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 = const {}]) - Default constructor
-
QueryPredicate.and(Iterable<
QueryPredicate> predicates) -
Combines
predicateswith '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 setterinherited
-
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 setterinherited
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