Schema Metadata

The driver provides access to keyspace and table metadata. This schema metadata is monitored by the control conneciton and automatically kept up-to-date.

/* Create session */

/* Get snapshot of the schema */
const CassSchema* schema = cass_session_get_schema(session);

/* Get information about the "keyspace1" schema */
const CassSchemaMeta* keyspace1_meta
  = cass_schema_get_keyspace(schema, "keyspace1");

if (keyspace1_meta == NULL) {
  /* Handle error */
}

/* Get the key-value filed for "strategy_class" */
const CassSchemaMetaField* strategy_class_field
  = cass_schema_meta_get_field(keyspace1_meta, "strategy_class");

if (strategy_class_field == NULL) {
  /* Handle error */
}

/* Get the value part of the field */
const CassValue* strategy_class_value
  = cass_schema_meta_field_value(strategy_class_field);

/* Fields values use the existing cass_value*() API */
const char* strategy_class;
size_t strategy_class_length;
cass_value_get_string(strategy_class_value,
                      &strategy_class,
                      &strategy_class_length);

/* Do something with strategy_class */

/* All values derived from the schema are cleaned up */
cass_schema_free(schema);

The snapshot obtained by cass_session_get_schema() will not see schema changes that happened after the call. A new snapshot needs to be obtained to see subsequent updates to the schema.

Contents

Schema Metadata