I just started learning Cassandra any suggestion where to start with ??
Thanks Soumya On Thu, Sep 13, 2012 at 10:54 AM, Roshni Rajagopal < roshni_rajago...@hotmail.com> wrote: > I want to learn how we can model a mix of static and dynamic columns in > a family. > > Consider a course_students col family which gives a list of students for a > course > with row key- Course Id > Columns - Name, Teach_Nm, StudID1, StudID2, StudID3 > Values - Maths, Prof. Abc, 20,21,25 > where 20,21,25 are IDs of students. > > We have > > fixed columns like Course Name, Teacher Name, and a dynamic number of > > columns like 'StudID1', 'StudID2' etc, and my thoughts were that we could > > look for 'StudID' and get all the columns with the student Ids in Hector. > But the > > question was how would we determine the number for the column, like to add > > StudID3 we need to read the row and identify that 2 students are there, > > and this is the third one. > > > So we can remove the number in the column name, altogether and keep > > columns like Course Name, Teacher Name, Student:20,Student:21, Student:25, > > where the second part is the actual student id. However here we run into > > the second issue that we cannot have some columns of a composite format > > and some of another format, when we use static column families- all > > columns would need to be in the format UTF8:integer We may want to treat > > it as a composite column key and not use a delimiter- to get sorting, > > validate the types of the parts of the key, not have to search for the > > delimiter and separate the 2 components manually etc. > > > A third option is to put only data in the column name for students like > > Course Name, Teacher Name, 20,21,25 - it would be difficult to identify > > that columns with name 20, 21, 25 actually stand for student names - a bit > > unreadable. > > > I hope this is not confusing, and would like to hear your thoughts on this.The > question is > > around when you de-normalize & want to have some static info like name , > > and a dynamic list - whats the best way to model this. > > > Regards, > > Roshni > -- Regards and Thanks Soumya Kanti Acharya
