[[jdbc-simple-jdbc]]
= Simplifying JDBC Operations with the `SimpleJdbc` Classes

The `SimpleJdbcInsert` and `SimpleJdbcCall` classes provide a simplified configuration
by taking advantage of database metadata that can be retrieved through the JDBC driver.
This means that you have less to configure up front, although you can override or turn off
the metadata processing if you prefer to provide all the details in your code.


[[jdbc-simple-jdbc-insert-1]]
== Inserting Data by Using `SimpleJdbcInsert`

We start by looking at the `SimpleJdbcInsert` class with the minimal amount of
configuration options. You should instantiate the `SimpleJdbcInsert` in the data access
layer's initialization method. For this example, the initializing method is the
`setDataSource` method. You do not need to subclass the `SimpleJdbcInsert` class. Instead,
you can create a new instance and set the table name by using the `withTableName` method.
Configuration methods for this class follow the `fluid` style that returns the instance
of the `SimpleJdbcInsert`, which lets you chain all configuration methods. The following
example uses only one configuration method (we show examples of multiple methods later):

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcInsert insertActor;

		public void setDataSource(DataSource dataSource) {
			this.insertActor = new SimpleJdbcInsert(dataSource).withTableName("t_actor");
		}

		public void add(Actor actor) {
			Map<String, Object> parameters = new HashMap<>(3);
			parameters.put("id", actor.getId());
			parameters.put("first_name", actor.getFirstName());
			parameters.put("last_name", actor.getLastName());
			insertActor.execute(parameters);
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val insertActor = SimpleJdbcInsert(dataSource).withTableName("t_actor")

		fun add(actor: Actor) {
			val parameters = mutableMapOf<String, Any>()
			parameters["id"] = actor.id
			parameters["first_name"] = actor.firstName
			parameters["last_name"] = actor.lastName
			insertActor.execute(parameters)
		}

		// ... additional methods
	}
----
======

The `execute` method used here takes a plain `java.util.Map` as its only parameter. The
important thing to note here is that the keys used for the `Map` must match the column
names of the table, as defined in the database. This is because we read the metadata
to construct the actual insert statement.


[[jdbc-simple-jdbc-insert-2]]
== Retrieving Auto-generated Keys by Using `SimpleJdbcInsert`

The next example uses the same insert as the preceding example, but, instead of passing in the `id`, it
retrieves the auto-generated key and sets it on the new `Actor` object. When it creates
the `SimpleJdbcInsert`, in addition to specifying the table name, it specifies the name
of the generated key column with the `usingGeneratedKeyColumns` method. The following
listing shows how it works:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcInsert insertActor;

		public void setDataSource(DataSource dataSource) {
			this.insertActor = new SimpleJdbcInsert(dataSource)
					.withTableName("t_actor")
					.usingGeneratedKeyColumns("id");
		}

		public void add(Actor actor) {
			Map<String, Object> parameters = new HashMap<>(2);
			parameters.put("first_name", actor.getFirstName());
			parameters.put("last_name", actor.getLastName());
			Number newId = insertActor.executeAndReturnKey(parameters);
			actor.setId(newId.longValue());
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val insertActor = SimpleJdbcInsert(dataSource)
				.withTableName("t_actor").usingGeneratedKeyColumns("id")

		fun add(actor: Actor): Actor {
			val parameters = mapOf(
					"first_name" to actor.firstName,
					"last_name" to actor.lastName)
			val newId = insertActor.executeAndReturnKey(parameters);
			return actor.copy(id = newId.toLong())
		}

		// ... additional methods
	}
----
======

The main difference when you run the insert by using this second approach is that you do not
add the `id` to the `Map`, and you call the `executeAndReturnKey` method. This returns a
`java.lang.Number` object with which you can create an instance of the numerical type that
is used in your domain class. You cannot rely on all databases to return a specific Java
class here. `java.lang.Number` is the base class that you can rely on. If you have
multiple auto-generated columns or the generated values are non-numeric, you can
use a `KeyHolder` that is returned from the `executeAndReturnKeyHolder` method.


[[jdbc-simple-jdbc-insert-3]]
== Specifying Columns for a `SimpleJdbcInsert`

You can limit the columns for an insert by specifying a list of column names with the
`usingColumns` method, as the following example shows:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcInsert insertActor;

		public void setDataSource(DataSource dataSource) {
			this.insertActor = new SimpleJdbcInsert(dataSource)
					.withTableName("t_actor")
					.usingColumns("first_name", "last_name")
					.usingGeneratedKeyColumns("id");
		}

		public void add(Actor actor) {
			Map<String, Object> parameters = new HashMap<>(2);
			parameters.put("first_name", actor.getFirstName());
			parameters.put("last_name", actor.getLastName());
			Number newId = insertActor.executeAndReturnKey(parameters);
			actor.setId(newId.longValue());
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val insertActor = SimpleJdbcInsert(dataSource)
				.withTableName("t_actor")
				.usingColumns("first_name", "last_name")
				.usingGeneratedKeyColumns("id")

		fun add(actor: Actor): Actor {
			val parameters = mapOf(
					"first_name" to actor.firstName,
					"last_name" to actor.lastName)
			val newId = insertActor.executeAndReturnKey(parameters);
			return actor.copy(id = newId.toLong())
		}

		// ... additional methods
	}
----
======

The execution of the insert is the same as if you had relied on the metadata to determine
which columns to use.


[[jdbc-simple-jdbc-parameters]]
== Using `SqlParameterSource` to Provide Parameter Values

Using a `Map` to provide parameter values works fine, but it is not the most convenient
class to use. Spring provides a couple of implementations of the `SqlParameterSource`
interface that you can use instead. The first one is `BeanPropertySqlParameterSource`,
which is a very convenient class if you have a JavaBean-compliant class that contains
your values. It uses the corresponding getter method to extract the parameter
values. The following example shows how to use `BeanPropertySqlParameterSource`:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcInsert insertActor;

		public void setDataSource(DataSource dataSource) {
			this.insertActor = new SimpleJdbcInsert(dataSource)
					.withTableName("t_actor")
					.usingGeneratedKeyColumns("id");
		}

		public void add(Actor actor) {
			SqlParameterSource parameters = new BeanPropertySqlParameterSource(actor);
			Number newId = insertActor.executeAndReturnKey(parameters);
			actor.setId(newId.longValue());
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val insertActor = SimpleJdbcInsert(dataSource)
				.withTableName("t_actor")
				.usingGeneratedKeyColumns("id")

		fun add(actor: Actor): Actor {
			val parameters = BeanPropertySqlParameterSource(actor)
			val newId = insertActor.executeAndReturnKey(parameters)
			return actor.copy(id = newId.toLong())
		}

		// ... additional methods
	}
----
======

Another option is the `MapSqlParameterSource` that resembles a `Map` but provides a more
convenient `addValue` method that can be chained. The following example shows how to use it:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcInsert insertActor;

		public void setDataSource(DataSource dataSource) {
			this.insertActor = new SimpleJdbcInsert(dataSource)
					.withTableName("t_actor")
					.usingGeneratedKeyColumns("id");
		}

		public void add(Actor actor) {
			SqlParameterSource parameters = new MapSqlParameterSource()
					.addValue("first_name", actor.getFirstName())
					.addValue("last_name", actor.getLastName());
			Number newId = insertActor.executeAndReturnKey(parameters);
			actor.setId(newId.longValue());
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val insertActor = SimpleJdbcInsert(dataSource)
				.withTableName("t_actor")
				.usingGeneratedKeyColumns("id")

		fun add(actor: Actor): Actor {
			val parameters = MapSqlParameterSource()
						.addValue("first_name", actor.firstName)
						.addValue("last_name", actor.lastName)
			val newId = insertActor.executeAndReturnKey(parameters)
			return actor.copy(id = newId.toLong())
		}

		// ... additional methods
	}
----
======

As you can see, the configuration is the same. Only the executing code has to change to
use these alternative input classes.


[[jdbc-simple-jdbc-call-1]]
== Calling a Stored Procedure with `SimpleJdbcCall`

The `SimpleJdbcCall` class uses metadata in the database to look up names of `in`
and `out` parameters so that you do not have to explicitly declare them. You can
declare parameters if you prefer to do that or if you have parameters that do not
have an automatic mapping to a Java class. The first example shows a simple procedure
that returns only scalar values in `VARCHAR` and `DATE` format from a MySQL database.
The example procedure reads a specified actor entry and returns `first_name`,
`last_name`, and `birth_date` columns in the form of `out` parameters. The following
listing shows the first example:

[source,sql,indent=0,subs="verbatim,quotes"]
----
	CREATE PROCEDURE read_actor (
		IN in_id INTEGER,
		OUT out_first_name VARCHAR(100),
		OUT out_last_name VARCHAR(100),
		OUT out_birth_date DATE)
	BEGIN
		SELECT first_name, last_name, birth_date
		INTO out_first_name, out_last_name, out_birth_date
		FROM t_actor where id = in_id;
	END;
----

The `in_id` parameter contains the `id` of the actor that you are looking up. The `out`
parameters return the data read from the table.

You can declare `SimpleJdbcCall` in a manner similar to declaring `SimpleJdbcInsert`. You
should instantiate and configure the class in the initialization method of your data-access
layer. Compared to the `StoredProcedure` class, you need not create a subclass
and you need not to declare parameters that can be looked up in the database metadata.
The following example of a `SimpleJdbcCall` configuration uses the preceding stored
procedure (the only configuration option, in addition to the `DataSource`, is the name
of the stored procedure):

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcCall procReadActor;

		public void setDataSource(DataSource dataSource) {
			this.procReadActor = new SimpleJdbcCall(dataSource)
					.withProcedureName("read_actor");
		}

		public Actor readActor(Long id) {
			SqlParameterSource in = new MapSqlParameterSource()
					.addValue("in_id", id);
			Map out = procReadActor.execute(in);
			Actor actor = new Actor();
			actor.setId(id);
			actor.setFirstName((String) out.get("out_first_name"));
			actor.setLastName((String) out.get("out_last_name"));
			actor.setBirthDate((Date) out.get("out_birth_date"));
			return actor;
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val procReadActor = SimpleJdbcCall(dataSource)
				.withProcedureName("read_actor")


		fun readActor(id: Long): Actor {
			val source = MapSqlParameterSource().addValue("in_id", id)
			val output = procReadActor.execute(source)
			return Actor(
					id,
					output["out_first_name"] as String,
					output["out_last_name"] as String,
					output["out_birth_date"] as Date)
		}

			// ... additional methods
	}
----
======

The code you write for the execution of the call involves creating an `SqlParameterSource`
containing the IN parameter. You must match the name provided for the input value
with that of the parameter name declared in the stored procedure. The case does not have
to match because you use metadata to determine how database objects should be referred to
in a stored procedure. What is specified in the source for the stored procedure is not
necessarily the way it is stored in the database. Some databases transform names to all
upper case, while others use lower case or use the case as specified.

The `execute` method takes the IN parameters and returns a `Map` that contains any `out`
parameters keyed by the name, as specified in the stored procedure. In this case, they are
`out_first_name`, `out_last_name`, and `out_birth_date`.

The last part of the `execute` method creates an `Actor` instance to use to return the
data retrieved. Again, it is important to use the names of the `out` parameters as they
are declared in the stored procedure. Also, the case in the names of the `out`
parameters stored in the results map matches that of the `out` parameter names in the
database, which could vary between databases. To make your code more portable, you should
do a case-insensitive lookup or instruct Spring to use a `LinkedCaseInsensitiveMap`.
To do the latter, you can create your own `JdbcTemplate` and set the `setResultsMapCaseInsensitive`
property to `true`. Then you can pass this customized `JdbcTemplate` instance into
the constructor of your `SimpleJdbcCall`. The following example shows this configuration:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcCall procReadActor;

		public void setDataSource(DataSource dataSource) {
			JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
			jdbcTemplate.setResultsMapCaseInsensitive(true);
			this.procReadActor = new SimpleJdbcCall(jdbcTemplate)
					.withProcedureName("read_actor");
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private var procReadActor = SimpleJdbcCall(JdbcTemplate(dataSource).apply {
			isResultsMapCaseInsensitive = true
		}).withProcedureName("read_actor")

		// ... additional methods
	}
----
======

By taking this action, you avoid conflicts in the case used for the names of your
returned `out` parameters.


[[jdbc-simple-jdbc-call-2]]
== Explicitly Declaring Parameters to Use for a `SimpleJdbcCall`

Earlier in this chapter, we described how parameters are deduced from metadata, but you can declare them
explicitly if you wish. You can do so by creating and configuring `SimpleJdbcCall` with
the `declareParameters` method, which takes a variable number of `SqlParameter` objects
as input. See the xref:data-access/jdbc/simple.adoc#jdbc-params[next section] for details on how to define an `SqlParameter`.

NOTE: Explicit declarations are necessary if the database you use is not a Spring-supported
database. Currently, Spring supports metadata lookup of stored procedure calls for the
following databases: Apache Derby, DB2, MySQL, Microsoft SQL Server, Oracle, and Sybase.
We also support metadata lookup of stored functions for MySQL, Microsoft SQL Server,
and Oracle.

You can opt to explicitly declare one, some, or all of the parameters. The parameter
metadata is still used where you do not explicitly declare parameters. To bypass all
processing of metadata lookups for potential parameters and use only the declared
parameters, you can call the method `withoutProcedureColumnMetaDataAccess` as part of the
declaration. Suppose that you have two or more different call signatures declared for a
database function. In this case, you call `useInParameterNames` to specify the list
of IN parameter names to include for a given signature.

The following example shows a fully declared procedure call and uses the information from
the preceding example:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcCall procReadActor;

		public void setDataSource(DataSource dataSource) {
			JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
			jdbcTemplate.setResultsMapCaseInsensitive(true);
			this.procReadActor = new SimpleJdbcCall(jdbcTemplate)
					.withProcedureName("read_actor")
					.withoutProcedureColumnMetaDataAccess()
					.useInParameterNames("in_id")
					.declareParameters(
							new SqlParameter("in_id", Types.NUMERIC),
							new SqlOutParameter("out_first_name", Types.VARCHAR),
							new SqlOutParameter("out_last_name", Types.VARCHAR),
							new SqlOutParameter("out_birth_date", Types.DATE)
					);
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

			private val procReadActor = SimpleJdbcCall(JdbcTemplate(dataSource).apply {
				isResultsMapCaseInsensitive = true
			}).withProcedureName("read_actor")
					.withoutProcedureColumnMetaDataAccess()
					.useInParameterNames("in_id")
					.declareParameters(
							SqlParameter("in_id", Types.NUMERIC),
							SqlOutParameter("out_first_name", Types.VARCHAR),
							SqlOutParameter("out_last_name", Types.VARCHAR),
							SqlOutParameter("out_birth_date", Types.DATE)
		)

			// ... additional methods
	}
----
======

The execution and end results of the two examples are the same. The second example specifies all
details explicitly rather than relying on metadata.


[[jdbc-params]]
== How to Define `SqlParameters`

To define a parameter for the `SimpleJdbc` classes and also for the RDBMS operations
classes (covered in xref:data-access/jdbc/object.adoc[Modeling JDBC Operations as Java Objects]) you can use `SqlParameter` or one of its subclasses.
To do so, you typically specify the parameter name and SQL type in the constructor. The SQL type
is specified by using the `java.sql.Types` constants. Earlier in this chapter, we saw declarations
similar to the following:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	new SqlParameter("in_id", Types.NUMERIC),
	new SqlOutParameter("out_first_name", Types.VARCHAR),
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	SqlParameter("in_id", Types.NUMERIC),
	SqlOutParameter("out_first_name", Types.VARCHAR),
----
======

The first line with the `SqlParameter` declares an IN parameter. You can use IN parameters
for both stored procedure calls and for queries by using the `SqlQuery` and its
subclasses (covered in xref:data-access/jdbc/object.adoc#jdbc-SqlQuery[Understanding `SqlQuery`]).

The second line (with the `SqlOutParameter`) declares an `out` parameter to be used in a
stored procedure call. There is also an `SqlInOutParameter` for `InOut` parameters
(parameters that provide an IN value to the procedure and that also return a value).

NOTE: Only parameters declared as `SqlParameter` and `SqlInOutParameter` are used to
provide input values. This is different from the `StoredProcedure` class, which (for
backwards compatibility reasons) lets input values be provided for parameters
declared as `SqlOutParameter`.

For IN parameters, in addition to the name and the SQL type, you can specify a scale for
numeric data or a type name for custom database types. For `out` parameters, you can
provide a `RowMapper` to handle mapping of rows returned from a `REF` cursor. Another
option is to specify an `SqlReturnType` that provides an opportunity to define
customized handling of the return values.


[[jdbc-simple-jdbc-call-3]]
== Calling a Stored Function by Using `SimpleJdbcCall`

You can call a stored function in almost the same way as you call a stored procedure, except
that you provide a function name rather than a procedure name. You use the
`withFunctionName` method as part of the configuration to indicate that you want to make
a call to a function, and the corresponding string for a function call is generated. A
specialized call (`executeFunction`) is used to run the function, and it
returns the function return value as an object of a specified type, which means you do
not have to retrieve the return value from the results map. A similar convenience method
(named `executeObject`) is also available for stored procedures that have only one `out`
parameter. The following example (for MySQL) is based on a stored function named `get_actor_name`
that returns an actor's full name:

[source,sql,indent=0,subs="verbatim,quotes"]
----
	CREATE FUNCTION get_actor_name (in_id INTEGER)
	RETURNS VARCHAR(200) READS SQL DATA
	BEGIN
		DECLARE out_name VARCHAR(200);
		SELECT concat(first_name, ' ', last_name)
			INTO out_name
			FROM t_actor where id = in_id;
		RETURN out_name;
	END;
----

To call this function, we again create a `SimpleJdbcCall` in the initialization method,
as the following example shows:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcCall funcGetActorName;

		public void setDataSource(DataSource dataSource) {
			JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
			jdbcTemplate.setResultsMapCaseInsensitive(true);
			this.funcGetActorName = new SimpleJdbcCall(jdbcTemplate)
					.withFunctionName("get_actor_name");
		}

		public String getActorName(Long id) {
			SqlParameterSource in = new MapSqlParameterSource()
					.addValue("in_id", id);
			String name = funcGetActorName.executeFunction(String.class, in);
			return name;
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

		private val jdbcTemplate = JdbcTemplate(dataSource).apply {
			isResultsMapCaseInsensitive = true
		}
		private val funcGetActorName = SimpleJdbcCall(jdbcTemplate)
				.withFunctionName("get_actor_name")

		fun getActorName(id: Long): String {
			val source = MapSqlParameterSource().addValue("in_id", id)
			return funcGetActorName.executeFunction(String::class.java, source)
		}

		// ... additional methods
	}
----
======

The `executeFunction` method used returns a `String` that contains the return value from the
function call.


[[jdbc-simple-jdbc-call-4]]
== Returning a `ResultSet` or REF Cursor from a `SimpleJdbcCall`

Calling a stored procedure or function that returns a result set is a bit tricky. Some
databases return result sets during the JDBC results processing, while others require an
explicitly registered `out` parameter of a specific type. Both approaches need
additional processing to loop over the result set and process the returned rows. With
the `SimpleJdbcCall`, you can use the `returningResultSet` method and declare a `RowMapper`
implementation to be used for a specific parameter. If the result set is
returned during the results processing, there are no names defined, so the returned
results must match the order in which you declare the `RowMapper`
implementations. The name specified is still used to store the processed list of results
in the results map that is returned from the `execute` statement.

The next example (for MySQL) uses a stored procedure that takes no IN parameters and returns
all rows from the `t_actor` table:

[source,sql,indent=0,subs="verbatim,quotes"]
----
	CREATE PROCEDURE read_all_actors()
	BEGIN
	 SELECT a.id, a.first_name, a.last_name, a.birth_date FROM t_actor a;
	END;
----

To call this procedure, you can declare the `RowMapper`. Because the class to which you want
to map follows the JavaBean rules, you can use a `BeanPropertyRowMapper` that is created by
passing in the required class to map to in the `newInstance` method.
The following example shows how to do so:

[tabs]
======
Java::
+
[source,java,indent=0,subs="verbatim,quotes"]
----
	public class JdbcActorDao implements ActorDao {

		private SimpleJdbcCall procReadAllActors;

		public void setDataSource(DataSource dataSource) {
			JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
			jdbcTemplate.setResultsMapCaseInsensitive(true);
			this.procReadAllActors = new SimpleJdbcCall(jdbcTemplate)
					.withProcedureName("read_all_actors")
					.returningResultSet("actors",
					BeanPropertyRowMapper.newInstance(Actor.class));
		}

		public List getActorsList() {
			Map m = procReadAllActors.execute(new HashMap<String, Object>(0));
			return (List) m.get("actors");
		}

		// ... additional methods
	}
----

Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
	class JdbcActorDao(dataSource: DataSource) : ActorDao {

			private val procReadAllActors = SimpleJdbcCall(JdbcTemplate(dataSource).apply {
				isResultsMapCaseInsensitive = true
			}).withProcedureName("read_all_actors")
					.returningResultSet("actors",
							BeanPropertyRowMapper.newInstance(Actor::class.java))

		fun getActorsList(): List<Actor> {
			val m = procReadAllActors.execute(mapOf<String, Any>())
			return m["actors"] as List<Actor>
		}

		// ... additional methods
	}
----
======

The `execute` call passes in an empty `Map`, because this call does not take any parameters.
The list of actors is then retrieved from the results map and returned to the caller.



