Java Doc for jdbcCallableStatement.java in  » Database-DBMS » hsql » org » hsqldb » jdbc » Java Source Code / Java DocumentationJava Source Code and Java Documentation

 {?= call <procedure-name>[<arg1>,<arg2>, ...]}
 {call <procedure-name>[<arg1>,<arg2>, ...]}
 

HSQLDB-Specific Information:

Since 1.7.2, the JDBC CallableStatement interface implementation has been broken out of the jdbcPreparedStatement class into this one.

With 1.7.2, some of the previously unsupported features of this interface are now supported, such as the parameterName-based setter methods.

More importantly, jdbcCallableStatement objects are now backed by a true compiled parameteric representation. Hence, there are now significant performance gains to be had by using a CallableStatement object instead of a Statement object, if a short-running CALL statement is to be executed more than a small number of times. Moreover, the recent work lays the foundation for work in a subsequenct release to support CallableStatement OUT and IN OUT style parameters, as well as the generation and retrieval of multiple results in response to the execution of a CallableStatement object.

For a more in-depth discussion of performance issues regarding 1.7.2 prepared and callable statement objects, please see overview section of jdbcPreparedStatement jdbcPreparedStatment .

---

As with many DBMS, HSQLDB support for stored procedures is not provided in a completely standard fashion.

Beyond the XOpen/ODBC extended scalar functions, stored procedures are typically supported in ways that vary greatly from one DBMS implementation to the next. So, it is almost guaranteed that the code for a stored procedure written under a specific DBMS product will not work without at least some modification in the context of another vendor's product or even across a single vendor's product lines. Moving stored procedures from one DBMS product line to another almost invariably involves complex porting issues and often may not be possible at all. Be warned.

At present, HSQLDB stored procedures map directly onto the methods of compiled Java classes found on the classpath of the engine at runtime. This is done in a non-standard but fairly efficient way by issuing a class grant (and possibly method aliases) of the form:

 GRANT ALL ON CLASS "package.class" TO [<user-name> | PUBLIC]
 CREATE ALIAS <call-alias> FOR "package.class.method" -- optional
 

This has the effect of allowing the specified user(s) to access the set of uniquely named public static methods of the specified class, in either the role of SQL functions or stored procedures. For example:

 CONNECT <admin-user> PASSWORD <admin-user-password>;
 GRANT ALL ON CLASS "org.myorg.MyClass" TO PUBLIC;
 CREATE ALIAS sp_my_method FOR "org.myorg.MyClass.myMethod"
 CONNECT <any-user> PASSWORD <any-user-password>;
 SELECT "org.myorg.MyClass.myMethod"(column_1) FROM table_1;
 SELECT sp_my_method(column_1) FROM table_1;
 CALL 2 + "org.myorg.MyClass.myMethod"(-5);
 CALL 2 + sp_my_method(-5);
 

Please note the use of the term "uniquely named" above. Including 1.7.2, no support is provided to deterministically resolve overloaded method names, and there can be issues with inherited methods as well; currently, it is strongly recommended that developers creating stored procedure library classes for HSQLDB simply avoid designs such that SQL stored procedure calls attempt to resolve to:

1. inherited public static methods
2. overloaded public static methods

Also, please note that OUT and IN OUT parameters are not yet supported due to some unresolved low level support issues.

Including 1.7.2, the HSQLDB stored procedure call mechanism is essentially a thin wrap of the HSQLDB SQL function call mechanism, extended to include the more general HSQLDB SQL expression evaluation mechanism. In addition to stored procedure calls that resolve directly to Java method invocations, the extention provides the ability to evaluate simple SQL expressions, possibly containing Java method invocations, outside any INSERT, UPDATE, DELETE or SELECT statement context.

With HSQLDB, executing a CALL statement that produces an opaque (OTHER) or known scalar object reference has virtually the same effect as:

 CREATE TABLE DUAL (dummy VARCHAR);
 INSERT INTO DUAL VALUES(NULL);
 SELECT <simple-expression> FROM DUAL;
 

As a transitional measure, HSQLDB provides the ability to materialize a general result set in response to stored procedure execution. In this case, the stored procedure's Java method descriptor must specify a return type of java.lang.Object for external use (although at any point in the devlopment cycle, other, proprietary return types may accepted internally for engine development purposes). When HSQLDB detects that the runtime class of the resulting Object is elligible, an automatic internal unwrapping is performed to correctly expose the underlying result set to the client, whether local or remote.

Additionally, HSQLDB automatically detects if java.sql.Connection is the class of the first argument of any underlying Java method(s). If so, then the engine transparently supplies the internal Connection object corresponding to the Session executing the call, adjusting the positions of other arguments to suite the SQL context.

The features above are not intended to be permanent. Rather, the intention is to offer more general and powerful mechanisms in a future release; it is recommend to use them only as a temporary convenience.

For instance, one might be well advised to future-proof by writing HSQLDB-specific adapter methods that in turn call the real logic of an underlying generalized JDBC stored procedure library.

Here is a very simple example of an HSQLDB stored procedure generating a user-defined result set:

 package mypackage;
 class MyClass {
 public static Object mySp(Connection conn) throws SQLException {
 return conn.createStatement().executeQuery("select * from my_table");
 }
 }
 

Here is a refinement demonstrating no more than the bare essence of the idea behind a more portable style:

 package mypackage;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 class MyLibraryClass {
 public static ResultSet mySp() throws SQLException {
 return ctx.getConnection().createStatement().executeQuery("select * from my_table");
 }
 }
 //--
 package myadaptorpackage;
 import java.sql.Connection;
 import java.sql.SQLException;
 class MyAdaptorClass {
 public static Object mySp(Connection conn) throws SQLException {
 MyLibraryClass.getCtx().setConnection(conn);
 return MyLibraryClass.mySp();
 }
 }
 

In a future release, it is intended to provided some new features that will support writing fairly portable JDBC-based stored procedure code:

• Support for the "jdbc:default:connection" standard database connection url.

• A well-defined specification of the behaviour of the HSQLDB execution stack under stored procedure calls.

• A well-defined, pure JDBC specification for generating multiple results from HSQLDB stored procedures for client retrieval.

(boucherb@users)

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

Starting with 1.7.2, HSLQDB supports this.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.

HSQLDB-Specific Information:

HSQLDB 1.7.2 does not support this feature.

Calling this method always throws an SQLException.