Querying Data (WIP)

Selector Built-in Functions

These functions are available via the object's namespace, e.g. Person:{function}.

They can be used to read sets of data from the persistence layer. The final four in the table below (union, diff, intersect, and and) can be used to build up a complex selector using a combination of other selector BIFs as parameters. The other selectors all take an object's attribute as first parameter, and one or more values as the next parameter(s).

Function	Syntax	Description	Example
`all`	`Obj:all()`	returns all records from the table	`Person[] plist = Person:all();`
`equals`	`Obj:equals(a,b)`	returns records with value of obj.a equal to b	`Person[] plist = Person:equals(deleted, false);`
`notEquals`	Obj:notEquals(a,b)	returns records with value of obj.a not equal to b	`Person[] plist = Person:notEquals(deleted, true);`
`empty`	Obj:empty(a)	returns records with obj.a equal to null	`Person[] plist = Person:empty(mobileNum);`
`between`	Obj:between(a,x,y)	returns records with value of obj.a within the range of values between x and y	`Person[] plist = Person:between(dob, date1, date2);`
`lessThanOrEqual`	Obj:lessThanOrEqual(a,b)	returns records with value of obj.a less than or equal to b	`Person[] plist = Person:lessThanOrEqual(age, num);`
`lessThan`	Obj:lessThan(a,b)	returns records with value of obj.a less than b	`Person[] plist = Person:lessThan(age, num);`
`greaterThan`	Obj:greaterThan(a,b)	Check if value is greater than the value being compared to	`Person[] plist = Person:greaterThan(age, num);`
`attributeIn`	Obj:attributeIn(a,"x,y,z")	Attribute In	`Person[] plist = Person:attributeIn(state, "Any, One, Of, These");`
`relationshipIn`	Obj:relationshipIn(a,b)	Relationship In	`Person[] plist = Person:relationshipIn(reportsTo, person);`
`contains`	Obj:contains(a,b)	Check is collection has element(s)	`Person[] plist = Person:contains(name, "a");`
`beginsWith`		Begin with	`Person[] plist = Person:beginsWith(name, "a");`
`endsWith`		End with	`Person[] plist = Person:endsWith(name, "a");`
`notEmpty`		Not empty	`Person[] plist = Person:notEmpty(mobileNum);`
`notBetween`		Not between the data or elements	`Person[] plist = Person:notBetween(dob, date1, date2);`
`notContains`		Collection does not contain element(s)	`Person[] plist = Person:notContains(name, "a");`
`notBeginWith`		Not begin with	`Person[] plist = Person:notBeginWith(name, "a");`
`notEndsWith`		Check if value does not end with value being compared to	`Person[] plist = Person:notEndsWith(name, "a");`
`notAttributeIn`		Attribute not in the given domain	`Person[] plist = Person:notAttributeIn(state, "Any, One, Of, These");`
`notRelationshipIn`		Use to check for relationship	`Person[] plist = Person:notRelationshipIn(reportsTo, person);`
`union`		Union	`Person[] plist = Person:union(equals(rating, "good"), equals(rating, "excellent"));`
`diff`		Use to check for differences	`Person[] plist = Person:diff(equals(), equals());`
`intersect`		Intersect	`Person[] plist = Person:intersect(equals(deleted, false), equals(active, true));`
`and`		And (in most cases, use this rather than intersect)	`Person[] plist = Person:and(equals(deleted, false), equals(active, true));`

Selector Built-in Functions

Data Subsets

Additional Mentions and References

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