MySQL Connector/C++ Release Notes
A session now can acquire a lock for documents or rows returned by find or select statements, to prevent the returned values from being changed from other sessions while the lock is held (provided that appropriate isolation levels are used). Locks can be requested several times for a given find or select statement. Only the final request is acted upon. An acquired lock is held until the end of the current transaction.
For X DevAPI, CollectionFind
and
TableSelect
implement
.lockExclusive()
and
.lockShared()
methods, which request
exclusive or shared locks, respectively, on returned documents
or rows. These methods can be called after
.bind()
and before the final
.execute()
.
For X DevAPI for C, the new
mysqlx_set_locking(
function can be
called to request exclusive or shared locks on returned
documents or rows, or to release locks. The
stmt
,
lock
)lock
parameter can be
ROW_LOCK_EXCLUSIVE
,
ROW_LOCK_SHARED
, or
ROW_LOCK_NONE
. The first two values specify a
type of lock to be acquired. ROW_LOCK_NONE
removes any row locking request from the statement.
(WL #10980)
For X DevAPI, a new auth
option can be
specified in connection strings or URIs to indicate the
authentication mechanism. Permitted values are
PLAIN
and MYSQL41
. The
option name and value are not case sensitive. The
SessionSettings::Options
object supports a
new AUTH
enumeration, with the same permitted
values.
For X DevAPI for C, a new auth
setting can be
specified in connection strings or URIs to indicate the
authentication mechanism. Permitted values are
PLAIN
and MYSQL41
. The
option name and value are not case sensitive. A new
MYSQLX_OPT_AUTH
constant is recognized by the
mysqlx_options_set()
function, with permitted
values MYSQLX_AUTH_PLAIN
and
MYSQLX_AUTH_MYSQL41
.
If the authentication mechanism is not specified, it defaults to
PLAIN
for secure (TLS) connections, or
MYSQL41
for insecure connections. For Unix
socket connections, the default is PLAIN
.
(WL #10718)
Boolean expressions used in queries and statements now support a
variant of the IN
operator for which the
right hand side operand is any expression that evaluates to an
array or document.
X DevAPI example:
coll.find("'car' IN $.toys").execute();
X DevAPI for C example:
res = mysqlx_collection_find(coll, "'car' IN $.toys");
In this form, the IN
operator is equivalent
to the JSON_CONTAINS()
SQL
function.
(WL #10979)
On Unix and Unix-like systems, Unix domain socket files are now supported as a connection transport for X DevAPI or X DevAPI for C connections. The socket file can be given in a connection string or in the session creation options.
X DevAPI examples:
XSession sess("mysqlx://user:password@(/path/to/mysql.sock)/schema"); XSession sess({ SessionSettings::USER, "user", SessionSettings::PWD, "password, SessionSettings::SOCKET, "/path/to/mysql.sock" SessionSettings::DB, "schema" });
X DevAPI for C examples:
mysqlx_session_t *sess = mysqlx_get_session_from_url( "mysqlx://user:password@(/path/to/mysql.sock)/schema", err_buf, &err_code ); mysqlx_opt_type_t *sess_opt = mysqlx_session_option_new(); mysqlx_session_option_set(sess_opt, MYSQLX_OPT_SOCKET, "/path/to/mysql.sock", MYSQLX_OPT_USER, "user", MYSQLX_OPT_PWD, "password", MYSQLX_OPT_DB, "schema"); mysqlx_session_t *sess = mysqlx_get_session_from_options( sess_opt, err_buf, &err_code );
(WL #9953)
These drop API changes were made:
Session::dropTable(
and
schema
,
table
)Session::dropCollection(
were replaced by
schema
,
coll
)Schema::dropTable(
and
table
)Schema::dropCollection(
,
respectively.
coll
)
Schema::dropView()
is now a
direct-execute method returning void
rather than Executable
.
All drop
methods succeed if the dropped objects do not exist.
XXX
()
(WL #10787)
The following Collection
methods were added:
addOrReplaceOne()
,
getOne()
, replaceOne()
,
and removeOne()
.
The addOrReplaceOne()
and
replaceOne()
methods work only with MySQL
8.0.3 and higher servers. For older servers, they report an
error.
(WL #10981)