Class: QgsFieldConstraints

class qgis.core.QgsFieldConstraints

Bases: sip.wrapper

Constructor for QgsFieldConstraints.

QgsFieldConstraints(QgsFieldConstraints)

Stores information about constraints which may be present on a field.

New in version 3.0: Enums

Methods

constraintDescription Returns the descriptive name for the constraint expression.
constraintExpression Returns the constraint expression for the field, if set.
constraintOrigin Returns the origin of a field constraint, or ConstraintOriginNotSet if the constraint is not present on this field.
constraintStrength Returns the strength of a field constraint, or ConstraintStrengthNotSet if the constraint is not present on this field.
constraints Returns any constraints which are present for the field.
removeConstraint Removes a constraint from the field.
setConstraint Sets a constraint on the field.
setConstraintExpression Set the constraint expression for the field.
setConstraintStrength Sets the strength of a constraint.

Signals

Attributes

ConstraintExpression
ConstraintNotNull
ConstraintOriginLayer
ConstraintOriginNotSet
ConstraintOriginProvider
ConstraintStrengthHard
ConstraintStrengthNotSet
ConstraintStrengthSoft
ConstraintUnique
staticMetaObject
class Constraint

Bases: int

ConstraintExpression = 4
ConstraintNotNull = 1
class ConstraintOrigin

Bases: int

ConstraintOriginLayer = 2
ConstraintOriginNotSet = 0
ConstraintOriginProvider = 1
class ConstraintStrength

Bases: int

ConstraintStrengthHard = 1
ConstraintStrengthNotSet = 0
ConstraintStrengthSoft = 2
ConstraintUnique = 2
class Constraints

Bases: sip.wrapper

QgsFieldConstraints.Constraints(Union[QgsFieldConstraints.Constraints, QgsFieldConstraints.Constraint]) QgsFieldConstraints.Constraints(QgsFieldConstraints.Constraints)

constraintDescription(self) → str

Returns the descriptive name for the constraint expression.

See also

constraints()

constraintExpression(self) → str

Returns the constraint expression for the field, if set.

See also

constraints()

constraintOrigin(self, constraint: QgsFieldConstraints.Constraint) → QgsFieldConstraints.ConstraintOrigin

Returns the origin of a field constraint, or ConstraintOriginNotSet if the constraint is not present on this field.

See also

constraints()

constraintStrength(self, constraint: QgsFieldConstraints.Constraint) → QgsFieldConstraints.ConstraintStrength

Returns the strength of a field constraint, or ConstraintStrengthNotSet if the constraint is not present on this field.

See also

constraints()

constraints(self) → QgsFieldConstraints.Constraints

Returns any constraints which are present for the field.

See also

setConstraint()

removeConstraint(self, constraint: QgsFieldConstraints.Constraint)

Removes a constraint from the field.

See also

setConstraint()

See also

constraints()

setConstraint(self, constraint: QgsFieldConstraints.Constraint, origin: QgsFieldConstraints.ConstraintOrigin = QgsFieldConstraints.ConstraintOriginLayer)

Sets a constraint on the field.

See also

constraints()

setConstraintExpression(self, expression: str, description: str = '')

Set the constraint expression for the field. An optional descriptive name for the constraint can also be set. Setting an empty expression will clear any existing expression constraint.

See also

constraints()

setConstraintStrength(self, constraint: QgsFieldConstraints.Constraint, strength: QgsFieldConstraints.ConstraintStrength)

Sets the strength of a constraint. Note that the strength of constraints which originate from a provider cannot be changed. Constraints default to ConstraintStrengthHard unless explicitly changed.

staticMetaObject = <PyQt5.QtCore.QMetaObject object>