## April 20, 2014

### How to Facilitate Relational Reference: Generic, Sequence, and Table Sequence

Based on the generic data type, esProc provides the sequence and the Table Sequence for implementing the complete set-lizing and the much more convenient relational queries.

The relation between the department and the employee is one-to-many and that between the employee and the SSN (Social Security Number) is one-to-one. Everything is related to everything else in the world. The relational query is the access to relational dataset with the mathematical linguistics. Thanks to the associated query, the relational database (RDBMS) is extensively adopted.
I Case and Comparison
Case
There is a telecommunications enterprise that needs to perform this analysis: to find out the annual outstanding employees whose line manager having been awarded the president honor. The data are from two tables: the first is the department table mainly consisting of deptName and manager fields; and the second is the employee table mainly consisting of the empName, empHonor, and empDept fields;

For empHonor, three kinds of values can be obtained: First, null value; Second, ”president's award” and PA for short; Third, ”employee of the year” and EOY for short; The corresponding relations are usually belong to either of the two below groups: empDept & deptName, and Manager & empName.

SQL Solution
SELECT A.*
FROM employee A,department B,employee C
WHERE A.empDept=B.deptName AND B.manager=C.empName AND A.empHonor=‘EOY’ AND C.empHornor=‘PA’

Complex SQL JOIN query can be used to solve such problems. In this case, we choose the nested query that is brief and clear. The association statements after “where” have established one-to-many relation between deptName and empDept, and the one-to-one relation between manager and empName.

esProc Solution
employee.select(empHonor:"EOY",empDept.manager.empHornor:"PA")

The esProc solution is quite intuitive: select the employees with EOY on condition that the line respective managers of these employees have won the “PA”.

Comparison
Regarding the SQL solution, the SQL statements is lengthy and not intuitive. Actually, the complete associated query statement is “inner join…on…”. We have put it in a rather simplified way or the statements would be even harder to comprehend.

Regarding the esProc solution, the esProc fields are of generic type, which can point to any data and dataset. Therefore, you can simply use ”.” symbol to access the associated table directly. By representing in such intuitive and easy-to-understand way, esProc users can convert the complicated and lengthy SQL statement for multiple table association to the simple object access. This is unachievable if using SQL.

II Function Description:
Generic Data Type

The data in esProc are all of generic type, that is, the data types are not strictly distinguished. Therefore, a data can be a simple data like “1” or “PA” ,or a set like [1,” PA”], or a set composed of sets like the database records.
Sequence

A sequence is a data structure specially designed for the mass data analysis. It is similar to the concept of “array + set” in the senior language. That is to say, esProc users can assess members of any type according to its serial number, and perform the intersection, union, and complementary set operations on these members. The sequence is characterized with two outstanding features: generic type, and being ordered.

For example, let’s suppose that the sequence A is a set of line managers, and the sequence B is a set of award-winning employees. Then, the award-winning departments can be computed as a result of A^B. The top three departments can be obtained as a result of [1,2,3] (Please refer to other documents for the characteristics of being ordered).

esProc provides a great many of easy-to-use functions for sequence. The analysis will be greatly simplified if you grasped the use of sequence well.
Table Sequence
The Table Sequence is a sequence of database structure. As a sequence, it is characterized by being generic and ordered. In addition, Table Sequence also inherited the concept of database table that allows for the access to data with the field and the record.

The characteristics of generic type allow for the associated query in a quite convenient way in which the access to the record of associated table is just like the access to object. For example, to access the line manager of a certain employee, you can just compose “empDept.manager”. By comparison, the counterpart SQL syntax requires quite lots of wieldy association statements: “from…where…” or “left outer/right outer/inner join…on…”

Moreover, the characteristics of being ordered are quite useful and convenient for solving the tough computational problems relating to the Table Sequence and serial numbers, such as computing the top N, year-on-year statistics, and link relative ratio analysis.
The Access Syntax to Convert Complexity to Simplicity
esProc users can use ”.” to access the record in the associated table. Compared with the lengthy and complicated association syntax of SQL, such access method and style is much easier.

Intuitive Analysis is Ideal for Business Specialist
Analyzing from the business aspect, the business specialist can reach the result more correctly and rapidly. esProc users can access to the associated data in an intuitive way following the business descriptions and thus it is ideal for business specialist.

Easy to Analyze and Solve Problem
The sequence and table sequence of esProc is fit for processing the mass data. Even for the complicated multiple-table association, esProc users can solve the problems conveniently in the process of data analysis.