Operators and Functions

34 Operators and Functions

This chapter provides a detailed reference to the operators and built-in functions supported in Oracle Backend for Firebase security rule expressions. These tools allow developers to write expressive, conditional logic that governs access to backend resources.

Parent topic: Security Rules

34.1 Operators

Operators are used to perform comparisons, logical evaluations, and arithmetic operations within rule conditions.

Logical Operators

Operator Description Example

Operator	Description	Example
`!a`	Logical NOT	`!request.auth.email_verified` denies access if email is not verified
`a && b`	Logical AND	`request.auth != null && resource.data.uuid == request.auth.uid`
`a \|\| b`	Logical OR This operator returns `true` if either `a` or `b` is true.	`resource.data.isPublic == true \|\| request.auth.uid == resource.data.ownerId`

!a

Logical NOT

!request.auth.email_verified denies access if email is not verified

a && b

Logical AND

request.auth != null && resource.data.uuid == request.auth.uid

a || b

Logical OR

This operator returns true if either a or b is true.

resource.data.isPublic == true || request.auth.uid == resource.data.ownerId

Comparison Operators

Operator	Description	Example
`a == b`	Equal	`resource.data.category == "Dessert"`
`a != b`	Not equal	`resource.data.category != "Dessert"`
`a > b`	Greater than	`resource.data.views > 1000`
`a >= b`	Greater than or equal	`resource.data.views >= 1000`
`a < b`	Less than	`resource.data.views < 1000`
`a <= b`	Less than or equal	`resource.data.views <= 1000`
`a in b`	Value `a` exists in list `b`	`"Dessert" in resource.data.tags`
`a is type`	Type check (For example, `is string`)	`resource.data.title is string`

Arithmetic Operators

Operator	Description	Example
`a + b`	Addition	`resource.data.views + 1`
`a - b`	Subtraction	`resource.data.views - 1`
`a * b`	Multiplication	`resource.data.price * 2`
`a / b`	Division	`resource.data.total / resource.data.count`

Additional Operators

Operator Description Example

Operator	Description	Example
`a[i]`	Indexing operator This operator accesses the element at index `i` in a list `a`.	`request.resource.data.tags[0] == "chocolate"` checks if the first tag in the `tags` array is `"chocolate"`.
`a.f`	Field access operator This operator accesses the field `f` from object `a`.	`request.auth.token.email == "scott@example.com"` accesses the `email` field inside the nested `token` object of the authenticated user. `resource.data.content.step2 == "Add extra chocolate chips"` accesses the `step2` field inside the `content` map of a document.

a[i]

Indexing operator

This operator accesses the element at index i in a list a.

request.resource.data.tags[0] == "chocolate" checks if the first tag in the tags array is "chocolate".

a.f

Field access operator

This operator accesses the field f from object a.

request.auth.token.email == "scott@example.com" accesses the email field inside the nested token object of the authenticated user.

resource.data.content.step2 == "Add extra chocolate chips" accesses the step2 field inside the content map of a document.

Parent topic: Operators and Functions

34.2 Built-in Functions

Oracle Backend for Firebase security rules support a rich set of functions across different data types.

String Functions

Function	Description	Example
`lower()`	Converts to lowercase	`"Burger".lower() == "burger"`
`upper()`	Converts to uppercase	`"Burger".upper() == "BURGER"`
`matches()`	Regex match	`"Chocolate Chip,Corn Flour".matches(".Flour.") == true`
`replace()`	Replace substring	`"ChocolateChip".replace("Chip", "Coco") == "ChocolateCoco"`
`split()`	Split string into list	`"Chocolate,Flour".split(",") == ["Chocolate", "Flour"]`
`trim()`	Remove white (blank) space	`" Chocolate ".trim() == "Chocolate"`
`size()`	String length	`"Chocolate".size() == 9`

List Functions

Function	Description	Example
`concat()`	Merge lists	`["a"].concat(["b"]) == ["a", "b"]`
`hasAll()`	All elements exist	`["a", "b"].hasAll(["a", "b"]) == true`
`hasAny()`	Any element exists	`["a", "b"].hasAny(["b", "c"]) == true`
`hasOnly()`	Only specified elements exist	`["a", "b"].hasOnly(["a", "b", "c"]) == true`
`size()`	List length	`["a", "b"].size() == 2`

Timestamp Functions

Function	Description	Example
`year()`	Extract year	`request.time.year() == 2025`
`month()`	Extract month	`request.time.month() == 11`
`day()`	Extract day	`request.time.day() == 14`
`dayOfWeek()`	Day of week	`request.time.dayOfWeek() == 5`
`dayOfYear()`	Day of year	`request.time.dayOfYear() == 318`
`hours()`	Extract hour	`request.time.hours() >= 9`
`minutes()`	Extract minutes	`request.time.minutes() < 30`
`seconds()`	Extract seconds	`request.time.seconds() < 60`
`nanos()`	Extract nanoseconds	`request.time.nanos() == 0`
`toMillis()`	Convert to milliseconds	`request.time.toMillis() > 1600000000000`

Math Functions

Function	Description	Example
`abs()`	Absolute value	`abs(-5) == 5`
`ceil()`	Round up	`ceil(4.2) == 5`
`floor()`	Round down	`floor(4.8) == 4`
`pow()`	Power	`pow(2, 3) == 8`
`round()`	Round to nearest	`round(4.6) == 5`
`sqrt()`	Square root	`sqrt(16) == 4`

Indexing and Slicing

Operation	Example
Access element	`request.resource.data.tags[0] == "chocolate"`
Slice list	`request.resource.data.tags[0:2] == ["chocolate", "chips"]`

Parent topic: Operators and Functions