How Do Developers Document Database Usages in Source Code?

Transcription

1 How Do Developers Document Database Usages in Source Code? Mario Linares-Vasquez, Boyang Li, Christopher Vendome, and Denys Poshyvanyk ASE 2015

2 Database-centric application (DCA) DCAs are software systems that rely on databases to persist records using database objects.

3 Database-centric application (DCA) DCAs are software systems that rely on databases to persist records using database objects.

4 Challenges

5 Challenges STUDENT ID Num PWD Gender Address Year DBManager.getAllInfoByStudentID ()

6 Challenges STUDENT ID Num PWD Gender Address Year DBManager.getAllInfoByStudentID () ID Num PWD ST_LOGIN ID Gender Address Year ST_DETAILS

7 Challenges STUDENT ID Num PWD Gender Address Year DBManager.getAllInfoByStudentID () ID Num PWD ID Gender Address Year getstlogin() getstdetails() ST_LOGIN ST_DETAILS

8 Challenges UI.student.buttonClickShowAllInfo() STUDENT ID Num PWD Gender Address Year UI.student.quaryAllInfoByID () DBManager.getAllInfoByStudentID () ID Num PWD ID Gender Address Year getstlogin() getstdetails() ST_LOGIN ST_DETAILS

9 Challenges How the model is described by a schema How the database is used in the source code

10 Related works

11 Related works

12 Related works

13 Related works No previous work has been done to understand database documentation practices at source code level.

14 Goal How Do Developers Document Database Usages in Source Code?

15 Methodology 381,161 projects

16 Methodology 381,161 projects Identified the projects using SQL 18,828 projects

17 Methodology 381,161 projects Identified the projects using SQL 18,828 projects 1 1 3,113 projects

18 Methodology A survey 3,113 projects A mining-based analysis

19 Methodology with A survey 147 developers 3,113 projects on A mining-based analysis 33,045 methods

20 Methodology with A survey 147 developers Results 3,113 projects on A mining-based analysis 33,045 methods Results

21 Research Questions RQ1. Do developers document database-related methods RQ2. Do developers update comments for database-related methods RQ3. How difficult is to understand the database schema constraints along call-chains

22 RQ1. Do developers comment methods in source code that locally execute SQL queries and statements? SQ1. Do you add/write documentation comments to methods in the source code? 25(17.01%) SQ2. Do you write source code comments detailing database schema constraints? 32(21.77%) 122(82.99%) Yes No 115(78.23%) Yes No

23 RQ1. Do developers comment methods in source code that locally execute SQL queries and statements? 32(21.77%) 115(78.23%) Yes No

24 RQ1. Do developers comment methods in source code that locally execute SQL queries and statements? 32(21.77%) The database schema and documentation takes care of that. I can always look at the table definition very easily. 115(78.23%) Yes No Comments related to the database schema and its constraints I consider to be irrelevant to the code using it. The schema, its details, and any quirks about it should be outlined in a separate document.

25 RQ1. Do developers comment methods in source code that locally execute SQL queries and statements? 32(21.77%) 7,595 (23%) 23% 115(78.23%) Yes No In the 3,113 projects, we identified a total of 33,045 methods invoking SQL ueries/statements.

26 RQ2. Do developers update comments of database-related methods during the evolution of a system? SQ3. How often do you find outdated comments in source code? SQ4. When you make changes to database related methods, how often do you update comments? 29(19.73%) 118(80.27%) Never Rarely Sometimes Fairly Often Always

27 RQ2. Do developers update comments of database-related methods during the evolution of a system? SQ3. How often do you find outdated comments in source code? SQ4. When you make changes to database related methods, how often do you update comments? 29(19.73%) 31(21.08%) 118(80.27%) Never Rarely Sometimes Fairly Often Always 116(78.92%) Never Rarely Sometimes Fairly Often Always

28 RQ2. Do developers update comments of database-related methods during the evolution of a system? 3,113 projects 264 projects 8.5% Had explicit releases

29 RQ2. Do developers update comments of database-related methods during the evolution of a system? 3,113 projects 264 projects 8.5% Had explicit releases 2,662 methods (Invoke SQL)

30 RQ2. Do developers update comments of database-related methods during the evolution of a system? 2,662 methods (Invoke SQL) 3,113 projects 8.5% Had explicit releases 23.2% were updated 618 methods 264 projects

31 RQ2. Do developers update comments of database-related methods during the evolution of a system? 2,662 methods (Invoke SQL) 3,113 projects 264 projects 8.5% Had explicit releases 618 methods 82.8% didn t updated comments 23.2% were updated 512 methods

32 RQ2. Do developers update comments of database-related methods during the evolution of a system? 2,662 methods (Invoke SQL) 3,113 projects 264 projects 8.5% Had explicit releases 82.8% didn t updated comments 23.2% were updated 618 methods 17.2% updated comments 512 methods 106 methods

33 RQ2. Do developers update comments of database-related methods during the evolution of a system? 106 methods (90%,100%] (80%,90%] (70%,80%] (60%,70%] (50%,60%] (40%,50%] (30%,40%] (20%,30%] (10%,20%] (0%,10%] frequency that the comments were updated when the method was modified

34 RQ2. Do developers update comments of database-related methods during the evolution of a system? 106 methods (90%,100%] 56 (80%,90%] 2 (70%,80%] (60%,70%] (37.73%) (50%,60%] 4 (40%,50%] 21 (30%,40%] 14 (20%,30%] 3 (10%,20%] 1 (0%,10%] frequency that the comments were updated when the method was modified

35 RQ3. How difficult is it for developers to understand propagated schema constraints along call-chains? SQ5. How difficult is it to trace the schema constraints (e.g., foreign key violations) from the methods with SQL statements to top-level method callers 50(34.01%) 97(65.99%) Very Easy Easy Moderate Hard Very Hard

36 Lessons learnt (i) Documenting database usages and constraints is not a common practice in source code methods (ii) Developers do not update comments when changes are done to database-related methods (iii) Tracing schema constraints through call-chains in the call graph is not an easy task in most of the cases

37 Lessons learnt (i) Documenting database usages and constraints is not a common practice in source code methods Documentation (ii) Developers do not update comments when changes are done to database-related methods Automation (iii) Tracing schema constraints through call-chains in the call graph is not an easy task in most of the cases Calling context

38 Summary

39 Summary

40 Summary

41 Summary