// 1. create an default database:
CrystManager *db = [CrystManager defaultCrystDB];

// 2. create an database with the name of `Person`:
CrystManager *db = [[CrystManager alloc] initWithName:@"Person"];

// Person Model
@interface Person : NSObject <CrystDB>
@property (nonatomic,assign) UInt64 uid;
@property (nonatomic,copy) NSString *name;
@property (nonatomic,assign) NSInteger age;
@end
@implementation Person
@end

// 0. Create an Person object:
Person *p =  [[Person alloc] init];
p.uid = 8082;
p.name = @"Ares";
p.age = 27;

// 1. Add an object，if there have been the object，then update the object:
BOOL result = [db addOrUpdateObject:p];

// 2. Add an object, if there have benn the object, then return with no processing:
BOOL result = [db addOrIgnoreObject:p];

// 3. If the object is already in the database and the object also have implemented the method of `CrystDBPrimaryKey`, then you can update the object directly(otherwise it's recommended to use `addOrUpdateObject：` method instead):
BOOL result = [db updateObject:p];

// 4. Use Transaction:
[db inTransaction:^(BOOL * _Nonnull rollback) {
   BOOL result = [db addOrUpdateObject:p];
   if (result == NO) {
      *rollback = YES;
   }
}];  

// 1. Query objects with the Class of this object:
NSArray *persons = [db queryWithClass:[Person class] condition:nil];

// 2. Query objects with conditions:
NSArray *persons = [db queryWithClass:[Person class] condition:@"age > 25 or name == 'Ares' "];

// 3. Query objects with format conditions:
NSArray *persons = [db queryWithClass:[Person class] conditions:@"age > %d or name == '%@' ",25,@"Ares"];

// 4. Query with sql sentence syntax:
NSArray *persons = [db queryWithClass:[Person class] where:@"age > 8082" orderBy:@"uid desc" limit:@"1,10"];

// 1. Delete objects with conditions:
BOOL result = [db deleteClass:[Person class] where:@"name = 'Ares' "];

// 2. Delete all the object related to the class:
BOOL result = [db dropClass:[Person class]];

// 3. Delete all the objects in this database:
BOOL result = [db dropAll];

// 4. Delete the object which implement the method of `CrystDBPrimaryKey` and the object has the vlaue of primary key, otherwise it will fail:
BOOL result = [db deleteObject:p];

// 1. Specify the primary key
+ (NSString *)CrystDBPrimaryKey{
    return @"uid";
}

// 2. Appoint the default database of this object
+ (NSString *)CrystDBName{
    return @"child.db";
}

// 3. Set the property whitelist of this object
+ (NSArray<NSString *> *)CrystDBWhitelistProperties{
    return @[@"uid"，@"name"，@"age"];
}

// 4. Set the property blacklist of this object
+ (NSArray<NSString *> *)CrystDBBlacklistProperties{
    return @[@"age"];
}

// 5. If the object has parent class which have properties involved
+ (BOOL)CrystDBObjectIsHasSuperClass{
    return YES;
}

// 6. If there are objects nested in this object, it needs to implement the Coding method, or it's strongly recommended to use `CSModel` to implement the following method:
- (void)encodeWithCoder:(NSCoder *)aCoder{
    [self cs_encode:aCoder];
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder{
    return [self cs_decoder:aDecoder];
}

// 1. Add an object，if there have been the object，then update the object:
BOOL result = [p cs_addOrUpdateToDB];

// 2. Add an object with no processing if there have benn the object:
BOOL result = [p cs_addOrIgnoreToDB];

// 3. Query objects with conditions:
Person *p = [Person cs_queryObjectsWithCondition:@"age > 25"];

// 4. Query the object by primary key which must implement the `CrystDBPrimaryKey` method:
Person *p = [Person cs_queryObjectOnPrimary:@"8082"];

// 5. Query the number of all the objects:
NSInteger count = [Person cs_queryObjectCount];

// 6. Query the create time of an object:
NSInteger createTime = [p cs_queryObjectCreateTime];

// 7. Query the update time of an object:
NSInteger updateTime = [p cs_queryObjectUpdateTime];

// 8. Delete objects with the conditions:
[Person cs_deleteFromDBWithCondition:@"name = 'Ares' "];

// 9. Delete all the objects in the database:
BOOL result = [p cs_deleteFromDB];
  
// 10. Execute the transaction in a block
[Person cs_inTransaction:^(CrystDB *db, BOOL *rollback) {
   BOOL result = [db addOrUpdateObject:p];
   if (result == NO) {
      *rollback = YES;
    }
}];