Operators and Functions

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

Operators

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

Logical Operators

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

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 || 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.

Built-in Functions

Oracle Backend with Firebase APIs 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"]`