Patent Document

PRIORITY CLAIM 
     This application is a continuation of U.S. patent application Ser. No. 11/693,305, U.S. Pat. No. 7,680,766 filed Mar. 29, 2007, the contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to data management and more particularly relates to a method and apparatus for adding a database partition. 
     BACKGROUND OF THE INVENTION 
     Increased reliance on computers and networks has likewise increased the need for high-availability and scalability of such computers and networks. One specific example is wireless telecommunications. In a wireless telecommunication network, the network must be available twenty-four hours a day, creating the need for maintenance and upgrades to be performed while the network is running “hot”, and with minimal disruption in quality of service. As new services and/or subscribers are continuously added to the network, existing database hardware will eventually need to be replaced and upgraded. Data from existing hardware must then be migrated to the new hardware, again with minimal disruption in quality of service. 
     SUMMARY OF THE INVENTION 
     An aspect of the specification provides a method for adding a database partition comprising: 
     determining an existing number of partitions; 
     examining each existing partition to determine which portion of each existing partition is to be transferred according to a minimally progressive hash operation; 
     adding a new partition; and, 
     transitioning portions of existing partitions to said new partition according to the determinations made during said examining step. 
     The hashing operation is selected from a class of partitioning algorithms that substantially maintain a maximum, or substantially maximum, consistency between consecutive partition sizes. 
     The method can be repeated until a desired number of partitions have been added. 
     Another aspect of the specification provides a computer readable medium that stores programming instructions that implements the method. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a data repository system in accordance with an embodiment. 
         FIG. 2  shows a flowchart depicting a method of adding a database partition. 
         FIG. 3  shows a representation of the addition of a database partition to the system of  FIG. 1  using the method in  FIG. 2 . 
         FIG. 4  is a graph showing the data that needs to be moved during performance of the method in  FIG. 2  using a particular hashing operation. 
         FIGS. 5A and 5B  show the data in  FIG. 4  in tabular format. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring now to  FIG. 1 , a data repository system is indicated generally at  50 . In a present embodiment, system  50  is presented in the context of a wireless telecommunications system, but it is to be understood that system  50  can be varied to other contexts. System  50  comprises a plurality of service control points (“SCPs”)  54 - 1 ,  54 - 2  (collectively, SCPs  54 , and generically, SCP  54 .). SCPs  54  are connected, via a network N- 1 , to a plurality of applications  58 - 1 ,  58 - 2  (collectively, applications  58 , and generically, application  58 ). Applications  58  are, in turn, are serviced, via a second network N- 2 , by one or more primary databases  62 P which in turn can be backed-up by one or more secondary databases  62 S service data points. (Collectively, databases  62  and generically, databases  62 ). However, those skilled in the art will recognize that secondary databases  62 S can be omitted altogether. Those skilled in the art will also now recognize that applications  58  and databases  62  can be collectively referred to as service data points (SDPs). While the present embodiment, includes specific reference to network N- 1  and SCPs  54 , it will become apparent that network N- 1  and SCPs  54  can be omitted altogether, or SCPs can simply be any type of client machine that is accessing applications  58 . Networks N- 1  and N- 2  are comprised of any network infrastructure components that are used to implement desired physically interconnections, and can, in fact be implemented on a single network. In the present embodiment, network N- 1  is implemented via SS7 network infrastructure, whereas network N- 2  is implemented via a local area network or a wide area network based on Internet protocols. 
     Applications  58  can be any type of application that is currently known (or is developed in the future) that would serve data stored in databases  62  to SCPs  54 . A well known example of an application  58  is an application to route 1-800-numbers to a traditional area code and phone number. Other examples for applications  58  include customer resource management, cross-service bundling, location services and rating, Virtual Private Networking, Prepaid billing, Missed Call Return, Loyalty Reward and Promotion Programs, Fraud Management, Policy Management, Call Screening and Redirection, and Subscriber Profile Management. 
     Databases  62  include the infrastructure to store, retrieve and manage data, including hardware to store the data and a database application layer, such as the Structured Query Language (“SQL”) or the like, to interface between each database  62  and each application  58 . 
     Referring now to  FIG. 2  a method for adding a database partition is represented in a flowchart indicated generally at  100 . Method  100  can be performed on a variety of different systems, but in order to assist in explanation of system  50  and method  100 , it will be assumed that method  100  is performed using system  50 . 
     In the present embodiment, database  62 P- 1  represents a single partition and that database  62 S- 1  represents a single partition. Thus, to give a concrete example of the performance of method  100 , it will be assumed that database partition  62 P- 1  is full and that a second database partition  62 P- 2  is being added to database partition  62 P- 1 . Method  100  can be implemented on any suitable computing environment (e.g. a server) with physical connections to each database partition  62 P in order to examine the existing partitions  62 P and determine how to move data on the existing partition(s) to the new partition.  FIG. 3  shows a representation of method  100 , drawn as an oval, operating on database partition  62 P- 1  so as to add database partition  62 P- 2 . (Though not shown, method  100  would likewise apply to the addition of a second database partition to database partition  62 S- 1 ). 
     Beginning at step  105  in  FIG. 2 , a determination is made as to the existing number of partitions. In the present example, it is determined that only one database partition  62 P- 1  currently exists. Next, at step  110 , each existing partition is examined to determine which portion of each existing partition is to be transitioned to the new partition according to a minimally progressive hashing operation. The minimally progressive hashing operation is represented as an oval indicated at “H” in  FIG. 3 . In the present example, database partition  62 P- 1  would be examined and, assuming database partition  62 P- 1  was full, then hashing operation H would determine that half of the data thereon would be identified as a candidate for moving to new partition  62 P- 2 . Hashing operation H would likewise identify which exact portions would be candidates for moving. 
     Next, at step  115 , the new partition would be added. In the present example database partition  62 P- 2  would become physically and operationally attached to and integrated with partition  62 P- 1 , such that each application  58  would perceive both partitions  62 P- 1  and  62 P- 2  to be a single database  62 P, such that each application  58  would continue to interact with partitions  62 P in the same manner as one partition  62 P. 
     Next, at step  115 , the new partition would be added. In the present example database partition  62 P- 2  would become physically attached to partition  62 P- 1 . Next, at step  120 , portions of the existing database will be ported from the existing partition(s) to the new partition in accordance with the determinations made by hashing operation H at step  110 . At the conclusion of performance of step  120 , application  58  would perceive both partitions  62 P- 1  and  62 P- 2  to be a single database  62 P, such that each application  58  would continue to interact with partitions  62 P in the same manner as one partition  62 P. 
     It is contemplated that during the performance of steps  115  and  120 , each application  58  will be able to access database  62 P in such a manner that, where an application  58  expects to find data on the second database partition  62 P- 2  as it would expect to find such data at the conclusion of the performance of step  120 , then that application  58  will initially look for that data on the second database partition  62 P- 2 , and, where that data is not found, then that application  58  will look for that data on the first database partition  62 P- 1 . An exemplary mechanism for accomplishing this is as follows: Application  58  first attempts to find the data as though the migration to database  62 P- 2  had already been completed. If the data is not found by application  58  then application  58  would try to find the data again, but instead using the same method that application  58  used before database  62 P- 2  were added. A more sophisticated mechanism can be made aware of the progress of the data migration to database  62 P- 2  so that application  58  would know whether a particular piece of data had been migrated, or not. 
     It will now be understood that method  100  can be used to add any number of partitions (not shown in the Figures) to database partitions  62 P- 1  and  62 P- 2 , or to database  62 B. It should also be understood that hashing operation H can be implemented in a variety of ways. Hashing operation H can be selected from a class of partitioning algorithms that share the unusual property that they substantially maintain a maximum, or substantially maximum, consistency between consecutive partition sizes. An example of one hashing operation H is provided in Appendix I in the form of pseudo-code and referred to as hashing operation H- 1 . 
     Table I shows the progression of movement of data as method  100  is performed eight times, each time adding a new partition, using hashing operation H- 1 , so that at the conclusion database  62 P has a total of nine partitions referred to herein as  62 P- 1 ,  62 P- 2 , . . .  62 P- 9 . In Table I, the term “Key” refers to the index or other pointer that identifies each portion of the database partition. Thus, each partition in the example of Table I has nineteen portions. It will be understood, however, that in other embodiments each partition can be divided into other portion sizes. The partition number beside each key indicates the location of the portion of data associated with that corresponding Key. Each “*” indicates that the portion corresponding to the * was moved during the previous performance of method  100  by hashing operation H- 1 . 
     
       
         
               
             
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                 Results of performing method 100 nine 
               
               
                 times using hashing operation H-1 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Zero performances of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 1 
               
               
                   
                 (Only Partition 62P-1) 
               
               
                   
                 Key10: Partition 62P-1 
               
               
                   
                 Key11: Partition 62P-1 
               
               
                   
                 Key12: Partition 62P-1 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-1 
               
               
                   
                 Key15: Partition 62P-1 
               
               
                   
                 Key16: Partition 62P-1 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-1 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-1 
               
               
                   
                 Key21: Partition 62P-1 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-1 
               
               
                   
                 Key24: Partition 62P-1 
               
               
                   
                 Key25: Partition 62P-1 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-1 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-1 
               
               
                   
                 First performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 2 
               
               
                   
                 (Partition 62P-2 is added) 
               
               
                   
                 Key10: Partition 62P-2 * 
               
               
                   
                 Key11: Partition 62P-1 
               
               
                   
                 Key12: Partition 62P-2 * 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 * 
               
               
                   
                 Key15: Partition 62P-1 
               
               
                   
                 Key16: Partition 62P-2 * 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-2 * 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-1 
               
               
                   
                 Key21: Partition 62P-2 * 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-2 * 
               
               
                   
                 Key24: Partition 62P-1 
               
               
                   
                 Key25: Partition 62P-2 * 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-2 * 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 * 
               
               
                   
                 Second performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 3 
               
               
                   
                 (Partition 62P-3 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-1 
               
               
                   
                 Key12: Partition 62P-3 * 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 * 
               
               
                   
                 Key16: Partition 62P-2 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-3 * 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-1 
               
               
                   
                 Key21: Partition 62P-3 * 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-2 
               
               
                   
                 Key24: Partition 62P-3 * 
               
               
                   
                 Key25: Partition 62P-2 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-3 * 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                 Third performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 4 
               
               
                   
                 (Partition 62P-4 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-1 
               
               
                   
                 Key12: Partition 62P-4 * 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 
               
               
                   
                 Key16: Partition 62P-4 * 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-3 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-1 
               
               
                   
                 Key21: Partition 62P-3 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-4 * 
               
               
                   
                 Key24: Partition 62P-3 
               
               
                   
                 Key25: Partition 62P-2 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-4 * 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                 Fourth performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 5 
               
               
                   
                 (Partition 62P-5 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-5 * 
               
               
                   
                 Key12: Partition 62P-4 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 
               
               
                   
                 Key16: Partition 62P-5 * 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-3 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-5 * 
               
               
                   
                 Key21: Partition 62P-3 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-4 
               
               
                   
                 Key24: Partition 62P-3 
               
               
                   
                 Key25: Partition 62P-5 * 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-4 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                 Fifth performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 6 
               
               
                   
                 (Partition 62P-6 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-5 
               
               
                   
                 Key12: Partition 62P-6 * 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 
               
               
                   
                 Key16: Partition 62P-5 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-6 * 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-5 
               
               
                   
                 Key21: Partition 62P-6 * 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-4 
               
               
                   
                 Key24: Partition 62P-3 
               
               
                   
                 Key25: Partition 62P-5 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-6 * 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                 Sixth performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 7 
               
               
                   
                 (Partition 62P-7 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-7 * 
               
               
                   
                 Key12: Partition 62P-6 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 
               
               
                   
                 Key16: Partition 62P-5 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-7 * 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-5 
               
               
                   
                 Key21: Partition 62P-6 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-4 
               
               
                   
                 Key24: Partition 62P-3 
               
               
                   
                 Key25: Partition 62P-7 * 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-6 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                 Seventh performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 8 
               
               
                   
                 (Partition 62P-8 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-7 
               
               
                   
                 Key12: Partition 62P-8 * 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 
               
               
                   
                 Key16: Partition 62P-5 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-7 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-5 
               
               
                   
                 Key21: Partition 62P-6 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-8 * 
               
               
                   
                 Key24: Partition 62P-3 
               
               
                   
                 Key25: Partition 62P-7 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-6 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                 Eighth performance of 
               
               
                   
                 method 100 
               
               
                   
                 Partition Size: 9 
               
               
                   
                 (Partition 62P-9 is added) 
               
               
                   
                 Key10: Partition 62P-2 
               
               
                   
                 Key11: Partition 62P-7 
               
               
                   
                 Key12: Partition 62P-9 * 
               
               
                   
                 Key13: Partition 62P-1 
               
               
                   
                 Key14: Partition 62P-2 
               
               
                   
                 Key15: Partition 62P-3 
               
               
                   
                 Key16: Partition 62P-5 
               
               
                   
                 Key17: Partition 62P-1 
               
               
                   
                 Key18: Partition 62P-7 
               
               
                   
                 Key19: Partition 62P-1 
               
               
                   
                 Key20: Partition 62P-5 
               
               
                   
                 Key21: Partition 62P-6 
               
               
                   
                 Key22: Partition 62P-1 
               
               
                   
                 Key23: Partition 62P-8 
               
               
                   
                 Key24: Partition 62P-3 
               
               
                   
                 Key25: Partition 62P-7 
               
               
                   
                 Key26: Partition 62P-1 
               
               
                   
                 Key27: Partition 62P-9 * 
               
               
                   
                 Key28: Partition 62P-1 
               
               
                   
                 Key29: Partition 62P-2 
               
               
                   
                   
               
             
          
         
       
     
     Another example of a hashing operation H is provided in Appendix 2 and referred to as hashing operation H- 2 . 
       FIG. 4  shows the progression of movement of data as method  100  is performed using hashing operation H- 2 , so that at the conclusion database  62 P has a total of eighteen partitions. Each row in  FIG. 4  represents a key. Each column represents the addition of a new partition. Squares in a given row indicate that the data represented by this row need to be transitioned to a new partition as part of the migration caused by adding the new node represented by the corresponding column. The first column is solid because all data needed to be written into the first partition. Moving across a row shows at which partition size increases a particular piece of data needed to be moved to the new partition. Reading down a row shows which keys were copied into the new partition when the new partition was created.  FIGS. 5A and 5B  are another representation of  FIG. 4 , except that  FIGS. 5A and 5B  also show to which partition each key is allocated at each point in time. 
     Varieties of permutations, combinations, variations and/or subsets of the embodiments discussed herein are contemplated and will now occur to those skilled in the art. For example, system  50  can be varied for environments other than telecommunications, in which case databases  62  that serve applications  58 , can in turn service any type of client machine, and not just SCPs  54 . 
     
       
         
               
             
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
             
               
               
             
               
             
           
               
                 APPENDIX I 
               
               
                   
               
               
                 Pseudo-code for hashing operation H-1 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 define function part(hash, 1) −&gt; (1, hash) 
               
               
                 define function part(hash, size) −&gt; (partition, remainder) as 
               
             
          
           
               
                   
                 let (partition, remainder) = part (hash, size−1) 
               
               
                   
                 if remainder mod size = 0 then 
               
             
          
           
               
                   
                 return (size, remainder / size) 
               
             
          
           
               
                   
                 else 
               
             
          
           
               
                   
                 return (partition, remainder * (size−1) / size) 
               
             
          
           
               
                   
                 end 
               
             
          
           
               
                 end function 
               
               
                 define function part(key) −&gt; partition 
               
             
          
           
               
                   
                 return part(hashValueOf(key), current_partition_size) end function 
               
             
          
           
               
                 The second ‘part’ function above is limited by the growth of the 
               
               
                 ‘factorial’ function. As such, it can only be used for partition sizes 
               
               
                 up to 20. 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
             
               
               
               
             
               
             
               
               
             
               
               
             
               
             
               
               
             
               
               
             
               
             
           
               
                 APPENDIX II 
               
               
                   
               
               
                 Pseudo-code for hashing operation H-2 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 A more complicated version is listed below which instead relies of the 
               
               
                 LCM (lowest common multiple) instead of the factorial. As a result 
               
               
                 hashing operation H-2 is suitable for partition sizes of up to 42. 
               
               
                 define function part(hash, size) −&gt; (partition, remainder) as 
               
             
          
           
               
                   
                 let (partition, remainder) = 
                 part(hash, size−1) 
               
               
                   
                 let new_LCM = 
                 lcm(1..size) 
               
               
                   
                 let old_LCM = 
                 lcm(1..size−1) 
               
               
                   
                 let number_per_old = 
                 new_LCM / size 
               
               
                   
                 let steals_per_old = 
                 number per old / (size−1) 
               
               
                   
                 let cycle = 
                 remainder / (new_LCM / (size−1)) 
               
               
                   
                 let cycle_remainder = 
                 remainder mod (new_LCM / (size−1)) 
               
               
                   
                 let cycle_steal = 
                 max(0, 1 + cycle_remainder − 
               
             
          
           
               
                 number_per_old) 
               
             
          
           
               
                   
                 if cycle_steal &gt; 0 then 
               
             
          
           
               
                   
                 return (size, (partition − 1) * steals_per_old + 
               
             
          
           
               
                 cycle_steal − 1 + cycle * number_per_old) 
               
             
          
           
               
                   
                 else 
               
               
                   
                 return (partition, cycle * number_per_old + cycle_remainder) 
               
             
          
           
               
                   
                 end 
               
             
          
           
               
                 end function 
               
               
                 Examples: 
               
               
                 part(“john smith”,5) −&gt; 3 
               
               
                 part(“sue smith”, 5) −&gt; 2 
               
               
                 part(“555-1234”, 20) −&gt; 15 
               
               
                 part(“555-2345”, 20) −&gt; 4

Technology Category: 4