com.buzzsurf.sql
Class Delete

java.lang.Object
  com.buzzsurf.sql.BuzzSQL
      com.buzzsurf.sql.Update
          com.buzzsurf.sql.Delete

public class Delete
extends Update

An Delete object deletes rows from a database table and queries the number of rows deleted. It is a combination of the underlying JDBC classes;

• java.sql.Connection
• java.sql.PreparedStatement

After execution, you may get the number of rows deleted by calling getDeleteCount() or getRowCount().

com.buzzsurf.sql.Delete extends com.buzzsurf.sql.Update, but add only minor functionality beyond that which is contained in the parent class. Therefore you may choose to use com.buzzsurf.sql.Update to perform deletes if it helps to streamline your object structure.

As an example, the following code fragment creates an Delete object using the automatic default connection to the database. The SQL statement is passed via constructor, and the arguments are passed using the setArgs(Object...) method. execute() is called to execute the database call, and then the delete count is queries by calling getDeleteCount(). The object is then closed to cleanup any resources and return the connection to the pool.

 Delete delete = new Delete();
 delete.setSQL("delete from example.table_example1 where col_int = ?");
 delete.setArgs(123);
 delete.execute();
 int deleteCount = update.getDeleteCount();
 delete.close();
 

Note: This code does not handle exceptions. You normally should wrap your calls in try/catch/finally blocks to handle any problems. It is advisable to put your close() call in a finally block to insure the connection is always released.

Author:

Paul Cowan (www.buzzsurf.com/sql)

See Also:

BuzzSQL, Update

Field Summary

Fields inherited from class com.buzzsurf.sql.Update

rowCount

Fields inherited from class com.buzzsurf.sql.BuzzSQL

args, con, DATABASE_FORMATTER, dataSourceName, sql, stmt, usingExplicitConnection

Constructor Summary

Delete()
A zero argument constructor is provided for simplified operation with JavBeans, SOAP, and reflection scenarios where having such a constructor is necessary or convenient.

Delete(java.lang.String sql)
A single argument constructor that accepts your SQL statement and uses the default DataSource.

Delete(java.lang.String sql, java.sql.Connection con)
A dual argument constructor that accepts your SQL statement and a java.sql.Connection object.

Delete(java.lang.String sql, java.lang.String dataSourceName)
A dual argument constructor that accepts your SQL statement and the explicit name of a DataSource to use.

Method Summary

Delete	execute() During execution a database connection is obtained (if needed), SQL and arguments are merged, and the PreparedStatement is executed against the database.
int	getDeleteCount() Get the number of rows deleted.

Methods inherited from class com.buzzsurf.sql.Update

getRowCount, getUpdateCount

Methods inherited from class com.buzzsurf.sql.BuzzSQL

addArgs, close, close, getArgs, getConnection, getDataSourceName, getReleaseInfo, getSQL, getStatement, merge, prepare, queryToString, setArgs, setConnection, setDataSourceName, setSQL, usingExplicitConnection

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Delete

public Delete()

A zero argument constructor is provided for simplified operation with JavBeans, SOAP, and reflection scenarios where having such a constructor is necessary or convenient. At a minimum, you must call setSQL(String) before execution when using this constructor.

Delete

public Delete(java.lang.String sql)

A single argument constructor that accepts your SQL statement and uses the default DataSource.

Parameters:

sql - The SQL statement

Delete

public Delete(java.lang.String sql,
              java.lang.String dataSourceName)

A dual argument constructor that accepts your SQL statement and the explicit name of a DataSource to use.

Parameters:

sql - The SQL statement

dataSourceName - The explicit name of the dataSource to obtain a connecton from in DataSourceManager.

Delete

public Delete(java.lang.String sql,
              java.sql.Connection con)

A dual argument constructor that accepts your SQL statement and a java.sql.Connection object. This constructor provides a great deal of flexibility by allowing the use of "explicit" connections that are supplied by the user rather than being obtained automatically by BuzzSQL. Using a explicit connection also allows BuzzSQL to support database transactions.

Parameters:

sql - The SQL statement

con - The explicit database Connection

Method Detail

getDeleteCount

public int getDeleteCount()

Get the number of rows deleted.

Returns:

Number of rows deleted

execute

public Delete execute()
               throws java.sql.SQLException

During execution a database connection is obtained (if needed), SQL and arguments are merged, and the PreparedStatement is executed against the database. execute() throws an exception if any of these steps fails for any reason.

Typical post-execution steps are slightly different depending on the object subtype. Select based objects will obtain a ResultSet and ResultSetMetaData, while Update based objects will query and save the updated row count to a local variable.

execute() returns a reference to the current object to support method chaining. See Method Chaining for more information. You can assume execution succeeded if no exception is thrown.

Overrides:

execute in class Update

Throws:

java.sql.SQLException - if any of the executing JDBC operations failed