Encapsulate a field in an attribute table or data source. More...

#include <qgsfield.h>

Public Member Functions
	QgsField (const QString &name=QString(), QVariant::Type type=QVariant::Invalid, const QString &typeName=QString(), int len=0, int prec=0, const QString &comment=QString(), QVariant::Type subType=QVariant::Invalid)
	Constructor. More...

	QgsField (const QgsField &other)
	Copy constructor. More...

virtual	~QgsField ()=default

QString	alias () const
	Returns the alias for the field (the friendly displayed name of the field ), or an empty string if there is no alias. More...

QString	comment () const
	Returns the field comment. More...

const QgsFieldConstraints &	constraints () const
	Returns constraints which are present for the field. More...

bool	convertCompatible (QVariant &v) const
	Converts the provided variant to a compatible format. More...

QgsDefaultValue	defaultValueDefinition () const
	Returns the expression used when calculating the default value for the field. More...

QString	displayName () const
	Returns the name to use when displaying this field. More...

QString	displayString (const QVariant &v) const
	Formats string for display. More...

QgsEditorWidgetSetup	editorWidgetSetup () const
	Gets the editor widget setup for the field. More...

bool	isNumeric () const
	Returns if this field is numeric. More...

int	length () const
	Gets the length of the field. More...

QString	name () const
	Returns the name of the field. More...

	operator QVariant () const
	Allows direct construction of QVariants from fields. More...

bool	operator!= (const QgsField &other) const

QgsField &	operator= (const QgsField &other)
	Assignment operator. More...

bool	operator== (const QgsField &other) const

int	precision () const
	Gets the precision of the field. More...

void	setAlias (const QString &alias)
	Sets the alias for the field (the friendly displayed name of the field ). More...

void	setComment (const QString &comment)
	Set the field comment. More...

void	setConstraints (const QgsFieldConstraints &constraints)
	Sets constraints which are present for the field. More...

void	setDefaultValueDefinition (const QgsDefaultValue &defaultValueDefinition)
	Sets an expression to use when calculating the default value for the field. More...

void	setEditorWidgetSetup (const QgsEditorWidgetSetup &v)
	Set the editor widget setup for the field. More...

void	setLength (int len)
	Set the field length. More...

void	setName (const QString &name)
	Set the field name. More...

void	setPrecision (int precision)
	Set the field precision. More...

void	setSubType (QVariant::Type subType)
	If the field is a collection, set its element's type. More...

void	setType (QVariant::Type type)
	Set variant type. More...

void	setTypeName (const QString &typeName)
	Set the field type. More...

QVariant::Type	subType () const
	If the field is a collection, gets its element's type. More...

QVariant::Type	type () const
	Gets variant type of the field as it will be retrieved from data source. More...

QString	typeName () const
	Gets the field type. More...

Properties
QString	alias

QString	comment

QgsFieldConstraints	constraints

QgsDefaultValue	defaultValueDefinition

bool	isNumeric

int	length

QString	name

int	precision

QVariant::Type	type

Detailed Description

Encapsulate a field in an attribute table or data source.

QgsField stores metadata about an attribute field, including name, type length, and if applicable, precision.

Note: QgsField objects are implicitly shared.

Definition at line 48 of file qgsfield.h.

Constructor & Destructor Documentation

QgsField::QgsField	(	const QString &	name = `QString()`,
		QVariant::Type	type = `QVariant::Invalid`,
		const QString &	typeName = `QString()`,
		int	len = `0`,
		int	prec = `0`,
		const QString &	comment = `QString()`,
		QVariant::Type	subType = `QVariant::Invalid`
	)

Constructor.

Constructs a new QgsField object.

Parameters

name	Field name
type	Field variant type, currently supported: String / Int / Double
typeName	Field type (e.g., char, varchar, text, int, serial, double). Field types are usually unique to the source and are stored exactly as returned from the data store.
len	Field length
prec	Field precision. Usually decimal places but may also be used in conjunction with other fields types (e.g., variable character fields)
comment	Comment for the field
subType	If the field is a collection, its element's type. When all the elements don't need to have the same type, leave this to QVariant::Invalid.

Definition at line 47 of file qgsfield.cpp.

QgsField::QgsField ( const QgsField & other )

Copy constructor.

Definition at line 54 of file qgsfield.cpp.

virtual QgsField::~QgsField ( )

virtualdefault

Member Function Documentation

QString QgsField::alias ( ) const

Returns the alias for the field (the friendly displayed name of the field ), or an empty string if there is no alias.

See also: setAlias()

Since: QGIS 3.0

QString QgsField::comment ( ) const

Returns the field comment.

const QgsFieldConstraints& QgsField::constraints ( ) const

Returns constraints which are present for the field.

See also: setConstraints()

Since: QGIS 3.0

bool QgsField::convertCompatible ( QVariant & v ) const

Converts the provided variant to a compatible format.

Parameters

v	The value to convert

Returns: True if the conversion was successful

Definition at line 272 of file qgsfield.cpp.

QgsDefaultValue QgsField::defaultValueDefinition ( ) const

Returns the expression used when calculating the default value for the field.

Returns: expression evaluated when calculating default values for field, or an empty string if no default is set

See also: setDefaultValueDefinition()

Since: QGIS 3.0

QString QgsField::displayName ( ) const

Returns the name to use when displaying this field.

This will be the field alias if set, otherwise the field name.

See also: name(); alias()

Since: QGIS 3.0

Definition at line 87 of file qgsfield.cpp.

QString QgsField::displayString ( const QVariant & v ) const

Formats string for display.

Definition at line 206 of file qgsfield.cpp.

QgsEditorWidgetSetup QgsField::editorWidgetSetup ( ) const

Gets the editor widget setup for the field.

Defaults may be set by the provider and can be overridden by manual field configuration.

Returns: the value

Definition at line 429 of file qgsfield.cpp.

bool QgsField::isNumeric ( ) const

Returns if this field is numeric.

Any integer or floating point type will return true for this.

Since: QGIS 2.18

int QgsField::length ( ) const

Gets the length of the field.

Returns: int containing the length of the field

QString QgsField::name ( ) const

Returns the name of the field.

See also: setName(); displayName()

QgsField::operator QVariant ( ) const

inline

Allows direct construction of QVariants from fields.

Definition at line 316 of file qgsfield.h.

bool QgsField::operator!= ( const QgsField & other ) const

Definition at line 77 of file qgsfield.cpp.

QgsField & QgsField::operator= ( const QgsField & other )

Assignment operator.

Definition at line 66 of file qgsfield.cpp.

bool QgsField::operator== ( const QgsField & other ) const

Definition at line 72 of file qgsfield.cpp.

int QgsField::precision ( ) const

Gets the precision of the field.

Not all field types have a related precision.

Returns: int containing the precision or zero if not applicable to the field type.

void QgsField::setAlias ( const QString & alias )

Sets the alias for the field (the friendly displayed name of the field ).

Parameters

alias field alias, or empty string to remove an existing alias

See also: alias()

Since: QGIS 3.0

Definition at line 195 of file qgsfield.cpp.

void QgsField::setComment ( const QString & comment )

Set the field comment.

Definition at line 165 of file qgsfield.cpp.

void QgsField::setConstraints ( const QgsFieldConstraints & constraints )

Sets constraints which are present for the field.

See also: constraints()

Since: QGIS 3.0

Definition at line 180 of file qgsfield.cpp.

void QgsField::setDefaultValueDefinition ( const QgsDefaultValue & defaultValueDefinition )

Sets an expression to use when calculating the default value for the field.

Parameters

defaultValueDefinition expression to evaluate when calculating default values for field. Pass a default constructed QgsDefaultValue() to reset.

See also: defaultValueDefinition()

Since: QGIS 3.0

Definition at line 175 of file qgsfield.cpp.

void QgsField::setEditorWidgetSetup ( const QgsEditorWidgetSetup & v )

Set the editor widget setup for the field.

Parameters

v	The value to set

Definition at line 424 of file qgsfield.cpp.

void QgsField::setLength ( int len )

Set the field length.

Parameters

len	Length of the field

Definition at line 156 of file qgsfield.cpp.

void QgsField::setName ( const QString & name )

Set the field name.

Parameters

name	Name of the field

Definition at line 136 of file qgsfield.cpp.

void QgsField::setPrecision ( int precision )

Set the field precision.

Parameters

precision Precision of the field

Definition at line 160 of file qgsfield.cpp.

void QgsField::setSubType ( QVariant::Type subType )

If the field is a collection, set its element's type.

When all the elements don't need to have the same type, set this to QVariant::Invalid.

Since: QGIS 3.0

Definition at line 146 of file qgsfield.cpp.

void QgsField::setType ( QVariant::Type type )

Set variant type.

Definition at line 141 of file qgsfield.cpp.

void QgsField::setTypeName ( const QString & typeName )

Set the field type.

Parameters

typeName Field type

Definition at line 151 of file qgsfield.cpp.

QVariant::Type QgsField::subType ( ) const

If the field is a collection, gets its element's type.

When all the elements don't need to have the same type, this returns QVariant::Invalid.

Since: QGIS 3.0

Definition at line 100 of file qgsfield.cpp.

QVariant::Type QgsField::type ( ) const

Gets variant type of the field as it will be retrieved from data source.

QString QgsField::typeName ( ) const

Gets the field type.

Field types vary depending on the data source. Examples are char, int, double, blob, geometry, etc. The type is stored exactly as the data store reports it, with no attempt to standardize the value.

Returns: QString containing the field type

Definition at line 105 of file qgsfield.cpp.

Property Documentation

QString QgsField::alias

readwrite

Definition at line 58 of file qgsfield.h.

QString QgsField::comment

readwrite

Definition at line 56 of file qgsfield.h.

const QgsFieldConstraints & QgsField::constraints

readwrite

Definition at line 60 of file qgsfield.h.

QgsDefaultValue QgsField::defaultValueDefinition

readwrite

Definition at line 59 of file qgsfield.h.

bool QgsField::isNumeric

read

Definition at line 52 of file qgsfield.h.

int QgsField::length

readwrite

Definition at line 53 of file qgsfield.h.

QString QgsField::name

readwrite

Definition at line 57 of file qgsfield.h.

int QgsField::precision

readwrite

Definition at line 54 of file qgsfield.h.

QVariant::Type QgsField::type

readwrite

Definition at line 55 of file qgsfield.h.

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

/build/qgis-3.4.15+24xenial/src/core/qgsfield.h
/build/qgis-3.4.15+24xenial/src/core/qgsfield.cpp

Public Member Functions

Properties

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Property Documentation