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())
	Constructor. More...

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

virtual	~QgsField ()
	Destructor. More...

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...

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

QString	defaultValueExpression () 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...

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	setDefaultValueExpression (const QString &expression)
	Sets an expression to use when calculating the default value 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	setType (QVariant::Type type)
	Set variant type. More...

void	setTypeName (const QString &typeName)
	Set the field 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

QString	defaultValueExpression

bool	isNumeric

int	length

QString	name

int	precision

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 44 of file qgsfield.h.

Constructor & Destructor Documentation

◆ QgsField() [1/2]

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()`
	)

Constructor.

Constructs a new QgsField object.

Parameters

name	Field name
type	Field variant type, currently supported: String / Int / Double
typeName	Field type (eg. 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 (eg. variable character fields)
comment	Comment for the field

Definition at line 46 of file qgsfield.cpp.

◆ QgsField() [2/2]

QgsField::QgsField ( const QgsField & other )

Copy constructor.

Definition at line 52 of file qgsfield.cpp.

◆ ~QgsField()

QgsField::~QgsField ( )

virtual

Destructor.

Definition at line 70 of file qgsfield.cpp.

Member Function Documentation

◆ alias()

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()

Note: added in QGIS 2.18

◆ comment()

QString QgsField::comment ( ) const

Returns the field comment.

◆ convertCompatible()

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 208 of file qgsfield.cpp.

◆ defaultValueExpression()

QString QgsField::defaultValueExpression ( ) 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

Note: added in QGIS 2.18

See also: setDefaultValueExpression()

◆ displayName()

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()

Note: added in QGIS 2.18

Definition at line 89 of file qgsfield.cpp.

◆ displayString()

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

Formats string for display.

Definition at line 188 of file qgsfield.cpp.

◆ isNumeric()

bool QgsField::isNumeric ( ) const

Returns if this field is numeric.

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

Note: added in QGIS 2.18

◆ length()

int QgsField::length ( ) const

Gets the length of the field.

Returns: int containing the length of the field

◆ name()

QString QgsField::name ( ) const

Returns the name of the field.

See also: setName(); displayName()

◆ operator QVariant()

QgsField::operator QVariant ( ) const

inline

Allows direct construction of QVariants from fields.

Definition at line 216 of file qgsfield.h.

◆ operator!=()

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

Definition at line 79 of file qgsfield.cpp.

◆ operator=()

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

Assignment operator.

Definition at line 64 of file qgsfield.cpp.

◆ operator==()

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

Definition at line 74 of file qgsfield.cpp.

◆ precision()

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.

◆ setAlias()

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()

Note: added in QGIS 2.18

Definition at line 177 of file qgsfield.cpp.

◆ setComment()

void QgsField::setComment ( const QString & comment )

Set the field comment.

Definition at line 157 of file qgsfield.cpp.

◆ setDefaultValueExpression()

void QgsField::setDefaultValueExpression ( const QString & expression )

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

Parameters

expression expression to evaluate when calculating default values for field. Pass an empty expression to clear the default.

Note: added in QGIS 2.18

See also: defaultValueExpression()

Definition at line 167 of file qgsfield.cpp.

◆ setLength()

void QgsField::setLength ( int len )

Set the field length.

Parameters

len	Length of the field

Definition at line 148 of file qgsfield.cpp.

◆ setName()

void QgsField::setName ( const QString & name )

Set the field name.

Parameters

name	Name of the field

Definition at line 133 of file qgsfield.cpp.

◆ setPrecision()

void QgsField::setPrecision ( int precision )

Set the field precision.

Parameters

precision Precision of the field

Definition at line 152 of file qgsfield.cpp.

◆ setType()

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

Set variant type.

Definition at line 138 of file qgsfield.cpp.

◆ setTypeName()

void QgsField::setTypeName ( const QString & typeName )

Set the field type.

Parameters

typeName Field type

Definition at line 143 of file qgsfield.cpp.

◆ type()

QVariant::Type QgsField::type ( ) const

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

Definition at line 97 of file qgsfield.cpp.

◆ typeName()

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 102 of file qgsfield.cpp.

Property Documentation

◆ alias

QString QgsField::alias

readwrite

Definition at line 53 of file qgsfield.h.

◆ comment

QString QgsField::comment

readwrite

Definition at line 51 of file qgsfield.h.

◆ defaultValueExpression

QString QgsField::defaultValueExpression

readwrite

Definition at line 54 of file qgsfield.h.

◆ isNumeric

bool QgsField::isNumeric

read

Definition at line 48 of file qgsfield.h.

◆ length

int QgsField::length

readwrite

Definition at line 49 of file qgsfield.h.

◆ name

QString QgsField::name

readwrite

Definition at line 52 of file qgsfield.h.

◆ precision

int QgsField::precision

readwrite

Definition at line 50 of file qgsfield.h.

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

/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsfield.h
/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsfield.cpp

Public Member Functions

Properties

Detailed Description

Constructor & Destructor Documentation

◆ QgsField() [1/2]

◆ QgsField() [2/2]

◆ ~QgsField()

Member Function Documentation

◆ alias()

◆ comment()

◆ convertCompatible()

◆ defaultValueExpression()

◆ displayName()

◆ displayString()

◆ isNumeric()

◆ length()

◆ name()

◆ operator QVariant()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ precision()

◆ setAlias()

◆ setComment()

◆ setDefaultValueExpression()

◆ setLength()

◆ setName()

◆ setPrecision()

◆ setType()

◆ setTypeName()

◆ type()

◆ typeName()

Property Documentation

◆ alias

◆ comment

◆ defaultValueExpression

◆ isNumeric

◆ length

◆ name

◆ precision