Reactive MSSQL Client
The Reactive MSSQL Client is a client for Microsoft SQL Server with a straightforward API focusing on scalability and low overhead.
Features
-
Event driven
-
Lightweight
-
Built-in connection pooling
-
Direct memory to object without unnecessary copies
-
Java 8 Date and Time
Not supported yet
-
Prepared queries caching
-
Batch and cursor
-
Row streaming
-
Some data types are not supported
Usage
To use the Reactive MSSQL Client add the following dependency to the dependencies section of your build descriptor:
-
Maven (in your
pom.xml
):
<dependency>
<groupId>io.vertx</groupId>
<artifactId>vertx-mssql-client</artifactId>
<version>4.1.0</version>
</dependency>
-
Gradle (in your
build.gradle
file):
dependencies {
compile 'io.vertx:vertx-mssql-client:4.1.0'
}
Getting started
Here is the simplest way to connect, query and disconnect
MSSQLConnectOptions connectOptions = new MSSQLConnectOptions()
.setPort(1433)
.setHost("the-host")
.setDatabase("the-db")
.setUser("user")
.setPassword("secret");
// Pool options
PoolOptions poolOptions = new PoolOptions()
.setMaxSize(5);
// Create the client pool
MSSQLPool client = MSSQLPool.pool(connectOptions, poolOptions);
// A simple query
client
.query("SELECT * FROM users WHERE id='julien'")
.execute(ar -> {
if (ar.succeeded()) {
RowSet result = ar.result();
System.out.println("Got " + result.size() + " rows ");
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
// Now close the pool
client.close();
});
Connecting to SQL Server
Most of the time you will use a pool to connect to MSSQL:
MSSQLConnectOptions connectOptions = new MSSQLConnectOptions()
.setPort(1433)
.setHost("the-host")
.setDatabase("the-db")
.setUser("user")
.setPassword("secret");
// Pool options
PoolOptions poolOptions = new PoolOptions()
.setMaxSize(5);
// Create the pooled client
MSSQLPool client = MSSQLPool.pool(connectOptions, poolOptions);
The pooled client uses a connection pool and any operation will borrow a connection from the pool to execute the operation and release it to the pool.
If you are running with Vert.x you can pass it your Vertx instance:
MSSQLConnectOptions connectOptions = new MSSQLConnectOptions()
.setPort(1433)
.setHost("the-host")
.setDatabase("the-db")
.setUser("user")
.setPassword("secret");
// Pool options
PoolOptions poolOptions = new PoolOptions()
.setMaxSize(5);
// Create the pooled client
MSSQLPool client = MSSQLPool.pool(vertx, connectOptions, poolOptions);
You need to release the pool when you don’t need it anymore:
pool.close();
When you need to execute several operations on the same connection, you need to use a client
connection
.
You can easily get one from the pool:
MSSQLConnectOptions connectOptions = new MSSQLConnectOptions()
.setPort(1433)
.setHost("the-host")
.setDatabase("the-db")
.setUser("user")
.setPassword("secret");
// Pool options
PoolOptions poolOptions = new PoolOptions()
.setMaxSize(5);
// Create the pooled client
MSSQLPool client = MSSQLPool.pool(vertx, connectOptions, poolOptions);
// Get a connection from the pool
client.getConnection().compose(conn -> {
System.out.println("Got a connection from the pool");
// All operations execute on the same connection
return conn
.query("SELECT * FROM users WHERE id='julien'")
.execute()
.compose(res -> conn
.query("SELECT * FROM users WHERE id='emad'")
.execute())
.onComplete(ar -> {
// Release the connection to the pool
conn.close();
});
}).onComplete(ar -> {
if (ar.succeeded()) {
System.out.println("Done");
} else {
System.out.println("Something went wrong " + ar.cause().getMessage());
}
});
Once you are done with the connection you must close it to release it to the pool, so it can be reused.
Configuration
Data Object
A simple way to configure the client is to specify a MSSQLConnectOptions
data object.
MSSQLConnectOptions connectOptions = new MSSQLConnectOptions()
.setPort(1433)
.setHost("the-host")
.setDatabase("the-db")
.setUser("user")
.setPassword("secret");
// Pool Options
PoolOptions poolOptions = new PoolOptions().setMaxSize(5);
// Create the pool from the data object
MSSQLPool pool = MSSQLPool.pool(vertx, connectOptions, poolOptions);
pool.getConnection(ar -> {
// Handling your connection
});
Connection URI
As an alternative to configuring the client with a MSSQLConnectOptions
data object, you can use a connection URI:
String connectionUri = "sqlserver://dbuser:[email protected]:3211/mydb";
// Create the pool from the connection URI
MSSQLPool pool = MSSQLPool.pool(connectionUri);
// Create the connection from the connection URI
MSSQLConnection.connect(vertx, connectionUri, res -> {
// Handling your connection
});
The connection URI format is defined by the client in an idiomatic way: sqlserver://[user[:[password]]@]host[:port][/database][?attribute1=value1&attribute2=value2…]
Currently, the client supports the following parameter keywords in connection uri (keys are case-insensitive):
-
host
-
port
-
user
-
password
-
database
Connect retries
You can configure the client to retry when a connection fails to be established.
options
.setReconnectAttempts(2)
.setReconnectInterval(1000);
Running queries
When you don’t need a transaction or run single queries, you can run queries directly on the pool; the pool will use one of its connection to run the query and return the result to you.
Here is how to run simple queries:
client
.query("SELECT * FROM users WHERE id='julien'")
.execute(ar -> {
if (ar.succeeded()) {
RowSet<Row> result = ar.result();
System.out.println("Got " + result.size() + " rows ");
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
Prepared queries
You can do the same with prepared queries.
The SQL string can refer to parameters by position, using the database syntax `@1`, `@2`, etc…
client
.preparedQuery("SELECT * FROM users WHERE [email protected]")
.execute(Tuple.of("julien"), ar -> {
if (ar.succeeded()) {
RowSet<Row> rows = ar.result();
System.out.println("Got " + rows.size() + " rows ");
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
Query methods provides an asynchronous RowSet
instance that works for SELECT queries
client
.preparedQuery("SELECT first_name, last_name FROM users")
.execute(ar -> {
if (ar.succeeded()) {
RowSet<Row> rows = ar.result();
for (Row row : rows) {
System.out.println("User " + row.getString(0) + " " + row.getString(1));
}
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
or UPDATE/INSERT queries:
client
.preparedQuery("INSERT INTO users (first_name, last_name) VALUES (@p1, @p2)")
.execute(Tuple.of("Julien", "Viet"), ar -> {
if (ar.succeeded()) {
RowSet<Row> rows = ar.result();
System.out.println(rows.rowCount());
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
The Row
gives you access to your data by index
System.out.println("User " + row.getString(0) + " " + row.getString(1));
or by name
System.out.println("User " + row.getString("first_name") + " " + row.getString("last_name"));
The client will not do any magic here and the column name is identified with the name in the table regardless of how your SQL text is.
You can access a wide variety of of types
String firstName = row.getString("first_name");
Boolean male = row.getBoolean("male");
Integer age = row.getInteger("age");
You can use cached prepared statements to execute one-shot prepared queries:
connectOptions.setCachePreparedStatements(true);
client
.preparedQuery("SELECT * FROM users WHERE id = @p1")
.execute(Tuple.of("julien"), ar -> {
if (ar.succeeded()) {
RowSet<Row> rows = ar.result();
System.out.println("Got " + rows.size() + " rows ");
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
You can create a PreparedStatement
and manage the lifecycle by yourself.
sqlConnection
.prepare("SELECT * FROM users WHERE id = @p1", ar -> {
if (ar.succeeded()) {
PreparedStatement preparedStatement = ar.result();
preparedStatement.query()
.execute(Tuple.of("julien"), ar2 -> {
if (ar2.succeeded()) {
RowSet<Row> rows = ar2.result();
System.out.println("Got " + rows.size() + " rows ");
preparedStatement.close();
} else {
System.out.println("Failure: " + ar2.cause().getMessage());
}
});
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
Using connections
Getting a connection
When you need to execute sequential queries (without a transaction), you can create a new connection or borrow one from the pool. Remember that between acquiring the connection from the pool and returning it to the pool, you should take care of the connection because it might be closed by the server for some reason such as an idle time out.
pool
.getConnection()
.compose(connection ->
connection
.preparedQuery("INSERT INTO Users (first_name,last_name) VALUES (@p1, @p2)")
.executeBatch(Arrays.asList(
Tuple.of("Julien", "Viet"),
Tuple.of("Emad", "Alblueshi")
))
.compose(res -> connection
// Do something with rows
.query("SELECT COUNT(*) FROM Users")
.execute()
.map(rows -> rows.iterator().next().getInteger(0)))
// Return the connection to the pool
.eventually(v -> connection.close())
).onSuccess(count -> {
System.out.println("Insert users, now the number of users is " + count);
});
Prepared queries can be created:
connection
.prepare("SELECT * FROM users WHERE first_name LIKE @p1")
.compose(pq ->
pq.query()
.execute(Tuple.of("Julien"))
.eventually(v -> pq.close())
).onSuccess(rows -> {
// All rows
});
Simplified connection API
When you use a pool, you can call withConnection
to pass it a function executed
within a connection.
It borrows a connection from the pool and calls the function with this connection.
The function must return a future of an arbitrary result.
After the future completes, the connection is returned to the pool and the overall result is provided.
pool.withConnection(connection ->
connection
.preparedQuery("INSERT INTO Users (first_name,last_name) VALUES (@p1, @p2)")
.executeBatch(Arrays.asList(
Tuple.of("Julien", "Viet"),
Tuple.of("Emad", "Alblueshi")
))
.compose(res -> connection
// Do something with rows
.query("SELECT COUNT(*) FROM Users")
.execute()
.map(rows -> rows.iterator().next().getInteger(0)))
).onSuccess(count -> {
System.out.println("Insert users, now the number of users is " + count);
});
Using transactions
Transactions with connections
You can execute transaction using SQL BEGIN
/COMMIT
/ROLLBACK
, if you do so you must use
a SqlConnection
and manage it yourself.
Or you can use the transaction API of SqlConnection
:
pool.getConnection()
// Transaction must use a connection
.onSuccess(conn -> {
// Begin the transaction
conn.begin()
.compose(tx -> conn
// Various statements
.query("INSERT INTO Users (first_name,last_name) VALUES ('Julien','Viet')")
.execute()
.compose(res2 -> conn
.query("INSERT INTO Users (first_name,last_name) VALUES ('Emad','Alblueshi')")
.execute())
// Commit the transaction
.compose(res3 -> tx.commit()))
// Return the connection to the pool
.eventually(v -> conn.close())
.onSuccess(v -> System.out.println("Transaction succeeded"))
.onFailure(err -> System.out.println("Transaction failed: " + err.getMessage()));
});
When the database server reports the current transaction is failed (e.g the infamous current transaction is aborted, commands ignored until
end of transaction block), the transaction is rollbacked and the completion
future
is failed with a TransactionRollbackException
:
tx.completion()
.onFailure(err -> {
System.out.println("Transaction failed => rolled back");
});
Simplified transaction API
When you use a pool, you can call withTransaction
to pass it a function executed
within a transaction.
It borrows a connection from the pool, begins the transaction and calls the function with a client executing all operations in the scope of this transaction.
The function must return a future of an arbitrary result:
-
when the future succeeds the client will commit the transaction
-
when the future fails the client will rollback the transaction
After the transaction completes, the connection is returned to the pool and the overall result is provided.
pool.withTransaction(client -> client
.query("INSERT INTO Users (first_name,last_name) VALUES ('Julien','Viet')")
.execute()
.flatMap(res -> client
.query("INSERT INTO Users (first_name,last_name) VALUES ('Julien','Viet')")
.execute()
// Map to a message result
.map("Users inserted")))
.onSuccess(v -> System.out.println("Transaction succeeded"))
.onFailure(err -> System.out.println("Transaction failed: " + err.getMessage()));
Tracing queries
The SQL client can trace query execution when Vert.x has tracing enabled.
The client reports the following client spans:
-
Query
operation name -
tags
-
db.user
: the database username -
db.instance
: the database instance -
db.statement
: the SQL query -
db.type
: sql
The default tracing policy is PROPAGATE
, the client
will only create a span when involved in an active trace.
You can change the client policy with setTracingPolicy
,
e.g you can set ALWAYS
to always report
a span:
options.setTracingPolicy(TracingPolicy.ALWAYS);
Data types supported
Currently, the client supports the following SQL Server types:
-
TINYINT(
java.lang.Short
) -
SMALLINT(
java.lang.Short
) -
INT(
java.lang.Integer
) -
BIGINT(
java.lang.Long
) -
BIT(
java.lang.Boolean
) -
REAL(
java.lang.Float
) -
DOUBLE(
java.lang.Double
) -
NUMERIC/DECIMAL(
BigDecimal
) -
CHAR/VARCHAR(
java.lang.String
) -
NCHAR/NVARCHAR(
java.lang.String
) -
DATE(
java.time.LocalDate
) -
TIME(
java.time.LocalTime
) -
DATETIME2(
java.time.LocalDateTime
) -
DATETIMEOFFSET(
java.time.OffsetDateTime
) -
BINARY/VARBINARY(
io.vertx.core.buffer.Buffer
)
Tuple decoding uses the above types when storing values.
Using Java enum
types
SQL Server does not have ENUM
data type, but the client can map the retrieved string/numeric data type to enum.
You can encode Java enums like this:
client
.preparedQuery("INSERT INTO colors VALUES (@p1)")
.execute(Tuple.of(Color.red), res -> {
// ...
});
You can decode a Java enum like this:
client
.preparedQuery("SELECT color FROM colors")
.execute()
.onComplete(res -> {
if (res.succeeded()) {
RowSet<Row> rows = res.result();
for (Row row : rows) {
System.out.println(row.get(Color.class, "color"));
}
}
});
Handling NULL
If you modify a Tuple
with one of the addXXX
methods, null
values are handled transparently.
The client can infer the right SQL type when executing a prepared query:
Tuple tuple = Tuple.tuple()
.addInteger(17)
.addString("The Man Who Knew Too Much")
.addString(null);
client
.preparedQuery("INSERT INTO movies (id, title, plot) VALUES (@p1, @p2, @p3)")
.execute(tuple, res -> {
// ...
});
Otherwise, you should declare the type explicitely using one of the NullValue
constants or the NullValue.of
method:
Tuple tuple = Tuple.of(17, "The Man Who Knew Too Much", NullValue.String);
client
.preparedQuery("INSERT INTO movies (id, title, plot) VALUES (@p1, @p2, @p3)")
.execute(tuple, res -> {
// ...
});
Collector queries
You can use Java collectors with the query API:
Collector<Row, ?, Map<Long, String>> collector = Collectors.toMap(
row -> row.getLong("id"),
row -> row.getString("last_name"));
// Run the query with the collector
client.query("SELECT * FROM users")
.collecting(collector)
.execute(ar -> {
if (ar.succeeded()) {
SqlResult<Map<Long, String>> result = ar.result();
// Get the map created by the collector
Map<Long, String> map = result.value();
System.out.println("Got " + map);
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});
The collector processing must not keep a reference on the Row
as
there is a single row used for processing the entire set.
The Java Collectors
provides many interesting predefined collectors, for example you can
create easily create a string directly from the row set:
Collector<Row, ?, String> collector = Collectors.mapping(
row -> row.getString("last_name"),
Collectors.joining(",", "(", ")")
);
// Run the query with the collector
client.query("SELECT * FROM users")
.collecting(collector)
.execute(ar -> {
if (ar.succeeded()) {
SqlResult<String> result = ar.result();
// Get the string created by the collector
String list = result.value();
System.out.println("Got " + list);
} else {
System.out.println("Failure: " + ar.cause().getMessage());
}
});