
#    include <libpq-fe.h>
#    include "NeForce/db/sql_connect_base.hpp"
NEFORCE_BEGIN_NAMESPACE__



class NEFORCE_API pgsql_connect final : public sql_connect_base<pgsql_connect> {
protected:
    ::PGconn* link_ = nullptr; 
    friend sql_connect_base<pgsql_connect>;
 
private:
    mutable string last_error_;       
    mutable uint32_t last_errno_ = 0; 
 
public:
    pgsql_connect() = default;

    ~pgsql_connect() override { close(); }
 
    pgsql_connect(const pgsql_connect&) = delete;
    pgsql_connect& operator=(const pgsql_connect&) = delete;

    NEFORCE_NODISCARD bool connect(const db_config& config) override;

    bool reconnect(const db_config& config) override;

    void close() override;

    bool set_character_set(const string& encoding) override;

    NEFORCE_NODISCARD string_view get_character_set() const override;

    NEFORCE_NODISCARD string_view get_error() const override { return last_error_.view(); }

    NEFORCE_NODISCARD uint32_t get_errno() const override { return last_errno_; }

    bool update(const string& sql) const override;

    unique_ptr<idb_tb_result> query(const string& sql) const override;

    unique_ptr<idb_prepared_statement> prepare_statement(const string& sql) const override;

    NEFORCE_NODISCARD bool connected() const override;

    NEFORCE_NODISCARD bool is_valid() const override { return connected(); }
 
    size_t batch_insert(const string& table, const vector<string>& columns,
                        const vector<vector<string>>& rows) override;
 
    // PgSQL table_exists 使用 SELECT EXISTS(...) 模式，不同于基类的简单查询
    NEFORCE_NODISCARD bool table_exists(const string& table) const override;
 
private:
    string begin_sql() { return "BEGIN"; }
    string commit_sql() { return "COMMIT"; }
    string rollback_sql() { return "ROLLBACK"; }
    string table_exists_query(const string& table) const {
        return "SELECT EXISTS (SELECT FROM information_schema.tables WHERE table_name = '" + table + "')";
    }
};

class NEFORCE_API pgsql_factory final : public idb_factory {
public:
    explicit pgsql_factory(db_config config) :
    idb_factory(_NEFORCE move(config)) {}

    ~pgsql_factory() override = default;

    idb_connect* create_connect() override;

    idb_result* create_result(void* native_result) override;
};
 // PostgreSQL
 // Database
 
NEFORCE_END_NAMESPACE__
#endif
#endif // NEFORCE_DATABASE_PGSQL_CONNECT_HPP__