database::core::backend_base< Derived, Type > Class Template Reference

CRTP template base class for database backends. More...

#include <backend_base.h>

Inheritance diagram for database::core::backend_base< Derived, Type >:

Collaboration diagram for database::core::backend_base< Derived, Type >:

Public Member Functions
	backend_base ()=default
	Default constructor.
	~backend_base () override
	Virtual destructor.
	backend_base (const backend_base &)=delete
backend_base &	operator= (const backend_base &)=delete
	backend_base (backend_base &&) noexcept=delete
backend_base &	operator= (backend_base &&) noexcept=delete
database_types	type () const override
	Get the database type of this backend.
kcenon::common::VoidResult	initialize (const connection_config &config) override
	Initialize the database backend.
kcenon::common::VoidResult	shutdown () override
	Shutdown the database backend gracefully.
bool	is_initialized () const override
	Check if backend is initialized and ready.
Public Member Functions inherited from database::core::database_backend
virtual	~database_backend ()=default
virtual kcenon::common::Result< database_result >	select_query (const std::string &query_string)=0
	Execute a SELECT query.
virtual kcenon::common::VoidResult	execute_query (const std::string &query_string)=0
	Execute a general SQL query (DDL, DML)
virtual kcenon::common::Result< database_result >	select_prepared (const std::string &query, const std::vector< database_value > &params)
	Execute a parameterized SELECT query (prepared statement)
virtual kcenon::common::VoidResult	execute_prepared (const std::string &query, const std::vector< database_value > &params)
	Execute a parameterized DML/DDL query (prepared statement)
virtual kcenon::common::VoidResult	begin_transaction ()=0
	Begin a transaction.
virtual kcenon::common::VoidResult	commit_transaction ()=0
	Commit the current transaction.
virtual kcenon::common::VoidResult	rollback_transaction ()=0
	Rollback the current transaction.
virtual bool	in_transaction () const =0
	Check if backend is currently in a transaction.
virtual std::string	last_error () const =0
	Get last error message from backend.
virtual std::map< std::string, std::string >	connection_info () const =0
	Get backend-specific connection information.

Static Public Member Functions
static std::unique_ptr< database_backend >	create ()
	Factory method for backend_registry.

Protected Attributes
std::atomic< bool >	initialized_ {false}
	Initialization state.

Additional Inherited Members
Static Protected Member Functions inherited from database::core::database_backend
static std::string	expand_params (const std::string &query, const std::vector< database_value > &params)
	Expand positional parameters into a SQL string (fallback)

Detailed Description

template<typename Derived, database_types Type>
class database::core::backend_base< Derived, Type >

CRTP template base class for database backends.

This template class implements the common lifecycle pattern shared by all database backends, reducing code duplication and ensuring consistent behavior.

Template Parameters

Derived	The derived backend class (CRTP pattern)
Type	The database_types enum value for this backend

Template Parameters:

• Derived: Must implement:
  • static constexpr const char* backend_name()
  • VoidResult do_initialize(const connection_config&)
  • VoidResult do_shutdown()

Thread Safety:

• initialized_ is atomic for thread-safe state queries
• Derived classes must handle their own synchronization for connection access

Definition at line 73 of file backend_base.h.

Constructor & Destructor Documentation

backend_base() [1/3]

template<typename Derived , database_types Type>

database::core::backend_base< Derived, Type >::backend_base ( )

default

Default constructor.

Initializes the backend in an uninitialized state.

~backend_base()

template<typename Derived , database_types Type>

database::core::backend_base< Derived, Type >::~backend_base ( )

inlineoverride

Virtual destructor.

Calls shutdown() to ensure proper cleanup of derived class resources.

Definition at line 88 of file backend_base.h.

    {
        shutdown();
    }

References database::core::backend_base< Derived, Type >::shutdown().

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backend_base() [2/3]

template<typename Derived , database_types Type>

database::core::backend_base< Derived, Type >::backend_base ( const backend_base< Derived, Type > & )

delete

backend_base() [3/3]

template<typename Derived , database_types Type>

database::core::backend_base< Derived, Type >::backend_base ( backend_base< Derived, Type > && )

deletenoexcept

Member Function Documentation

create()

template<typename Derived , database_types Type>

static std::unique_ptr< database_backend > database::core::backend_base< Derived, Type >::create ( )

inlinestatic

Factory method for backend_registry.

Returns

Unique pointer to new backend instance

Definition at line 105 of file backend_base.h.

    {
        return std::make_unique<Derived>();
    }

initialize()

template<typename Derived , database_types Type>

kcenon::common::VoidResult database::core::backend_base< Derived, Type >::initialize ( const connection_config & config )

inlineoverridevirtual

Initialize the database backend.

Parameters

config

Connection configuration

Returns

VoidResult::ok() on success, error on failure

Performs initialization guard check, then delegates to derived class. Derived class must implement do_initialize() for database-specific logic.

Implements database::core::database_backend.

Definition at line 127 of file backend_base.h.

    {
        if (initialized_) {
            return kcenon::common::error_info{
                static_cast<int>(database::error_code::invalid_state),
                "Backend already initialized",
                Derived::backend_name()
            };
        }
 
        auto result = static_cast<Derived*>(this)->do_initialize(config);
        if (result.is_ok()) {
            initialized_ = true;
        }
        return result;
    }

References database::core::backend_base< Derived, Type >::initialized_, and database::invalid_state.

is_initialized()

template<typename Derived , database_types Type>

bool database::core::backend_base< Derived, Type >::is_initialized ( ) const

inlineoverridevirtual

Check if backend is initialized and ready.

Returns

true if initialized and can accept queries

Implements database::core::database_backend.

Definition at line 166 of file backend_base.h.

    {
        return initialized_;
    }

References database::core::backend_base< Derived, Type >::initialized_.

operator=() [1/2]

template<typename Derived , database_types Type>

backend_base & database::core::backend_base< Derived, Type >::operator= ( backend_base< Derived, Type > && )

deletenoexcept

operator=() [2/2]

template<typename Derived , database_types Type>

backend_base & database::core::backend_base< Derived, Type >::operator= ( const backend_base< Derived, Type > & )

delete

shutdown()

template<typename Derived , database_types Type>

kcenon::common::VoidResult database::core::backend_base< Derived, Type >::shutdown ( )

inlineoverridevirtual

Shutdown the database backend gracefully.

Returns

VoidResult::ok() on success, error on failure

Performs shutdown guard check, then delegates to derived class. Derived class must implement do_shutdown() for database-specific cleanup.

Implements database::core::database_backend.

Definition at line 151 of file backend_base.h.

    {
        if (!initialized_) {
            return kcenon::common::ok();
        }
 
        auto result = static_cast<Derived*>(this)->do_shutdown();
        initialized_ = false;
        return result;
    }

References database::core::backend_base< Derived, Type >::initialized_.

Referenced by database::core::backend_base< Derived, Type >::~backend_base().

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type()

template<typename Derived , database_types Type>

database_types database::core::backend_base< Derived, Type >::type ( ) const

inlineoverridevirtual

Get the database type of this backend.

Returns

Database type identifier from template parameter

Implements database::core::database_backend.

Definition at line 114 of file backend_base.h.

    {
        return Type;
    }

Member Data Documentation

initialized_

template<typename Derived , database_types Type>

std::atomic<bool> database::core::backend_base< Derived, Type >::initialized_ {false}

protected

Initialization state.

Definition at line 172 of file backend_base.h.

{false}; 

Referenced by database::core::backend_base< Derived, Type >::initialize(), database::core::backend_base< Derived, Type >::is_initialized(), and database::core::backend_base< Derived, Type >::shutdown().

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The documentation for this class was generated from the following file:

• database/core/backend_base.h