Cassandra Table structure/Terminology
- Before going to learn CQL commands, we just need to know terminology in cassandra.
|Primary key||Row Key|
|Column name||Column name|
|Column value||column value|
Creating a key-space
Use the keyspace (will use that key space)
Note: key spaces are equivalent to database/schema in RDBMS
Get list of key spaces
Get list of tables in a key-space
Insert data into table
Update data in table
Delete data in table
Limitations in CQL
- Delete query without where condition will not work.
- Delete/Update query with Non-primary key in where clause will not works.
- To use Select query with Non-primary key in where clause, we should index that column.
- Instead of Update we can use insert with same primary key value, will replace the existing record with new values. (Upsert)
we cannot use ‘or’ clause in cql instead we have to use ‘in’ clause.
Java client example
- Take a Java maven project and Add below dependency
- Below shows the Sample Java client example