DatabaseFieldOptions

Description

The DatabaseFieldOptions object defines additional options for a database field represented by a DataObject. It can be set through attached properties or instantiated as an arbitrarily-named custom property of the corresponding DataObject. See the example for details.

This object was introduced in InCore 1.1.

› Inherits:: Object

Overview

Methods

Signals

Object.completed()

Enumerations

ForeignKeyConstraint

Properties

autoIncrement

This property holds whether this field should be marked as auto-increment if this field is the primary key as well.

› Type:: Boolean
› Default:: false
› Signal:: autoIncrementChanged()
› Attributes:: Writable

blank

This property holds whether to allow this field to be empty when inserting a new data row.

› Type:: Boolean
› Default:: false
› Signal:: blankChanged()
› Attributes:: Writable

dbColumn

This property holds the name of the database column for the field, otherwise per default the object ID is be used.

› Type:: String
› Signal:: dbColumnChanged()
› Attributes:: Writable

dbIndex

This property holds whether to create an index on this field.

› Type:: Boolean
› Default:: false
› Signal:: dbIndexChanged()
› Attributes:: Writable

maxLength

This property holds the maximum length of the field used when creating the database table. Leave at 0 to disable a maximum length.

› Type:: SignedInteger
› Default:: 0
› Signal:: maxLengthChanged()
› Attributes:: Writable

notNull

This property holds whether to insert empty values or NULL values if the field value is empty or not specified.

› Type:: Boolean
› Default:: true
› Signal:: notNullChanged()
› Attributes:: Writable

onDelete

This property holds the foreign key constraint to create on this field. See SQL Server Foreign Key Update and Delete Rules and the ForeignKeyConstraint enumeration for details.

› Type:: ForeignKeyConstraint
› Default:: DatabaseFieldOptions.NoAction
› Signal:: onDeleteChanged()
› Attributes:: Writable

primaryKey

This property holds whether to use this field as the primary key. If no primary key is explicitly defined, an auto-increment integer field will be added.

› Type:: Boolean
› Default:: false
› Signal:: primaryKeyChanged()
› Attributes:: Writable

unique

This property holds whether this field must be unique throughout the table.

› Type:: Boolean
› Default:: false
› Signal:: uniqueChanged()
› Attributes:: Writable

Enumerations

ForeignKeyConstraint

This enumeration describes all possible constraints which can be set for foreign keys.

Name	Value	Description
`DatabaseFieldOptions.NoAction`	`0`	No constraint will be set.
`DatabaseFieldOptions.Restrict`	`1`	Operation not allowed if it would alter the integrity of the database.
`DatabaseFieldOptions.Cascade`	`2`	The change is allowed and propagates on the child table. For example, if a parent row is deleted, the child row is also deleted; if a parent row’s ID changes, the child row’s ID will also change.
`DatabaseFieldOptions.SetNull`	`3`	The change is allowed and the child row’s foreign key columns are set to `NULL`. .

Example

import InCore.Foundation 2.5
import InCore.Database 2.5

Application {

    LocalDatabase {
        id: exampleDatabase

        DatabaseTable {
            id: messages

            DateTime {
                id: date
                DatabaseFieldOptions.dbIndex: true
            }
            DataObject {
                id: text
                dataType: DataObject.String
                data: "<default message>"
                property var options : DatabaseFieldOptions { maxLength: 127; notNull: true }
            }
        }
    }

    onCompleted: messages.submit()
}