In my earlier posts on NSPredicate, We have discussed,
In this part, let's see some Relational operations along with compound predicates.
- IN
- ALL
- ANY
- SOME
- NONE
We have already covered IN operation in Part 3/4. To discuss remaining Relational operations, let's take another data set.
Let's say fetching all the departments in an organization given the below JSON response.
{
"name" : "Banking",
"employees" : [
{
"name" : "Tim",
"salary" : 45000
},
{
"name" : "Smith",
"salary" : 19000
},
{
"name" : "George",
"salary" : 30000
}
]
},
{
"name" : "Healthcare",
"employees" : [
{
"name" : "Martin",
"salary" : 45000
},
{
"name" : "Smith",
"salary" : 56000
},
{
"name" : "Anderson",
"salary" : 24000
}
]
},
{
"name" : "Mobility",
"employees" : [
{
"name" : "Martin",
"salary" : 45000
},
{
"name" : "Smith",
"salary" : 17000
},
{
"name" : "Anderson",
"salary" : 24000
}
]
}
]
This response is in array format and it is having all the departments with their name and employees set.
Let's start our filtration without which we can't live :)
#1 Filter the departments having employee salary less than 20000
Technically, We need all the departments having any of the employee's salary less than 20000.
NSPredicate *predicate = [NSPredicate predicateWithFormat:
@"ANY employees.salary < %d",20000];
NSArray *filteredArr = [arrDepartments filteredArrayUsingPredicate:predicate];
NSLog(@"filteredArr : %@",filteredArr);
filteredArr : (
{
employees = (
{
name = Tim;
salary = 45000;
},
{
name = Smith;
salary = 19000;
},
{
name = George;
salary = 30000;
}
);
name = Banking;
},
{
employees = (
{
name = Martin;
salary = 32000;
},
{
name = Smith;
salary = 17000;
},
{
name = Anderson;
salary = 24000;
}
);
name = Mobility;
}
)
#2 Filter the departments having all the employees salary greater than 20000
NSPredicate *predicate = [NSPredicate predicateWithFormat:
@"ALL employees.salary > %d",20000];
NSArray *filteredArr = [arrDepartments filteredArrayUsingPredicate:predicate];
NSLog(@"filteredArr : %@",filteredArr);
filteredArr : (
{
employees = (
{
name = Martin;
salary = 45000;
},
{
name = Smith;
salary = 56000;
},
{
name = Anderson;
salary = 24000;
}
);
name = Healthcare;
}
)
#3 Filter the departments having none of the employees salary less then 20000
NSPredicate *predicate = [NSPredicate predicateWithFormat:
@"NONE employees.salary < %d",20000];
NSArray *filteredArr = [arrDepartments filteredArrayUsingPredicate:predicate];
NSLog(@"filteredArr : %@",filteredArr);
filteredArr : (
{
employees = (
{
name = Martin;
salary = 45000;
},
{
name = Smith;
salary = 56000;
},
{
name = Anderson;
salary = 24000;
}
);
name = Healthcare;
}
)
Hope this post is useful. Feel free to comment in case of any queries.
