This function determines whether an instance of a specified entity exists meeting certain criteria.

Syntax

EXISTS entity [WHERE condition]

• entity - Entity to search for.
• condition - Boolean expression that represents the criterion the instance has to meet.

Return type

• boolean

Examples

Suppose the following data model.

• EXISTS Person returns TRUE
• EXISTS Person WHERE (Person.age < 18) returns FALSE
• EXISTS Person WHERE (Person.gender = “m” AND Person.age > 35) returns TRUE

Use this function to create a collection of all instances of a specified entity.

Syntax

ALL entity

• entity - Entity of which to collect all its instances.

Return type

• collection of entity instances

Examples

Suppose the following data model. The Parent and Child entities both have Person as base entity.

• ALL Parent returns a collection of Parent_1 and Parent_2
• ALL Child returns a collection of Child_1, Child_2, Child_3 and Child_4
• ALL Person returns a collection of Parent_1, Parent_2, Child_1, Child_2, Child_3 and Child_4

Use this function to create a collection of entity or attribute instances (meeting certain criteria).

Syntax

COLLECT entity | attribute FROM collection [WHERE expression]

• entity or attribute - Entity or attribute to collect.
• collection - A collection of entity instances.
• expression - Boolean expression that represents the criterion the instance has to meet.

Return type

• collection of entity instances
• collection of attribute values

Examples

Suppose the following model. Entity Teacher has a multivalued relation with entity Child via the relation Teacher.teaches_Children.

• COLLECT Child.name FROM ALL Child results in a collection of the values “Kim”, “Rick”, “Bob” and “Mary”
• COLLECT Child FROM Teacher[Teacher_2].teaches_Children results in a collection of the instances Child_1, Child_3 and Child_4
• COLLECT Child.hobbies FROM Teacher[Teacher_1].teaches_Children results in a collection of the values “Reading”, “Dancing”, “Tennis”, “Painting” and “Basketball”
• COLLECT Child.name FROM ALL Child WHERE (Child.hobbies = “Reading”) results in a collection of the values “Kim” and “Bob”
• COLLECT Child.hobbies FROM ALL Child WHERE (Child.name = “Mary”) results in a collection of the value “Football”

Use this version of the COLLECT FROM [WHERE] function for complex nested selections in which it is necessary to use an alias.

Syntax

COLLECT entity | attribute FROM collection NAMED alias [WHERE expression]

• entity or attribute - Entity or attribute to collect.
• collection - A collection of entity instances.
• alias - A name for the collection.
• expression - Boolean expression that represents the criterion the instance has to meet.

Return type

• collection of entity instances
• collection of attribute values

Examples

Suppose the following model with only instances of entity Person. Person.hasChild is a relation from Person to Person.

To retrieve all the parent names, we use this expression:

COLLECT Parent.name 
FROM (
  COLLECT Person 
  FROM ALL Person 
  WHERE (Person.hasChild != ?)) NAMED Parent
}

This expression results in “Rick”, “Julia” and “Joan”.

To retrieve all children names, we use this expression:

COLLECT Child
FROM (
  COLLECT Person.hasChildren 
  FROM ALL Person 
  WHERE (Person.hasChildren != ?)) NAMED Child

This expression results in a collection of “Kim”, “Bob” and “Sam”.

To retrieve all children younger than 15, we use this expression:

COLLECT Child 
FROM (
  COLLECT Person.hasChildren
  FROM ALL Person 
  WHERE (Person.hasChildren != ?)) NAMED Child
WHERE (Child.Age < 15)

This expression results in a collection of the instances “Bob” and “Sam”.

To retrieve the children’s names with a parent older than 40 years:

COLLECT Child.Name 
FROM (
  COLLECT Person.hasChildren 
  FROM ALL Person 
  WHERE (Person.hasChildren != ? AND Person.Age > 40)) NAMED Child  

This expression results in a collection of “Kim”.

You can make it as complex as you like, for example:

COLLECT Child.Name 
FROM (
  COLLECT Parent.hasChildren
  FROM (
    COLLECT Person
    FROM ALL Person 
    WHERE (Person.hasChildren != ?)) NAMED Parent
  WHERE (Parent.Age > 40 )
) NAMED Child 
WHERE (Child.Age < 18) 

This expression results in a collection of “Kim”.

Use this function to get the content of a single-valued collection.

Syntax

UNPACK collection

• collection - A collection of one entity or attribute instance.

Return type

• entity instance
• attribute value of any type

Examples

Suppose the following data model.

• UNPACK(COLLECT Person.name FROM ALL Person WHERE (Person.SequenceNumber = MIN(COLLECT Person.SequenceNumber FROM ALL Person))) results in “Ron”
• UNPACK(COLLECT Person.name FROM ALL Person WHERE (Person.SequenceNumber = MAX(COLLECT Person.SequenceNumber FROM ALL Person))) results in “Jenny”

Convert a value of one data type into a value of another data type using conversion functions. The following conversion functions are available:

• from string to integer, number, currency, percentage, date, dateTime or boolean
• from integer to string, number, currency or percentage
• from number to string, integer, currency or percentage
• from currency to string, integer or number
• from percentage to string, integer or number
• from date to string or dateTime
• from dateTime to string or date
• from boolean to string, integer or number

Syntax

TEXT(integer, [format], [locale])
TEXT(number, [format], [locale])
TEXT(currency, [format], [locale])
TEXT(percentage, [format], [locale])
TEXT(date, [format])
TEXT(dateTime, [format])
TEXT(boolean, [format])

INTEGER(string, [format], [locale])
INTEGER(number)
INTEGER(currency)
INTEGER(percentage)
INTEGER(boolean)

NUMBER(string, [format], [locale])
NUMBER(integer)
NUMBER(currency)
NUMBER(percentage)
NUMBER(boolean)

CURRENCY(string, [format], [locale]
CURRENCY(integer)
CURRENCY(number)

PERCENTAGE(string, [format], [locale]
PERCENTAGE(integer)
PERCENTAGE(number)

DATE(string, [format])
DATE(dateTime)

DATETIME(string, [format])
DATETIME(date)

BOOLEAN(string, [format])

• value - The value of the date type that is converted.
• format - The format used for conversion. Format must be enclosed by quotes, e.g. “00.00”.
• locale - Locale specifies a combination of language and country. A locale in the option set will override the one that is used as default in the project. Commonly used are en-US, en-GB, nl-NL, nl-BE, fr-FR. The list of language codes can be found here. A list of country codes can be found here.

Examples

• TEXT(PERCENTAGE(1.2), “00.00”, “nl-NL”) results in a string value “01,20”
• INTEGER(“1,0”, ”#0.0”, “nl-NL”) results in an integer value 1
• NUMBER(TRUE) results in a number value 1.0000
• CURRENCY(“1.2”, “invalidPattern”) results in a currency value 1.20 (an unknown pattern will be ignored)
• DATETIME(“19861221 12:02:56”, “yyyyMMdd HH:mm:ss”) results in a dateTime value 1986-12-21T12:02:56
• BOOLEAN(“1”,”1;0”) results in a boolean value TRUE

Formats in the runtime

Each data type is defined in the runtime as follows:

• INTEGER #0
• NUMBER #0.0000
• CURRENCY #0.00
• PERCENTAGE #0.00
• BOOLEAN true,1;false,0

E.g.: numbers will always be shown with 4 decimals.

This function replaces a value if that value is unkown.

Syntax

ISUNKNOWN(attribute, value)

• attribute - Attribute of which the value has to be returned if that value is known.
• value - Value to return if the attribute value is unknown.

Return type

• any type, equals the attribute type

Examples

Suppose the following data model.

• for Jane, ISUNKNOWN(Person.SequenceNumber, 999) returns 999
• for Mary, ISUNKNOWN(Person.SequenceNumber, 999) returns 667

Use this function to check the type of an instance. The function returns TRUE if the selected instance is of the specified entity.

Syntax

instance IS A entity_name

• instance - Instance to check.
• entity_name - Name of the entity as string.

Return type

• boolean

Examples

Suppose a domain model in which there is a singleton entity Residence that has a multivalued relation hasRooms with Room. Room is the base entity for singleton Kitchen and not singletons Bedroom and Bathroom.

If you want to determine the number of bedrooms is the residence:

• COUNT(COLLECT Room FROM Residence.hasRooms WHERE (Room IS A “Bedroom”))

If you want to determine the number of bathrooms is the residence:

• COUNT(COLLECT Room FROM Residence.hasRooms WHERE (Room IS A “Bathroom”))

Use this function to determine the type of an instance. The function returns the name of the entity.

Syntax

TYPE OF base_entity

• base_entity - Name of the instance's base entity.

Return type

• string

Examples

Suppose a domain model in which there is a singleton entity Residence that has a multivalued relation hasRooms with Room. Room is the base entity for singleton Kitchen and not singletons Bedroom and Bathroom.

• for the Kitchen instance the expression TYPE OF Room results in “Kitchen”
• for the Bedroom instances the expression TYPE OF Room = “Bedroom” results in TRUE

This system attribute is obsolete since studio version 7.0. With the introduction of processes a new concept 'privilege' was introduced to replace the authorization concept. Therefor the system attribute was also replaced. For backwards compatibility reasons, after logging on to the runtime, the system.authorizationroles attribute will be filled with the user's privileges.

See also: Privileges

You can get the name of the current channel by using the system attribute system.channel. This is a predefined system attribute, so you don’t have to create it yourself.

At run-time the system returns a string value with the channel you choose while logging on. This value is assigned to the attribute system.channel.

You can get the name of the current language by using the system attribute system.language. This is a predefined system attribute, so you don’t have to create it yourself.

At run-time the system returns a string value with the language that you choose while logging on. This value is assigned to the attribute system.language.

You can get the name of the current page by using the system attribute system.currentpage. This is a predefined system attribute, so you don’t have to create it yourself.

At run-time the system returns a string value with the page name of the page you are on, this value is assigned to the attribute system.currentpage.

You can get the name of the current privileges by using the system attribute system.privileges. This is a predefined system attribute, so you don’t have to create it yourself.

At run-time the system returns a list of string values of the privileges that you choose while logging on. These values are assigned to the attribute system.privileges.

You can capture the parameters associated with an event by using the system attribute system.event. This is a predefined system attribute, so you don’t have to create it yourself.

At run-time the system returns the string values with the parameters associated with the event on the current page. This value is assigned to the attribute system.event.

Beside these user defined event parameters, there are some container types that come with their own built-in buttons. Some older¹⁾ containertypes can throw a 'default event' with associated event parameters. Standard container types with this behaviour are:

Even though some action labels are the same, the system handles them in a different way, this depends on the context. For instance ‘Edit’ will open an existing instance, ‘Add’ will create a new instance, however the action ‘_edit_instance’ is the same.

Special behaviour of the AQ_InstanceSelector

The AQ_InstanceSelector adds the following actions to system.event, depending on the action that was taken in the instance selector:

• _add_instance: this action is added when a new instance is created
• _edit_instance: this action is added when an existing instance has been edited
• _delete_instance: this action is added when an instance has been deleted
• _update_instance: this action is added when an instance has been updated

instanceType<entity name>: this action describes the entity of the instance that has been edited. For example, adding an instance of type Person puts the following actions in system.event: “_add_instance, instanceType_Person”