类似于执行单个语句提交或回滚事务也会触发警告。为了能够处理这些警告， 需要检查 Session.commit();or 的回复结果对象。Session.rollback();

这在以下示例中显示。该示例假定测试架构存在且集合 my_collection不存在。

MySQL 外壳 JavaScript 代码

var mysqlx = require('mysqlx');

// Connect to server
var mySession = mysqlx.getSession( {
        host: 'localhost', port: 33060,
        user: 'user', password: 'password' } );

// Get the Schema test
var myDb = mySession.getSchema('test');

// Create a new collection
var myColl = myDb.createCollection('my_collection');

// Start a transaction
mySession.startTransaction();
try
{
    myColl.add({'name': 'Rohit', 'age': 18, 'height': 1.76}).execute();
    myColl.add({'name': 'Misaki', 'age': 24, 'height': 1.65}).execute();
    myColl.add({'name': 'Leon', 'age': 39, 'height': 1.9}).execute();

    // Commit the transaction if everything went well
    var reply = mySession.commit();

    // handle warnings
    if (reply.warningCount){
      var warnings = reply.getWarnings();
      for (index in warnings){
        var warning = warnings[index];
        print ('Type ['+ warning.level + '] (Code ' + warning.code + '): ' + warning.message + '\n');
      }
    }

    print ('Data inserted successfully.');
}
catch(err)
{
    // Rollback the transaction in case of an error
    reply = mySession.rollback();

    // handle warnings
    if (reply.warningCount){
      var warnings = reply.getWarnings();
      for (index in warnings){
        var warning = warnings[index];
        print ('Type ['+ warning.level + '] (Code ' + warning.code + '): ' + warning.message + '\n');
      }
    }

    // Printing the error message
    print ('Data could not be inserted: ' + err.message);
}

MySQL 外壳 Python 代码

from mysqlsh import mysqlx

# Connect to server
mySession = mysqlx.get_session( {
        'host': 'localhost', 'port': 33060,
        'user': 'user', 'password': 'password' } )

# Get the Schema test
myDb = mySession.get_schema('test')

# Create a new collection
myColl = myDb.create_collection('my_collection')

# Start a transaction
mySession.start_transaction()
try:
    myColl.add({'name': 'Rohit', 'age': 18, 'height': 1.76}).execute()
    myColl.add({'name': 'Misaki', 'age': 24, 'height': 1.65}).execute()
    myColl.add({'name': 'Leon', 'age': 39, 'height': 1.9}).execute()

    # Commit the transaction if everything went well
    reply = mySession.commit()

    # handle warnings
    if reply.warning_count:
      for warning in result.get_warnings():
        print('Type [%s] (Code %s): %s\n' % (warning.level, warning.code, warning.message))

    print('Data inserted successfully.')
except Exception as err:
    # Rollback the transaction in case of an error
    reply = mySession.rollback()

    # handle warnings
    if reply.warning_count:
      for warning in result.get_warnings():
        print('Type [%s] (Code %s): %s\n' % (warning.level, warning.code, warning.message))

    # Printing the error message
    print('Data could not be inserted: %s' % str(err))

C#代码

// Connect to server
var session = MySQLX.GetSession("server=localhost;port=33060;user=user;password=password;");

// Get the Schema test
var db = session.GetSchema("test");

// Create a new collection
var myColl = db.CreateCollection("my_collection");

// Start a transaction
session.StartTransaction();
int warningCount = 0;
try
{
	var result = myColl.Add(new { name = "Rohit", age = 18, height = 1.76}).Execute();
	warningCount += result.Warnings.Count;
	result = myColl.Add(new { name = "Misaki", age = 24, height = 1.65}).Execute();
	warningCount += result.Warnings.Count;
	result = myColl.Add(new { name = "Leon", age = 39, height = 1.9}).Execute();
	warningCount += result.Warnings.Count;

	// Commit the transaction if everything went well
	session.Commit();
	if(warningCount > 0)
	{
	  // handle warnings
	}

	Console.WriteLine("Data inserted successfully.");
}
catch (Exception err)
{
	// Rollback the transaction in case of an error
	session.Rollback();
	if(warningCount > 0)
	{
	  // handle warnings
	}

	// Printing the error message
	Console.WriteLine("Data could not be inserted: " + err.Message);
}

Python代码

import mysqlx

# Connect to server
my_session = mysqlx.get_session({
    'host': 'localhost', 'port': 33060,
    'user': 'user', 'password': 'password'
})

# Get the Schema test
my_schema = my_session.get_schema('test')

# Create a new collection
my_coll = my_schema.create_collection('my_collection')

# Start a transaction
my_session.start_transaction()
try:
    my_coll.add({'name': 'Rohit', 'age': 18, 'height': 1.76}).execute()
    my_coll.add({'name': 'Misaki', 'age': 24, 'height': 1.65}).execute()
    my_coll.add({'name': 'Leon', 'age': 39, 'height': 1.9}).execute()

    # Commit the transaction if everything went well
    result = my_session.commit()

    # handle warnings
    if result.get_warnings_count() > 0:
        for warning in result.get_warnings():
            print('Type [{0}] (Code {1}): {2}'.format(warning['level'], warning['code'], warning['msg']))

    print('Data inserted successfully.')
except Exception as err:
    # Rollback the transaction in case of an error
    result = my_session.rollback()

    # handle warnings
    if result.get_warnings_count() > 0:
        for warning in result.get_warnings():
            print('Type [{0}] (Code {1}): {2}'.format(warning['level'], warning['code'], warning['msg']))

    # Printing the error message
    print('Data could not be inserted: {0}'.format(err))

Java代码

// c.f. "standard transaction handling"

C++代码

/*
  Connector/C++ does not yet provide access to transaction warnings
  -- Session methods commit() and rollback() do not return a result object.
*/

默认情况下，所有警告都从服务器发送到客户端。如果已知某个操作会生成许多警告并且这些警告对应用程序没有价值，则可以抑制发送警告。这有助于节省带宽。 session.setFetchWarnings()控制警告是在服务器上丢弃还是发送到客户端。 session.getFetchWarnings()用于了解当前活动的设置。

MySQL 外壳 JavaScript 代码

var mysqlx = require('mysqlx');

function process_warnings(result){
  if (result.getWarningCount()){
    var warnings = result.getWarnings();
    for (index in warnings){
      var warning = warnings[index];
      print ('Type ['+ warning.level + '] (Code ' + warning.code + '): ' + warning.message + '\n');
    }
  }
  else{
    print ("No warnings were returned.\n");
  }
}

// Connect to server
var mySession = mysqlx.getSession( {
  host: 'localhost', port: 33060,
  user: 'user', password: 'password' } );

// Disables warning generation
mySession.setFetchWarnings(false);
var result = mySession.sql('drop schema if exists unexisting').execute();
process_warnings(result);

// Enables warning generation
mySession.setFetchWarnings(true);
var result = mySession.sql('drop schema if exists unexisting').execute();
process_warnings(result);

MySQL 外壳 Python 代码

from mysqlsh import mysqlx

def process_warnings(result):
  if result.get_warnings_count():
    for warning in result.get_warnings():
      print('Type [%s] (Code %s): %s\n' % (warning.level, warning.code, warning.message))
  else:
    print("No warnings were returned.\n")


# Connect to server
mySession = mysqlx.get_session( {
  'host': 'localhost', 'port': 33060,
  'user': 'user', 'password': 'password' } );

# Disables warning generation
mySession.set_fetch_warnings(False)
result = mySession.sql('drop schema if exists unexisting').execute()
process_warnings(result)

# Enables warning generation
mySession.set_fetch_warnings(True)
result = mySession.sql('drop schema if exists unexisting').execute()
process_warnings(result)

Java代码

// Connect to server
Session mySession = new SessionFactory().getSession("mysqlx://localhost:33060/test?user=user&password=password");

Schema db = mySession.getSchema("test");

// Create a new collection
Collection myColl = db.createCollection("my_collection");

// Start a transaction
mySession.startTransaction();
try {
    Result res = myColl.add("{\"name\":\"Rohit\", \"age\":18}", "{\"name\":\"Misaki\", \"age\":24}", "{\"name\":\"Leon\", \"age\":39}").execute();

    System.out.println(res.getWarningsCount());

    Iterator<Warning> warnings = res.getWarnings();
    while (warnings.hasNext()) {
        Warning warn = warnings.next();
        System.out.println(warn.getCode() + ", " + warn.getLevel() + ", " + warn.getMessage());
    }

    mySession.commit();
    System.out.println("Data inserted successfully.");
} catch (Exception err) {
    // Rollback the transaction in case of an error
    mySession.rollback();

    // Printing the error message
    System.out.println("Data could not be inserted: " + err.getMessage());
}