CODEWITHSUNDEEP
javacassandradatastax-java-driver
niaomingjian
niaomingjian

Reputation: 3742

How to programmatically know the primary keys of a table in Cassandra

I'm using Datastax driver to access cassandra. My method takes a cql string paramater. Because the cql is arbitrary, I don't know the primary keys of the table in the cql string.

In ResultSet, I didn't find the metadata associated with the primary keys. I can only get the names and values of all columns.

I'd like to know which columns are primary keys. How to programmatically get the primary keys of the table in the cql?

public Map<String, Object> search(String cql) {

    SimpleStatement statement = new SimpleStatement(cql);
    ResultSet result = session.execute(statement);
    // ...
}

Upvotes: 0

Views: 1970

Answers (3)

Mindaugas K.
Mindaugas K.

Reputation: 498

with com.datastax.oss.driver.api.core.CqlSession;

getCqlSession().getMetadata().getKeyspace("my_keyspace").get().getTable("my_table").get().getPrimaryKey()

Upvotes: 0

Ashraful Islam
Ashraful Islam

Reputation: 12850

You can use TableMetadata.getPrimaryKey() method

Here is a sample demo to get the primary key of keyspace 'test' and table ashraful_test

try (Cluster cluster = Cluster.builder().addContactPoints("127.0.0.1").withCredentials("cassandra", "cassandra").build(); Session session = cluster.connect("test")) {
    System.out.println(cluster.getMetadata().getKeyspace(session.getLoggedKeyspace()).getTable("ashraful_test").getPrimaryKey());
}

Upvotes: 4

Marko Švaljek
Marko Švaljek

Reputation: 2101

I'm not aware of any driver stuff but if everything fails you can do following:

cqlsh> select column_name, kind from system_schema.columns where keyspace_name ='test' and table_name = 'authorization';

 column_name             | kind
-------------------------+---------------
 authorization_reference |       regular
            order_number | partition_key
              partner_id |    clustering
        sales_channel_id |    clustering

Upvotes: 2

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