GMQL Functions

GMQL supports the following functions:

• avg(.) – average value
• count(.) – total number of non-null values.
• count(., true) – distinct count, i.e. total number of distinct values
• max(.) – biggest value
• min(.) – smallest value
• sum(.) – sum of all values

Only select queries can carry out the above aggregate functions.

• now() - returns the current time and date
• fullText(., .) – performs a full text search
• localize(., .) – returns the localized value, according to country code
• concatenation(...) – joins two strings together
• lower(.) – converts string to lower case
• upper(.) – converts string to upper case
• toString(.) – converts value to string
• username() - returns the username of the currently logged in user

avg(sourceProperty)

The avg() function returns the average of all values counted; the values are provided to the average function via the property passed to the function. The type of property that is defined in the function must be a countable, that is, a numeric, type.

Only select queries can carry out avg functions.

Syntax

select avg(ALIAS.PROPERTY_NAME) from TYPE_SIGNATURE ALIAS

The following query will produce the average age of all Person instances:

select avg(p.age) from com.braintribe.model.Person p

count(sourceProperty, distinct)

The count() function counts the amount of non null values occurring in the property passed to it. There is a second parameter, distinct, a Boolean value that defines whether only unique values should be counted (false) or all non null values (true). If you do not pass this second parameter, the value of it defaults to false, and returns only the count for distinct values.

If the property passed to the count function is of a collection type, all elements in each collection will be counted and the total returned.

Only select queries can carry out count functions.

Syntax

Return the total amount of distinct non null values occurring in a property:

select count(ALIAS.PROPERTY_NAME) from TYPE_SIGNATURE ALIAS

You can return the amount of all non null values by using the false parameter.

select count(ALIAS.PROPERTY_NAME, true) from TYPE_SIGNATURE ALIAS

• distinct == false Returns the total amount of non null values for the property age.

  select count(p.age) from com.braintribe.model.Person p
  

• distinct == true Returns the total amount of distinct non null values for the property age.

  select count(p.age, true) from com.braintribe.model.Person p
  

max(sourceProperty)

The max() function returns the largest value of the property passed to it. The property type passed must be a numeric type.

Only select queries can carry out the max function.

Syntax

Return the largest value contained in the property passed:

select max(ALIAS.PROPERTY_NAME) from TYPE_SIGNATURE ALIAS

The following returns the value of the oldest age found in the age property of the Person instances:

select max(p.age) from com.braintribe.model.Person p

min(sourceProperty)

The min() function returns the smallest value of the property passed to it. The property type passed must be a numeric type.

Only select queries can carry out the min function.

Syntax

Return the smallest value of the property passed:

select min(ALIAS.PROPERTY_NAME) from TYPE_SIGNATURE ALIAS

Returns the value of the smallest (in this case, youngest) age found in the age property of the Person instances:

select min(p.age) from com.braintribe.model.Person p

sum(sourceProperty)

The sum() function returns the total sum of all values of a numeric property passed to it.

Only select queries can carry out the sum function.

Syntax

Returns the total sum of all values of the property passed:

select sum(ALIAS.PROPERTY_NAME) from TYPE_SIGNATURE ALIAS

Returns the total sum of all ages found in the property ages of the Person instances:

select sum(p.age) from com.braintribe.model.Person p

now()

The now() function returns the system's current time and date, which can be used either to display the current time or as part of a value comparison.

Syntax

• Select Query

  select now()from TYPE_SIGNATURE ALIAS where now() OPERATOR VALUE
  

  The following query will use the current date as a comparison. It will compare a property called lastLogin from an entity User to show all Users who have at that moment logged in.

  select now() from com.braintribe.model.user.User u where u.lastLogin = now()
  

• Entity Query

  Since the entity query cannot select which specific properties should be returned (for example, using select in a select query), the now() keyword can only be used in a value comparison.

  from TYPE_SIGNATURE ALIAS where now() OPERATOR VALUE
  

  The following query will use the current date as a comparison. It will compare a property called lastLogin from an entity User to show all Users who have at that moment logged in.

  from com.braintribe.model.user.User u where u.lastLogin = now()
  

• Property Query

  The property query can only make value comparisons on properties that are of a collection type (List, Set, Map).

  property PROPERTY_REFERENCE of reference(TYPE_SIGNATURE, ID) where now() OPERATOR VALUE
  

  For example:

  property favouritePersons of reference(com.braintribe.model.Person,5L) p where now() = lastLogon
  

fullText(alias, string)

The fullText() function performs a full text search on a specific entity, and contains two parameters:

• alias – defines the source entity where the full text should be executed
• string – defines the search string that is used by the full text

The full text search is used as part of a value comparison.

The search phrase must be a string, therefore it must be surrounded by single quotation marks ' ', for example: 'search phrase'

Syntax

• Select Query

  select ENTITY_PROPERTIES | * from TYPE_SIGNATURE ALIAS where fullText(ALIAS, SEARCH_PHRASE)
  

  The following query returns all entities containing the full text phrase 'Smith':

  select * from com.braintribe.model.user.User u where fullText(u, 'Smith')
  

• Entity Query

  from TYPE_SIGNATURE ALIAS where fullText(ALIAS, SEARCH_PHRASE)
  

  The following query returns all entities containing the full text search phrase 'cortex':

  select * from com.braintribe.model.user.User u where fullText(u, 'cortex')
  

• Property Query

  Full text searches can only be carried out on properties that are of a collection type, since these are the only property types that can be compared; all other types return a single value or instance.

  property PROPERTY_REFERENCE ALIAS of reference(TYPE_SIGNATURE, ID) where fullText(ALIAS, SEARCH_PHRASE)
  

  For example:

  property roles r of reference(com.braintribe.model.user.User, 'cortex') where fullText(r, 'admin')
  

localize(value, string)

The localize provides the corresponding localized value according to the language code passed. This function is used only on properties that are of the LocalizedString type, which contains a map whose key contains a language code and its value, the corresponding word or phrase in the that language.

The function contains two parameters:

• value – defines the property where the LocalizedString is found
• string – the key value of the LocaizedString map, defining the language code.

Syntax

select localize(LOCALIZED_STRING_PROPERTY, 'LOCALIZED_CODE') from TYPE_SIGNATURE ALIAS

The following will provide the results of the property jobDescription for the instances of the entity Person in German.

select localized(p.jobDescription, 'de')from com.braintribe.model.Person p

concatenation(stringType | stringFunction)

The concatenation() function merges two strings together, which can then either be displayed as part of the returned results or as part of a value comparison. For example, two values are provided StringA and StringB; the result of this concatenation is StringAStringB. This function accepts either string types or a string function.

The function can be passed as many string types as is required, with each passed string type being separated by a comma.

Syntax

• Select Query

  The concatenation() function used as part of a value comparison:

  select * from TYPE_SIGNATURE ALIAS where concatenation(STRING_TYPE OR STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Displays the concatenation as part of the select query:

  select concatenation(STRING_TYPE OR STRING_FUNCTION) from TYPE_SIGNATURE
  

  This query will concatenate the two properties p.firstName and p.lastName before comparing it to a specific value:

  select * from com.braintribe.model.Person p where concatenation(p.firstName, p.lastName) = 'DavidRoberts'
  

  It is also possible to use string functions within the concatenation function u.firstName is converted to lowercase using lower and concatenated with u.lastName; all User instances where the result of the concatenation is robertTaylor.

  select * from com.braintribe.model.user.User u where concatenation(lower(u.firstName), u.lastName) = 'robertTaylor'
  

• Entity Query

  from TYPE_SIGNATURE where concatenation(STRING_TYPE OR STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  This query will concatenate the two properties firstName and lastName before comparing it to a specific value:

  from com.braintribe.model.Person where concatenation(firstName, lastName) = 'DavidRoberts'
  

• Property Query

  The property query can only carry out value comparisons on properties that are of a collection type (List, Set, Map).

  property PROPERTY_REFERENCE of reference(TYPE_SIGNATURE, ID) where concatenation(STRING_TYPE OR STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  This query will concatenate two property values and compare it to a specific value.

  property favouritePersons of reference(com.braintribe.model.Person, 5L) where concatenation(firstName, lastName) like 'DavidRoberts'
  

lower(string | stringFunction)

The lower() function is used to convert strings to all lowercase – a value, for example, Smith, is converted to smith This function can only be carried on properties of the type string or string functions, which can then either be displayed as part of the returned results or as part of a value comparison.

The function can be passed as many string types as is required, with each passed string type being separated by a comma.

Syntax

• Select Query

  select * from TYPE_SIGNATURE ALIAS where lower(STRING_TYPE OR STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Returns all instances of the Person entity when the lowercase of p.firstName is equal to robert.

• Entity Query

  from TYPE_SIGNATURE ALIAS where lower(STRING_TYPE OR STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Returns all instances of the Person entity when the lowercase of p.firstName is equal to robert.

  from com.braintribe.model.Person p where lower(p.firstName) = 'robert'
  

• Property Query

  The property query can only carry out value comparisons on properties that are of a collection type (List, Set, Map).

  property PROPERTY_REFERENCE of reference(TYPE_SIGNATURE, ID) where lower(STRING_TYPE OR STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Returns all instances of the User entity when the lowercase of l.firstName is equal to john.

  property users u of reference(com.braintribe.model.user.Group, 'operators') where lower(u.firstName) like 'john'
  

upper(string | stringFunction)

The upper() function is used to convert strings to all uppercase – a value, for example, smith, is converted to SMITH. This function can only be carried on properties of the type string or string functions, which can then either be displayed as part of the returned results or as part of a value comparison.

The function can be passed as many string types as is required, with each passed string type being separated by a comma.

• Select Query

  select * from TYPE_SIGNATURE ALIAS where upper(STRING_TYPE, OR_STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Returns all instances of Person when the uppercase value of p.firstName is equal to ROBERT:

  select * from com.braintribe.model.Person p where upper(p.firstName) = 'ROBERT'
  

• Entity Query

  from TYPE_SIGNATURE ALIAS where upper(STRING_TYPE, OR_STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Returns all instances of Person when the uppercase value of p.firstName is equal to ROBERT:

  from com.braintribe.model.Person p where upper(p.firstName) = 'ROBERT'
  

• Property Query

  The property query can only carry out value comparisons on properties that are of a collection type (List, Set, Map):

  property PROPERTY_REFERENCE of reference(TYPE_SIGNATURE, ID)where upper(STRING_TYPE, OR_STRING_FUNCTION) COMPARISON_OPERATOR COMPARISON_OPERAND
  

  Return all instances of User contained in users of the Group entity with the ID admins where the uppercase value of u.lastName is equal to SMITH.

  property users u of reference(com.braintribe.model.user.Group, 'admins') where upper(u.lastName) like 'SMITH'
  

toString(string | stringFunction | sourceProperty)

The toString() function is used to convert parameters passed to a string type. This function can be carried out on properties of any type or on string functions, which can then either be displayed as part of the returned results or as part of a value comparison.

• Select Query

  select toString(VALUE_TO_STRING) from TYPE_SIGNATURE ALIAS
  select ENTITY_PROPERTIES|* from TYPE_SIGNATURE ALIAS where toString(STRING_TYPE OR STRING_FUNCTION) OPERATOR OPERAND
  

  Returns all instances of Person, selecting the property dateOfBirth, returned as a string:

  select toString(p.dateOfBirth) from com.braintribe.model.Person p
  

  Returns all instances of Person, selecting firstName and lastName properties when the toString value of dateOfBirth matches the string comparison:

  select p.firstName, p.secondName from com.braintribe.custom.model.Person p where toString(p.dateOfBirth) like  'Wed Aug 19 14:23:00 CEST 1987'
  

• Property Query

  property PROPERTY_REFERENCE of reference(TYPE_SIGNATURE, ID) where toString(STRING_TYPE OR STRING_FUNCTION) OPERATOR OPERAND
  

  Return all instances of User in users of Group entity with the ID operators when the value of u.name is equal to smith.

  property users u of reference(com.braintribe.model.user.Group, 'operators') where toString(u.name) like 'john.smith'
  

username()

The username() function returns the name of the user that is currently logged in.

Imagine you have an entity type in your model called Document which has a property called owner. The owner property contains a username. Let's also assume you want to build a query that searches through all documents that have the current user set as owner.

You could, of course, build individual queries with the username hardcoded. You could also build a single generic query with the username() function:

from Document d where d.owner = username()

Note that the function simply returns the current username and it is up to you to use it somewhere in your query.