QueryPredicate class

A predicate contains instructions for filtering rows when performing a Query.

Predicates currently are the WHERE clause in a SQL statement and are used verbatim by the PersistentStore. In general, you should use Query.where instead of using this class directly, as Query.where will use the underlying PersistentStore to generate a QueryPredicate for you.

A predicate has a format and parameters. The format is the String that comes after WHERE in a SQL query. The format may have parameterized values, for which the corresponding value is in the parameters map. A parameter is prefixed with '@' in the format string. Currently, the format string's parameter syntax is defined by the PersistentStore it is used on. An example of that format:

var predicate = new QueryPredicate("x = @xValue", {"xValue" : 5});

Constructors

QueryPredicate(String? format, Map<String, dynamic>? parameters)

Default constructor

QueryPredicate.and(Iterable<QueryPredicate?>? predicates)

Combines predicates with 'AND' keyword.

factory

QueryPredicate.empty()

Creates an empty predicate.

Properties

format ↔ String?

The string format of the this predicate.

getter/setter pair

hashCode → int

The hash code for this object.

no setter, inherited

parameters ↔ Map<String, dynamic>?

A map of values to replace in the format string at execution time.

getter/setter pair

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited