Represents the many-to-one side of a foreign-key relationship. More...

#include <BelongsTo.hpp>

Public Types
using	ReferencedRecord = MemberClassType< decltype(TheReferencedField)>
	Represents the record type of the other field.

using	BaseType = std::remove_cvref_t< decltype(std::declval< ReferencedRecord >().*ReferencedField)>::ValueType
	Represents the base column type of the foreign key, matching the primary key of the other record.

using	ValueType = std::conditional_t< Nullable==SqlNullable::Null, std::optional< BaseType >, BaseType >

Public Member Functions
template<typename... S> requires std::constructible_from<ValueType, S...>
constexpr	BelongsTo (S &&... value) noexcept
	Constructs a new BelongsTo with the given value(s) forwarded to the underlying value type.

constexpr	BelongsTo (ReferencedRecord const &other) noexcept
	Constructs a new BelongsTo from the given referenced record, copying its primary key.

constexpr	BelongsTo (BelongsTo const &other) noexcept
	Copy constructor.

constexpr	BelongsTo (BelongsTo &&other) noexcept
	Move constructor.

BelongsTo &	operator= (SqlNullType) noexcept
	Assigns NULL to the relationship, clearing the loaded record.

template<typename S > requires (std::constructible_from<ValueType, S> && !std::same_as<std::remove_cvref_t<S>, BelongsTo> && !std::same_as<std::remove_cvref_t<S>, ReferencedRecord> && !std::same_as<std::remove_cvref_t<S>, SqlNullType>)
constexpr BelongsTo &	operator= (S &&value) noexcept

BelongsTo &	operator= (ReferencedRecord &other)
	Assigns a referenced record, updating the foreign key and loaded state.

BelongsTo &	operator= (BelongsTo const &other)
	Copy assignment operator.

BelongsTo &	operator= (BelongsTo &&other) noexcept
	Move assignment operator.

LIGHTWEIGHT_FORCE_INLINE constexpr void	SetModified (bool value) noexcept
	Marks the field as modified or unmodified.

LIGHTWEIGHT_FORCE_INLINE constexpr bool	IsModified () const noexcept
	Checks if the field is modified.

LIGHTWEIGHT_FORCE_INLINE constexpr ValueType const &	Value () const noexcept
	Retrieves the reference to the value of the field.

LIGHTWEIGHT_FORCE_INLINE constexpr ValueType &	MutableValue () noexcept
	Retrieves the mutable reference to the value of the field.

template<typename Self > requires (IsMandatory)
LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord const &	Record (this Self &&self)
	Retrieves a record from the relationship. When the record is not optional.

template<typename Self > requires (IsOptional)
LIGHTWEIGHT_FORCE_INLINE constexpr decltype(auto)	Record (this Self &&self)

template<typename Self > requires (IsMandatory)
LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord &	operator* (this Self &&self) noexcept

template<typename Self > requires (IsMandatory)
LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord *	operator-> (this Self &&self)

LIGHTWEIGHT_FORCE_INLINE constexpr bool	operator! () const noexcept
	Checks if the field value is NULL.

LIGHTWEIGHT_FORCE_INLINE constexpr	operator bool () const noexcept
	Checks if the field value is not NULL.

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord *	LoadedRecord () noexcept
	Returns the already-loaded referenced record, or `nullptr` when none is loaded.

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord const *	LoadedRecord () const noexcept
	Returns the already-loaded referenced record, or `nullptr` when none is loaded.

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord &	EmplaceRecord ()
	Emplaces a record into the relationship. This will mark the relationship as loaded.

LIGHTWEIGHT_FORCE_INLINE void	AdoptFetchedRecord (std::optional< ReferencedRecord > record)

template<typename Stmt >
LIGHTWEIGHT_FORCE_INLINE void	BindOutputColumn (SQLSMALLINT outputIndex, Stmt &stmt)
	Binds the foreign key value to the given output column index on the statement.

std::weak_ordering	operator<=> (BelongsTo const &other) const noexcept
	Three-way comparison operator.

template<detail::FieldElementType T, PrimaryKey IsPrimaryKeyValue = PrimaryKey::No>
std::weak_ordering	operator<=> (Field< T, IsPrimaryKeyValue > const &other) const noexcept
	Three-way comparison operator with a Field.

bool	operator== (BelongsTo const &other) const noexcept
	Equality comparison operator.

bool	operator!= (BelongsTo const &other) const noexcept
	Inequality comparison operator.

template<detail::FieldElementType T, PrimaryKey IsPrimaryKeyValue = PrimaryKey::No>
bool	operator== (Field< T, IsPrimaryKeyValue > const &other) const noexcept
	Equality comparison operator with a Field.

template<detail::FieldElementType T, PrimaryKey IsPrimaryKeyValue = PrimaryKey::No>
bool	operator!= (Field< T, IsPrimaryKeyValue > const &other) const noexcept
	Inequality comparison operator with a Field.

void	SetAutoLoader (Loader loader) noexcept
	Used internally to configure on-demand loading of the record.

Static Public Attributes
static constexpr auto	ReferencedField = TheReferencedField
	The field in the other record that references the current record.

static constexpr std::string_view	ColumnNameOverride
	If not an empty string, this value will be used as the column name in the database.

static constexpr auto	IsOptional = Nullable == SqlNullable::Null
	Indicates whether this relationship is optional (nullable).

static constexpr auto	IsMandatory = !IsOptional
	Indicates whether this relationship is mandatory (non-nullable).

static constexpr auto	IsPrimaryKey = false
	Indicates that a BelongsTo field is never a primary key.

static constexpr auto	IsAutoIncrementPrimaryKey = false
	Indicates that a BelongsTo field is never an auto-increment primary key.

Detailed Description

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>
class Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >

Represents the many-to-one side of a foreign-key relationship.

This is the record that owns the foreign-key column: many records holding a BelongsTo may reference the same target record. For a one-to-one relation through a join table, see HasOneThrough; for the inverse (one-to-many) side, see HasMany.

The TheReferencedField parameter is the field in the other record that references the current record, in the form of &OtherRecord::Field. Other Field must be a primary key.

Template Parameters

TheReferencedField	The field in the other record that references the current record.
ColumnNameOverrideString	If not an empty string, this value will be used as the column name in the database.

struct User {
    Field<SqlGuid, PrimaryKey::AutoAssign> id;
    Field<SqlAnsiString<30>> name;
};
struct Email {
    Field<SqlGuid, PrimaryKey::AutoAssign> id;
    Field<SqlAnsiString<40>> address;
    BelongsTo<&User::id> user;
    // Also possible to customize the column name
    BelongsTo<&User::id, SqlRealName<"the_user_id">, SqlNullable::Null> maybe_user;
};

Definition at line 60 of file BelongsTo.hpp.

Member Typedef Documentation

◆ ReferencedRecord

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

using Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::ReferencedRecord = MemberClassType<decltype(TheReferencedField)>

Represents the record type of the other field.

Definition at line 85 of file BelongsTo.hpp.

◆ BaseType

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

using Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BaseType = std::remove_cvref_t<decltype(std::declval<ReferencedRecord>().*ReferencedField)>::ValueType

Represents the base column type of the foreign key, matching the primary key of the other record.

Definition at line 91 of file BelongsTo.hpp.

◆ ValueType

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

using Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::ValueType = std::conditional_t<Nullable == SqlNullable::Null, std::optional<BaseType>, BaseType>

Represents the value type of the foreign key, which can be either an optional or a non-optional type of the referenced field,

Definition at line 96 of file BelongsTo.hpp.

Constructor & Destructor Documentation

◆ BelongsTo() [1/4]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename... S>
requires std::constructible_from<ValueType, S...>

constexpr Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BelongsTo ( S &&... value )

inlineconstexprnoexcept

Constructs a new BelongsTo with the given value(s) forwarded to the underlying value type.

Definition at line 110 of file BelongsTo.hpp.

◆ BelongsTo() [2/4]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BelongsTo ( ReferencedRecord const & other )

inlineconstexprnoexcept

Constructs a new BelongsTo from the given referenced record, copying its primary key.

Definition at line 116 of file BelongsTo.hpp.

References Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::ReferencedField, and Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::Value().

◆ BelongsTo() [3/4]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BelongsTo ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > const & other )

inlineconstexprnoexcept

Copy constructor.

Definition at line 128 of file BelongsTo.hpp.

◆ BelongsTo() [4/4]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BelongsTo ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > && other )

inlineconstexprnoexcept

Move constructor.

Definition at line 138 of file BelongsTo.hpp.

Member Function Documentation

◆ operator=() [1/5]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

BelongsTo & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator= ( SqlNullType )

inlinenoexcept

Assigns NULL to the relationship, clearing the loaded record.

Definition at line 148 of file BelongsTo.hpp.

◆ operator=() [2/5]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename S >
requires (std::constructible_from<ValueType, S> && !std::same_as<std::remove_cvref_t<S>, BelongsTo> && !std::same_as<std::remove_cvref_t<S>, ReferencedRecord> && !std::same_as<std::remove_cvref_t<S>, SqlNullType>)

constexpr BelongsTo & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator= ( S && value )

inlineconstexprnoexcept

Assigns a bare foreign-key value, updating the foreign key and marking the field modified.

This is the sibling of Field<T>::operator=(S&&). Without it, record.fk = someKeyValue would bind to the converting constructor plus move-assignment, and the temporary's default-constructed _modified (false) would be copied over this field — leaving the change invisible to DataMapper::Update(), which gates its SET clause on IsModified().

Any previously loaded record is dropped, since it no longer corresponds to the new key.

Parameters

value The referenced record's primary-key value to point at.

Returns: Reference to this field.

Definition at line 174 of file BelongsTo.hpp.

◆ operator=() [3/5]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

BelongsTo & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator= ( ReferencedRecord & other )

inline

Assigns a referenced record, updating the foreign key and loaded state.

Definition at line 184 of file BelongsTo.hpp.

References Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::ReferencedField, and Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::Value().

◆ operator=() [4/5]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

BelongsTo & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator= ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > const & other )

inline

Copy assignment operator.

Definition at line 204 of file BelongsTo.hpp.

◆ operator=() [5/5]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

BelongsTo & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator= ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > && other )

inlinenoexcept

Move assignment operator.

Definition at line 219 of file BelongsTo.hpp.

◆ SetModified()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr void Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::SetModified ( bool value )

inlineconstexprnoexcept

Marks the field as modified or unmodified.

Definition at line 235 of file BelongsTo.hpp.

◆ IsModified()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr bool Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::IsModified ( ) const

inlineconstexprnoexcept

Checks if the field is modified.

Definition at line 241 of file BelongsTo.hpp.

◆ Value()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr ValueType const & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::Value ( ) const

inlineconstexprnoexcept

Retrieves the reference to the value of the field.

Definition at line 247 of file BelongsTo.hpp.

Referenced by Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BelongsTo(), and Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator=().

◆ MutableValue()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr ValueType & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::MutableValue ( )

inlineconstexprnoexcept

Retrieves the mutable reference to the value of the field.

Definition at line 253 of file BelongsTo.hpp.

◆ Record() [1/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename Self >
requires (IsMandatory)

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord const & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::Record ( this Self && self )

inlineconstexpr

Retrieves a record from the relationship. When the record is not optional.

Definition at line 262 of file BelongsTo.hpp.

◆ Record() [2/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename Self >
requires (IsOptional)

LIGHTWEIGHT_FORCE_INLINE constexpr decltype(auto) Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::Record ( this Self && self )

inlineconstexpr

Retrieves a record from the relationship. When the record is optional we return object similar to std::optional<ReferencedRecord&>

Definition at line 272 of file BelongsTo.hpp.

◆ operator*()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename Self >
requires (IsMandatory)

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator* ( this Self && self )

inlineconstexprnoexcept

Retrieves the record from the relationship. Only available when the relationship is mandatory.

Definition at line 288 of file BelongsTo.hpp.

◆ operator->()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename Self >
requires (IsMandatory)

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord * Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator-> ( this Self && self )

inlineconstexpr

Retrieves the record from the relationship. Only available when the relationship is mandatory.

Definition at line 298 of file BelongsTo.hpp.

◆ operator!()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr bool Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator! ( ) const

inlineconstexprnoexcept

Checks if the field value is NULL.

Definition at line 308 of file BelongsTo.hpp.

◆ operator bool()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator bool ( ) const

inlineexplicitconstexprnoexcept

Checks if the field value is not NULL.

Definition at line 314 of file BelongsTo.hpp.

◆ LoadedRecord() [1/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord * Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::LoadedRecord ( )

inlineconstexprnoexcept

Returns the already-loaded referenced record, or nullptr when none is loaded.

Unlike Record(), this never runs the on-demand loader: it reports what is present right now. That is what lets the batched relation loading walk one level deeper (With<A, B>()) without turning the walk itself into the N+1 it exists to remove.

Returns: Pointer to the loaded record, or nullptr if the relation is unloaded or NULL.

Definition at line 326 of file BelongsTo.hpp.

◆ LoadedRecord() [2/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord const * Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::LoadedRecord ( ) const

inlineconstexprnoexcept

Returns the already-loaded referenced record, or nullptr when none is loaded.

Unlike Record(), this never runs the on-demand loader: it reports what is present right now. That is what lets the batched relation loading walk one level deeper (With<A, B>()) without turning the walk itself into the N+1 it exists to remove.

Returns: Pointer to the loaded record, or nullptr if the relation is unloaded or NULL.

Definition at line 332 of file BelongsTo.hpp.

◆ EmplaceRecord()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE constexpr ReferencedRecord & Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::EmplaceRecord ( )

inlineconstexpr

Emplaces a record into the relationship. This will mark the relationship as loaded.

Definition at line 338 of file BelongsTo.hpp.

◆ AdoptFetchedRecord()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

LIGHTWEIGHT_FORCE_INLINE void Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::AdoptFetchedRecord ( std::optional< ReferencedRecord > record )

inline

Adopts an eagerly fetched referenced record, marking the relationship loaded.

This is the sink for a record that was already read from the database, as opposed to operator=(ReferencedRecord&), which establishes the relationship and therefore rewrites the foreign key and sets the modified flag. Here the foreign key is already whatever the row said it was, so it is deliberately left untouched and the field stays unmodified - adopting a fetched value is not a pending change to be written back.

An empty record leaves the relationship unloaded rather than clearing the foreign key: a mandatory relationship whose target row is missing is a data-integrity problem to be surfaced by the accessor, not silently turned into NULL.

Parameters

record The fetched record, or std::nullopt if the referenced row was absent.

Definition at line 358 of file BelongsTo.hpp.

◆ BindOutputColumn()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<typename Stmt >

LIGHTWEIGHT_FORCE_INLINE void Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BindOutputColumn	(	SQLSMALLINT	outputIndex,
		Stmt &	stmt
	)

inline

Binds the foreign key value to the given output column index on the statement.

Definition at line 369 of file BelongsTo.hpp.

◆ operator<=>() [1/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

std::weak_ordering Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator<=> ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > const & other ) const

inlinenoexcept

Three-way comparison operator.

Definition at line 375 of file BelongsTo.hpp.

◆ operator<=>() [2/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<detail::FieldElementType T, PrimaryKey IsPrimaryKeyValue = PrimaryKey::No>

std::weak_ordering Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator<=> ( Field< T, IsPrimaryKeyValue > const & other ) const

inlinenoexcept

Three-way comparison operator with a Field.

Definition at line 382 of file BelongsTo.hpp.

◆ operator==() [1/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

bool Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator== ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > const & other ) const

inlinenoexcept

Equality comparison operator.

Definition at line 388 of file BelongsTo.hpp.

◆ operator!=() [1/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

bool Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator!= ( BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable > const & other ) const

inlinenoexcept

Inequality comparison operator.

Definition at line 394 of file BelongsTo.hpp.

◆ operator==() [2/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<detail::FieldElementType T, PrimaryKey IsPrimaryKeyValue = PrimaryKey::No>

bool Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator== ( Field< T, IsPrimaryKeyValue > const & other ) const

inlinenoexcept

Equality comparison operator with a Field.

Definition at line 401 of file BelongsTo.hpp.

◆ operator!=() [2/2]

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

template<detail::FieldElementType T, PrimaryKey IsPrimaryKeyValue = PrimaryKey::No>

bool Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator!= ( Field< T, IsPrimaryKeyValue > const & other ) const

inlinenoexcept

Inequality comparison operator with a Field.

Definition at line 408 of file BelongsTo.hpp.

◆ SetAutoLoader()

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

void Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::SetAutoLoader ( Loader loader )

inlinenoexcept

Used internally to configure on-demand loading of the record.

Definition at line 419 of file BelongsTo.hpp.

Member Data Documentation

◆ ReferencedField

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr auto Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::ReferencedField = TheReferencedField

staticconstexpr

The field in the other record that references the current record.

Definition at line 64 of file BelongsTo.hpp.

Referenced by Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::BelongsTo(), and Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::operator=().

◆ ColumnNameOverride

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr std::string_view Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::ColumnNameOverride

staticconstexpr

Initial value:

= []() consteval {
        if constexpr (!std::same_as<decltype(ColumnNameOverrideString), std::nullopt_t>)
            return std::string_view { ColumnNameOverrideString };
        else
            return std::string_view {};
    }()

If not an empty string, this value will be used as the column name in the database.

Definition at line 67 of file BelongsTo.hpp.

◆ IsOptional

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr auto Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::IsOptional = Nullable == SqlNullable::Null

staticconstexpr

Indicates whether this relationship is optional (nullable).

Definition at line 99 of file BelongsTo.hpp.

◆ IsMandatory

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr auto Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::IsMandatory = !IsOptional

staticconstexpr

Indicates whether this relationship is mandatory (non-nullable).

Definition at line 101 of file BelongsTo.hpp.

◆ IsPrimaryKey

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr auto Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::IsPrimaryKey = false

staticconstexpr

Indicates that a BelongsTo field is never a primary key.

Definition at line 103 of file BelongsTo.hpp.

◆ IsAutoIncrementPrimaryKey

template<auto TheReferencedField, auto ColumnNameOverrideString = std::nullopt, SqlNullable Nullable = SqlNullable::NotNull>

constexpr auto Lightweight::BelongsTo< TheReferencedField, ColumnNameOverrideString, Nullable >::IsAutoIncrementPrimaryKey = false

staticconstexpr

Indicates that a BelongsTo field is never an auto-increment primary key.

Definition at line 105 of file BelongsTo.hpp.

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

Lightweight/DataMapper/BelongsTo.hpp

Public Types

Public Member Functions

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ ReferencedRecord

◆ BaseType

◆ ValueType

Constructor & Destructor Documentation

◆ BelongsTo() [1/4]

◆ BelongsTo() [2/4]

◆ BelongsTo() [3/4]

◆ BelongsTo() [4/4]

Member Function Documentation

◆ operator=() [1/5]

◆ operator=() [2/5]

◆ operator=() [3/5]

◆ operator=() [4/5]

◆ operator=() [5/5]

◆ SetModified()

◆ IsModified()

◆ Value()

◆ MutableValue()

◆ Record() [1/2]

◆ Record() [2/2]

◆ operator*()

◆ operator->()

◆ operator!()

◆ operator bool()

◆ LoadedRecord() [1/2]

◆ LoadedRecord() [2/2]

◆ EmplaceRecord()

◆ AdoptFetchedRecord()

◆ BindOutputColumn()

◆ operator<=>() [1/2]

◆ operator<=>() [2/2]

◆ operator==() [1/2]

◆ operator!=() [1/2]

◆ operator==() [2/2]

◆ operator!=() [2/2]

◆ SetAutoLoader()

Member Data Documentation

◆ ReferencedField

◆ ColumnNameOverride

◆ IsOptional

◆ IsMandatory

◆ IsPrimaryKey

◆ IsAutoIncrementPrimaryKey