Schema introspection

Laravel's schema methods read ClickHouse connections:

use Illuminate\Support\Facades\Schema;

Schema::getTables();                            // Tables of the database of the connection
Schema::getTableListing();                      // ['default.my_table', ...]
Schema::getViews();                             // Views and materialized views
Schema::getColumns('my_table');
Schema::getColumnListing('my_table');           // ['id', 'created_at', ...]
Schema::hasColumn('my_table', 'field_one');     // true
Schema::hasColumns('my_table', ['id', 'field_one']); // true
Schema::getColumnType('my_table', 'field_one'); // 'String'
Schema::getIndexes('my_table');
Schema::getIndexListing('my_table');            // ['primary']
Schema::hasIndex('my_table', 'primary');        // true
Schema::getCurrentSchemaName();                 // 'default', the database of the connection
Schema::getCurrentSchemaListing();              // ['default']
Schema::hasTable('my_table');                   // true for a table, false for a view or a dictionary
Schema::hasView('my_view');                     // Views and materialized views
Schema::hasDictionary('my_dictionary');         // Dictionaries

To read another database, give its name, or a list of names, to getTables(), getTableListing() and getViews(). Give a <database>.<table> name to the other methods: Schema::getTables('analytics'), Schema::getColumns('analytics.events'). When ClickHouse is not the default connection, use Schema::connection('clickhouse').

Results

Method	Result
getTables()	The tables, with the database as schema, total_bytes as size, the comment and the engine. No views, materialized views, .inner tables or dictionaries. The size of a Merge table is NULL.
getViews()	The views and materialized views, with their SELECT as definition
hasTable()	true for a table only. Use hasView() for a view and hasDictionary() for a dictionary.
getColumns()	The full type, such as LowCardinality(Nullable(String)), as type and type_name. default is the DEFAULT or EPHEMERAL expression. MATERIALIZED columns have a stored generation. ALIAS columns have a virtual generation.
getIndexes()	The primary key, with the name primary, then the data-skipping indexes
getForeignKeys(), hasForeignKey()	[] and false. ClickHouse has no foreign keys.

• A column is nullable when its type accepts NULL: Nullable(...), LowCardinality(Nullable(...)), Variant(...), Dynamic, or a SimpleAggregateFunction over one of them. Array(Nullable(String)) is not nullable.
• The columns of an index are the parts of its expression: ORDER BY (id, intHash32(id)) gives ['id', 'intHash32(id)']. ORDER BY (id) gives ['id'] on all versions.
• The type of the primary key is null. The type of a data-skipping index is its type, such as minmax or bloom_filter. Index names are lowercase. No index is unique.
• Schema::disableForeignKeyConstraints(), enableForeignKeyConstraints() and withoutForeignKeyConstraints() send no query.

Artisan commands

php artisan db:show --database=clickhouse --counts --views
php artisan db:table my_table --database=clickhouse

• db:show shows the server version and the tables. --counts adds the row counts. --views adds the views.
• Open Connections are the client connections to the active node, which system.metrics counts. A user without access to the system tables gets an error.
• db:table shows the columns and indexes of one table. The primary key has the attribute primary, or compound, primary for many columns.
• --counts fails on a table that ClickHouse cannot read, such as Kafka or Set. --views fails on a parameterized view.