DATABASE FUNDAMENTALS
BASICS OF BIG DATA
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Alter
|
|
|
update
|
|
|
delete
|
|
|
scan
|
Detailed explanation-1: -Alter is the command used to make changes to an existing table. Using this command, you can change the maximum number of cells of a column family, set and delete table scope operators, and delete a column family from a table.
Detailed explanation-2: -A column family cannot be renamed. The common approach to rename a family is to create a new family with the desired name and copy the data over, using the API. Reference Hbase-The Definitve Guide.
Detailed explanation-3: -Simply press the “+” button in the “Alter table” page and add your new column family with all settings you need.
Detailed explanation-4: -What is the best practice on deciding the number of column families for HBase table? Ans. Since every column family in HBase is stored as a single file, it is ideal not to exceed the number of columns families per HBase table by 15.