Updating data in a linked table is not supported
This can be done using is used, the sorting is done using an external sort algorithm.In this case, each block of rows is sorted using quick sort, then written to disk; when reading the data, the blocks are merged together.To get the exclusive lock, other connection must not have any locks on the object.After the connection commits, all locks are released. When a lock is released, and multiple connections are waiting for it, one of them is picked at random.An exclusive lock is still used when adding or removing columns, when dropping the table, and when using .Connections only 'see' committed data, and own changes.If a connection cannot get a lock on an object, the connection waits for some amount of time (the lock timeout).During this time, hopefully the connection holding the lock commits and it is then possible to get the lock.
To make sure all connections only see consistent data, table level locking is used by default.If this is not possible because the other connection does not release the lock for some time, the unsuccessful connection will get a lock timeout exception.The lock timeout can be set individually for each connection.Please note that most data definition language (DDL) statements, such as "create table", commit the current transaction. Transaction isolation is provided for all data manipulation language (DML) statements.
Please note MVCC is enabled in version 1.4.x by default, when using the MVStore. Instead, rows are locked for update, and read committed is used in all cases (changing the isolation level has no effect).
This database supports linked tables, which means tables that don't exist in the current database but are just links to another database. If multiple linked tables point to the same database (using the same database URL), the connection is shared. The statement CREATE LINKED TABLE supports an optional schema name parameter.