← Databases

Apache Cassandra and ScyllaDB

One driver, built on the scylla crate (with rustls), speaks CQL over the native protocol to both. The server says which it is, and the connection shows it. The driver is part of the app; nothing is downloaded. The editor takes CQL.

Connect

The default port is 9042. The Host field is a contact point, or several host:port pairs separated by commas. The Keyspace field (optional) is the keyspace the session starts in; the navigator lists all of them either way.

• One contact point, or a tunnel: that node alone serves every statement. A cluster advertises its nodes' own addresses, which a container, a NAT or a tunnel hides, so the driver does not follow them. With several contact points the driver is given all of them and may use any.
• Signing in: a user and password, for the server's password authenticator. Without a user the connection is anonymous.
• TLS: CQL cannot negotiate it, so TLS is on for cassandras:// and scyllas:// URLs and for SSL modes from require up; prefer is plain. require does not check the certificate; verify-ca and verify-full do. A CA file and a client certificate go in the TLS fields.
• Statements have no timeout of the driver's own: one runs until it finishes or you cancel.

Privileges

The navigator reads system_schema, which Cassandra 3 and later and ScyllaDB share; the login sees what the server lets it read there. There are no administration tabs. Writes need the permissions CQL asks for.

What works

• CQL scripts, split by the editor ($$ … $$ strings, // comments and a BEGIN BATCH … APPLY BATCH are understood), with typed results read page by page as you scroll, using the server's paging state.
• The navigator: keyspaces as schemas, tables, materialized views, user-defined types, functions and aggregates, with each table's partition and clustering keys and its indexes; the DDL of each object.
• The grid edits rows, by the full primary key (partition and clustering columns): an edited row is an UPDATE, a new row an INSERT that needs every key column, a deleted row a DELETE. The preview shows the statements, which run one after the other; one the server refuses stops the rest. Undo script puts the old values back. Key columns cannot be changed (delete the row and insert another), and counters are refused.
• Lightweight transactions (IF …) are reported as such with their outcome.
• Cancel stops a result being read. Errors keep the server's message.
• USE keyspace changes the session's keyspace, which the driver keeps.

What does not

• No transactions: every statement takes effect on its own, and there is no manual commit.
• CQL writes are upserts and report no row count, so a statement that returns no rows reports none changed; an update of a row somebody deleted meanwhile writes it again.
• The data viewer has no filter and sort bar, and shows no row count.
• No explain, and no SQL tools: no table editor, ER diagram, schema comparison, query builder, SQL import, snapshots before changes, or terminal mode (cqlsh takes the password only on its command line).

Agents

run_query and sample_rows (a CQL SELECT … LIMIT n) work; a statement that changes data is asked about first. Refused on Cassandra: explain and propose_edits; estimate_change answers with a note. See Agents and the CLI.

Known limits

• Cassandra older than 4.0 and ScyllaDB older than 5.4 are refused when connecting, with "older than … the oldest version supported", unlike the other databases, which connect with a warning.
• No joins, no OFFSET, and rows are found only by their primary key, as CQL has it.

Tested on

The conformance suite runs on Apache Cassandra 5 and ScyllaDB 2025.1, without login: server info, scripts, every type as a typed column, paging, lightweight transactions, errors, cancel, the catalog and its DDL (also functions and aggregates), saving the grid's changes and undoing them, a wrong or missing login being refused, and a tunnel address. Cassandra 4.0 and ScyllaDB 5.4 are the lowest versions the driver accepts and are not run by the suite.

See also: Connecting, Troubleshooting.