Hi, (Warning: I'm kind of a newbie...) I would make the tables as follows:
<table1: Single column (named 'c') to save space by avoiding the overhead by the key and multiple cells> row1: type1 + foo row2: type2 + bar row3: type1 + baz row4: type2 + whatever <index1: Again single column, and the data value is duplicated from table1. With this you can just Scan through the index1 to get the values, avoiding Gets to table1.> type1 + row1: foo type1 + row3: baz type2 + row2: bar type2 + row4: whatever <index2> Not needed Cheers. -----Original Message----- From: Wilm Schumacher [mailto:[email protected]] Sent: Saturday, January 17, 2015 6:23 AM To: [email protected] Subject: general question about datamodel => empty columns Hi, I run into a problem , which I encounter several times by now and perhaps you can help me. What should I include in tables where just the qualifier is needed? E.g. in indexing you have to make the reference of the index either by columns, or by rows in the index table. But in this way, there is no data to put into the table. An example for clarification: Suppose you want to make an index for another table which indexes something like "type of entry". <table> row1 data:type => type1 , data:data => foo row2 data:type => type2 , data:data => bar row3 data:type => type1 , data:data => baz row4 data:type => type2 , data:data => whatever indexing 1: indexing by columns <index> type1 index:row1 => ??? , index:row2 => ??? type2 index:row2 => ??? , index:row4 => ??? indexing 2: indexing by rows <index> type1-row1 ??:?? => ?? type1-row3 ??:?? => ?? type2-row2 ??:?? => ?? type2-row3 ??:?? => ?? works if there is any column family file to scan. Thus I need data. either way ... I actually have to put data where it is'n needed. What should I do to insert into the columns? By now I mostly use the timestamp of creation, which in my opinion is quite stupid, as I have the timestamp in the column right away. This only would waste space. I could use empty strings (bytes), which will work, but somehow feels wrong. What are you using? Is empty string/useless timestamp common practice? Best wishes, Wilm
