large table
Posted in 2004
Hi , This is related to datawarehouse , data mining . We are told that data mining tools such as spss or sas , need a large table which has lots of columns inside . Based on our project , out final table which will be used in data mining , has lots of computed values . The final number of columns of the table is 7800!(lots of calculated values) First of all , i dont see the reason of this requirement of the data mining tools. I will be appreciated if someone can clarify this: Why does a data mining tool need such a large table? The main issue is if i create table with 7800 columns inside ( in fact oracle only allows to create table with 1000 columns) , i believe it cant be queried. My basic calculation shows that the average row size of this table will be 160kb. , considering my db_block_size of 16kb. this means 10 blocks for 1 row. (The table will have more than 10.000.000 rows) No matter how fast my disk subsystem is , i think the queries against this table will fail. So what can i do? May be I need a different type of storage technique for instance column based storage ( i heard that sysbase has this feature , dont know the details / purpose..) How can i solve such a problem? The database server really does not matter , it can be oracle,sqlserver , sybase,informix , etc... I will be appreciated if someone can help me abut the issue. Kind Regards, hope