EOKeyValueQualifier
- Inherits from:
- EOQualifier : NSObject
- Conforms to:
- EOQualifierEvaluation
- EOQualifierSQLGeneration
Declared in:
- EOControl/EOQualifier.h
Class Description
EOKeyValueQualifier is a subclass of EOQualifier that compares
a named property of an object with a supplied value, for example,
"salary > 1500". EOKeyValueQualifier adopts the EOQualifierEvaluation protocol,
which defines the method evaluateWithObject: for
in-memory evaluation. When an EOKeyValueQualifier object receives
an evaluateWithObject: message,
it evaluates the given object to determine if it satisfies the qualifier
criteria.
In addition to performing in-memory filtering, EOKeyValueQualifier can be used to generate SQL. When it's used for this purpose, the key should be a valid property name of the root entity for the qualifier (or a valid key path).
Adopted Protocols
EOQualifierEvaluation
- - evaluateWithObject:
EOQualifierSQLGeneration
- - sqlStringForSQLExpression:
- - schemaBasedQualifierWithRootEntity:
Instance Methods
evaluateWithObject
- (BOOL)evaluateWithObject:anObject
initWithKey:operatorSelector:value:
- initWithKey:(NSString
*)key operatorSelector:(SEL)selector
value:(id)value
Initializes the receiver to compare values for key to value using the operator selector selector. The possible values for selector are as follows:
- EOQualifierOperatorEqual
- EOQualifierOperatorNotEqual
- EOQualifierOperatorLessThan
- EOQualifierOperatorGreaterThan
- EOQualifierOperatorLessThanOrEqualTo
- EOQualifierOperatorGreaterThanOrEqualTo
- EOQualifierOperatorContains
- EOQualifierOperatorLike
- EOQualifierOperatorCaseInsensitiveLike
Enterprise Objects Framework supports SQL generation for these selectors only.
For example, the following excerpt creates an EOKeyValueQualifier qual that has the key "name", the operator selector EOQualifierOperatorEqual, and the value "Smith". Once constructed, the qualifier qual is used to filter an in-memory array.
NSArray *employees; /* Assume this exists. */ EOQualifier *qual = [[EOKeyValueQualifier alloc] initWithKey:@"name" operatorSelector:EOQualifierOperatorEqual value:@"Smith"]; return [employees filteredArrayUsingQualifier:qual];
key
- (NSString *)key
selector
- (SEL)selector
value
- (id)value