Schema Metadata
Ruby Driver allows inspecting schema metadata
Background
- Given
- a running cassandra cluster
Getting keyspace metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster ks_meta = cluster.keyspace('simplex') puts "Name: #{ks_meta.name}" puts "Replication class: #{ks_meta.replication.klass}" puts "Replication factor: #{ks_meta.replication.options['replication_factor'].to_i}" puts "Durable writes?: #{ks_meta.durable_writes?}" puts "# tables: #{ks_meta.tables.size}" puts "" puts ks_meta.to_cql
- When
- it is executed
- Then
- its output should contain:
Name: simplex Replication class: SimpleStrategy Replication factor: 3 Durable writes?: true # tables: 0 CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '3'} AND durable_writes = true;
Getting table metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TABLE simplex.users (user_id bigint, first text, last text, age int, PRIMARY KEY (user_id, last))
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster table_meta = cluster.keyspace('simplex').table('users') puts "Name: #{table_meta.name}" puts "Keyspace: #{table_meta.keyspace.name}" puts "Partition key: #{table_meta.partition_key[0].name}" puts "Clustering column: #{table_meta.clustering_columns[0].name}" puts "Clustering order: #{table_meta.clustering_order.first}" puts "Num columns: #{table_meta.columns.size}" puts "" puts table_meta.to_cql
- When
- it is executed
- Then
- its output should contain:
Name: users Keyspace: simplex Partition key: user_id Clustering column: last Clustering order: asc Num columns: 4 CREATE TABLE simplex."users" ( user_id bigint, last text, age int, first text, PRIMARY KEY (user_id, last) )
Getting trigger metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TABLE simplex.test_table (a text primary key, b text); CREATE TABLE simplex.audit (key timeuuid, keyspace_name text, table_name text, primary_key text, PRIMARY KEY(key)); CREATE TRIGGER trigger1 ON simplex.test_table USING 'org.apache.cassandra.triggers.AuditTrigger';
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster # AuditTrigger is available in cassandra/conf/triggers. See cassandra/examples/triggers in Cassandra trigger = cluster.keyspace('simplex').table('test_table').trigger('trigger1') puts trigger.to_cql puts "" puts "Name: #{trigger.name}" puts "Table name: #{trigger.table.name}" puts "Class: #{trigger.options['class']}"
- When
- it is executed
- Then
- its output should contain:
CREATE TRIGGER "trigger1" ON simplex.test_table USING 'org.apache.cassandra.triggers.AuditTrigger'; Name: trigger1 Table name: test_table Class: org.apache.cassandra.triggers.AuditTrigger
Getting index metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TABLE simplex.test_table (a int primary key, b int); CREATE INDEX ind1 ON simplex.test_table (b);
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster index = cluster.keyspace('simplex').table('test_table').index('ind1') puts index.to_cql puts "" puts "Name: #{index.name}" puts "Table name: #{index.table.name}" puts "Kind: #{index.kind}" puts "Target: #{index.target}"
- When
- it is executed
- Then
- its output should contain:
CREATE INDEX "ind1" ON simplex.test_table (b); Name: ind1 Table name: test_table Kind: composites Target: b
since cassadra v3.0
Getting index metadata on full collections
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TABLE simplex.test_table (a int PRIMARY KEY, b frozen<map<text, text>>); CREATE INDEX ind1 ON simplex.test_table (full(b));
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster index = cluster.keyspace('simplex').table('test_table').index('ind1') puts index.to_cql puts "" puts "Name: #{index.name}" puts "Table name: #{index.table.name}" puts "Kind: #{index.kind}" puts "Target: #{index.target}"
- When
- it is executed
- Then
- its output should contain:
CREATE INDEX "ind1" ON simplex.test_table (full(b)); Name: ind1 Table name: test_table Kind: composites Target: full(b)
since cassadra v3.0
Getting multiple index metadata on same column
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TABLE simplex.test_table (a int PRIMARY KEY, b map<text, text>); CREATE INDEX ind1 ON simplex.test_table (keys(b)); CREATE INDEX ind2 ON simplex.test_table (values(b));
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster index = cluster.keyspace('simplex').table('test_table').index('ind1') puts index.to_cql puts "" puts "Name: #{index.name}" puts "Target: #{index.target}" puts "" index = cluster.keyspace('simplex').table('test_table').index('ind2') puts index.to_cql puts "" puts "Name: #{index.name}" puts "Target: #{index.target}"
- When
- it is executed
- Then
- its output should contain:
CREATE INDEX "ind1" ON simplex.test_table (keys(b)); Name: ind1 Target: keys(b) CREATE INDEX "ind2" ON simplex.test_table (values(b)); Name: ind2 Target: values(b)
since cassadra v2.1
Getting user-defined type metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TYPE simplex.address (street text, zipcode int); CREATE TYPE simplex.check_in ( location frozen <address>, time timestamp, data frozen <tuple<int, text, float>> ); CREATE TABLE simplex.users (id int PRIMARY KEY, location frozen<address>);
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster cluster.keyspace('simplex').each_type do |type| puts type.to_cql end
- When
- it is executed
- Then
- its output should contain:
CREATE TYPE simplex.address ( street text, zipcode int ); CREATE TYPE simplex.check_in ( location frozen <address>, time timestamp, data frozen <tuple<int, text, float>> );
since cassadra v2.2
Getting user-defined functions and metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE OR REPLACE FUNCTION simplex.fLog(input double) CALLED ON NULL INPUT RETURNS double LANGUAGE java AS 'return Double.valueOf(Math.log(input.doubleValue()));'
- And
- the following example:
require 'cassandra' include Cassandra::Types cluster = Cassandra.cluster puts cluster.keyspace('simplex').function('fLog', double).to_cql function = cluster.keyspace('simplex').function('fLog', double) puts "" puts "Name: #{function.name}" puts "Language: #{function.language}" puts "Return type: #{function.type}" puts "Called on null?: #{function.called_on_null?}" puts "Argument 'input'?: #{function.has_argument?("input")}" function.each_argument { |arg| puts "Argument type: #{arg.type}" }
- When
- it is executed
- Then
- its output should contain:
CREATE FUNCTION simplex.flog(input double) CALLED ON NULL INPUT RETURNS double LANGUAGE java AS $$return Double.valueOf(Math.log(input.doubleValue()));$$; Name: flog Language: java Return type: double Called on null?: true Argument 'input'?: true Argument type: double
since cassadra v2.2
Getting user-defined aggregates and metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE OR REPLACE FUNCTION simplex.avgState(state tuple<int, bigint>, val int) CALLED ON NULL INPUT RETURNS tuple<int, bigint> LANGUAGE java AS 'if (val !=null) { state.setInt(0, state.getInt(0)+1); state.setLong(1, state.getLong(1)+val.intValue()); } return state;'; CREATE OR REPLACE FUNCTION simplex.avgFinal(state tuple<int, bigint>) CALLED ON NULL INPUT RETURNS double LANGUAGE java AS 'double r = 0; if (state.getInt(0) == 0) return null; r = state.getLong(1); r/= state.getInt(0); return Double.valueOf(r);'; CREATE OR REPLACE AGGREGATE simplex.average(int) SFUNC avgState STYPE tuple<int, bigint> FINALFUNC avgFinal INITCOND (0, 0);
- And
- the following example:
require 'cassandra' include Cassandra::Types cluster = Cassandra.cluster aggregate = cluster.keyspace('simplex').aggregate('average', int) puts aggregate.to_cql puts "" puts "Name: #{aggregate.name}" puts "Return type: #{aggregate.type}" puts "Argument type: #{aggregate.argument_types[0].kind}" puts "State type: #{aggregate.state_type}" puts "Initial condition: #{aggregate.initial_state}" puts "State function: #{aggregate.state_function.name}" puts "Final function: #{aggregate.final_function.name}"
- When
- it is executed
- Then
- its output should contain:
CREATE AGGREGATE simplex.average(int) SFUNC avgstate STYPE tuple<int, bigint> FINALFUNC avgfinal INITCOND (0, 0); Name: average Return type: double Argument type: int State type: tuple<int, bigint> Initial condition: (0, 0) State function: avgstate Final function: avgfinal
since cassadra v3.0
Getting materialized view metadata
- Given
- the following schema:
CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}; CREATE TABLE simplex.test_table (f1 int PRIMARY KEY, f2 int, f3 int) ; CREATE MATERIALIZED VIEW simplex.test_view AS SELECT f1, f2 FROM simplex.test_table WHERE f2 IS NOT NULL PRIMARY KEY (f1, f2);
- And
- the following example:
require 'cassandra' cluster = Cassandra.cluster mv_meta = cluster.keyspace('simplex').materialized_view('test_view') puts "Name: #{mv_meta.name}" puts "Base table: #{mv_meta.base_table.name}" puts "Keyspace: #{mv_meta.keyspace.name}" puts "Partition key: #{mv_meta.partition_key[0].name}" puts "Clustering column: #{mv_meta.clustering_columns[0].name}" puts "Num columns: #{mv_meta.columns.size}" puts "" puts mv_meta.to_cql
- When
- it is executed
- Then
- its output should contain:
Name: test_view Base table: test_table Keyspace: simplex Partition key: f1 Clustering column: f2 Num columns: 2 CREATE MATERIALIZED VIEW simplex.test_view AS SELECT "f1", "f2" FROM simplex.test_table WHERE f2 IS NOT NULL PRIMARY KEY (("f1"), "f2") WITH bloom_filter_fp_chance = 0.01 AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'} AND comment = '' AND compaction = {'class': 'SizeTieredCompactionStrategy', 'max_threshold': '32', 'min_threshold': '4'} AND compression = {'chunk_length_in_kb': '64', 'class': 'LZ4Compressor'} AND crc_check_chance = 1.0 AND dclocal_read_repair_chance = 0.1 AND default_time_to_live = 0 AND gc_grace_seconds = 864000 AND max_index_interval = 2048 AND memtable_flush_period_in_ms = 0 AND min_index_interval = 128 AND read_repair_chance = 0.0 AND speculative_retry = '99PERCENTILE';