/*
* @(#)JoinRowSet.java 1.7 04/05/29
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.sql.rowset;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
import java.io.*;
import java.math.*;
import java.util.*;
import javax.sql.rowset.*;
/**
* The <code>JoinRowSet</code> interface provides a mechanism for combining related
* data from different <code>RowSet</code> objects into one <code>JoinRowSet</code>
* object, which represents an SQL <code>JOIN</code>.
* In other words, a <code>JoinRowSet</code> object acts as a
* container for the data from <code>RowSet</code> objects that form an SQL
* <code>JOIN</code> relationship.
* <P>
* The <code>Joinable</code> interface provides the methods for setting,
* retrieving, and unsetting a match column, the basis for
* establishing an SQL <code>JOIN</code> relationship. The match column may
* alternatively be set by supplying it to the appropriate version of the
* <code>JointRowSet</code> method <code>addRowSet</code>.
* <P>
* <p>
* <h3>1.0 Overview</h3>
* Disconnected <code>RowSet</code> objects (<code>CachedRowSet</code> objects
* and implementations extending the <code>CachedRowSet</code> interface)
* do not have a standard way to establish an SQL <code>JOIN</code> between
* <code>RowSet</code> objects without the expensive operation of
* reconnecting to the data source. The <code>JoinRowSet</code>
* interface is specifically designed to address this need.
* <P>
* Any <code>RowSet</code> object
* can be added to a <code>JoinRowSet</code> object to become
* part of an SQL <code>JOIN</code> relationship. This means that both connected
* and disconnected <code>RowSet</code> objects can be part of a <code>JOIN</code>.
* <code>RowSet</code> objects operating in a connected environment
* (<code>JdbcRowSet</code> objects) are
* encouraged to use the database to which they are already
* connected to establish SQL <code>JOIN</code> relationships between
* tables directly. However, it is possible for a
* <code>JdbcRowSet</code> object to be added to a <code>JoinRowSet</code> object
* if necessary.
* <P>
* Any number of <code>RowSet</code> objects can be added to an
* instance of <code>JoinRowSet</code> provided that they
* can be related in an SQL <code>JOIN</code>.
* By definition, the SQL <code>JOIN</code> statement is used to
* combine the data contained in two or more relational database tables based
* upon a common attribute. The <code>Joinable</code> interface provides the methods
* for establishing a common attribute, which is done by setting a
* <i>match column</i>. The match column commonly coincides with
* the primary key, but there is
* no requirement that the match column be the same as the primary key.
* By establishing and then enforcing column matches,
* a <code>JoinRowSet</code> object establishes <code>JOIN</code> relationships
* between <code>RowSet</code> objects without the assistance of an available
* relational database.
* <P>
* The type of <code>JOIN</code> to be established is determined by setting
* one of the <code>JoinRowSet</code> constants using the method
* <code>setJoinType</code>. The following SQL <code>JOIN</code> types can be set:
* <UL>
* <LI><code>CROSS_JOIN</code>
* <LI><code>FULL_JOIN</code>
* <LI><code>INNER_JOIN</code> - the default if no <code>JOIN</code> type has been set
* <LI><code>LEFT_OUTER_JOIN</code>
* <LI><code>RIGHT_OUTER_JOIN</code>
* </UL>
* Note that if no type is set, the <code>JOIN</code> will automatically be an
* inner join. The comments for the fields in the
* <code>JoinRowSet</code> interface explain these <code>JOIN</code> types, which are
* standard SQL <code>JOIN</code> types.
* <P>
* <h3>2.0 Using a <code>JoinRowSet</code> Object for Creating a <code>JOIN</code></h3>
* When a <code>JoinRowSet</code> object is created, it is empty.
* The first <code>RowSet</code> object to be added becomes the basis for the
* <code>JOIN</code> relationship.
* Applications must determine which column in each of the
* <code>RowSet</code> objects to be added to the <code>JoinRowSet</code> object
* should be the match column. All of the
* <code>RowSet</code> objects must contain a match column, and the values in
* each match column must be ones that can be compared to values in the other match
* columns. The columns do not have to have the same name, though they often do,
* and they do not have to store the exact same data type as long as the data types
* can be compared.
* <P>
* A match column can be be set in two ways:
* <ul>
* <li>By calling the <code>Joinable</code> method <code>setMatchColumn</code><br>
* This is the only method that can set the match column before a <code>RowSet</code>
* object is added to a <code>JoinRowSet</code> object. The <code>RowSet</code> object
* must have implemented the <code>Joinable</code> interface in order to use the method
* <code>setMatchColumn</code>. Once the match column value
* has been set, this method can be used to reset the match column at any time.
* <li>By calling one of the versions of the <code>JoinRowSet</code> method
* <code>addRowSet</code> that takes a column name or number (or an array of
* column names or numbers)<BR>
* Four of the five <code>addRowSet</code> methods take a match column as a parameter.
* These four methods set or reset the match column at the time a <code>RowSet</code>
* object is being added to a <code>JoinRowSet</code> object.
* </ul>
* <h3>3.0 Sample Usage</h3>
* <p>
* The following code fragment adds two <code>CachedRowSet</code>
* objects to a <code>JoinRowSet</code> object. Note that in this example,
* no SQL <code>JOIN</code> type is set, so the default <code>JOIN</code> type,
* which is <i>INNER_JOIN</i>, is established.
* <p>
* In the following code fragment, the table <code>EMPLOYEES</code>, whose match
* column is set to the first column (<code>EMP_ID</code>), is added to the
* <code>JoinRowSet</code> object <i>jrs</i>. Then
* the table <code>ESSP_BONUS_PLAN</code>, whose match column is likewise
* the <code>EMP_ID</code> column, is added. When this second
* table is added to <i>jrs</i>, only the rows in
* <code>ESSP_BONUS_PLAN</code> whose <code>EMP_ID</code> value matches an
* <code>EMP_ID</code> value in the <code>EMPLOYEES</code> table are added.
* In this case, everyone in the bonus plan is an employee, so all of the rows
* in the table <code>ESSP_BONUS_PLAN</code> are added to the <code>JoinRowSet</code>
* object. In this example, both <code>CachedRowSet</code> objects being added
* have implemented the <code>Joinable</code> interface and can therefore call
* the <code>Joinable</code> method <code>setMatchColumn</code>.
* <PRE>
* JoinRowSet jrs = new JoinRowSetImpl();
*
* ResultSet rs1 = stmt.executeQuery("SELECT * FROM EMPLOYEES");
* CachedRowSet empl = new CachedRowSetImpl();
* empl.populate(rs1);
* empl.setMatchColumn(1);
* jrs.addRowSet(empl);
*
* ResultSet rs2 = stmt.executeQuery("SELECT * FROM ESSP_BONUS_PLAN");
* CachedRowSet bonus = new CachedRowSetImpl();
* bonus.populate(rs2);
* bonus.setMatchColumn(1); // EMP_ID is the first column
* jrs.addRowSet(bonus);
* </PRE>
* <P>
* At this point, <i>jrs</i> is an inside JOIN of the two <code>RowSet</code> objects
* based on their <code>EMP_ID</code> columns. The application can now browse the
* combined data as if it were browsing one single <code>RowSet</code> object.
* Because <i>jrs</i> is itself a <code>RowSet</code> object, an application can
* navigate or modify it using <code>RowSet</code> methods.
* <PRE>
* jrs.first();
* int employeeID = jrs.getInt(1);
* String employeeName = jrs.getString(2);
* </PRE>
* <P>
* Note that because the SQL <code>JOIN</code> must be enforced when an application
* adds a second or subsequent <code>RowSet</code> object, there
* may be an initial degradation in performance while the <code>JOIN</code> is
* being performed.
* <P>
* The following code fragment adds an additional <code>CachedRowSet</code> object.
* In this case, the match column (<code>EMP_ID</code>) is set when the
* <code>CachedRowSet</code> object is added to the <code>JoinRowSet</code> object.
* <PRE>
* ResultSet rs3 = stmt.executeQuery("SELECT * FROM 401K_CONTRIB");
* CachedRowSet fourO1k = new CachedRowSetImpl();
* four01k.populate(rs3);
* jrs.addRowSet(four01k, 1);
* </PRE>
* <P>
* The <code>JoinRowSet</code> object <i>jrs</i> now contains values from all three
* tables. The data in each row in <i>four01k</i> in which the value for the
* <code>EMP_ID</code> column matches a value for the <code>EMP_ID</code> column
* in <i>jrs</i> has been added to <i>jrs</i>.
* <P>
* <h3>4.0 <code>JoinRowSet</code> Methods</h3>
* The <code>JoinRowSet</code> interface supplies several methods for adding
* <code>RowSet</code> objects and for getting information about the
* <code>JoinRowSet</code> object.
* <UL>
* <LI>Methods for adding one or more <code>RowSet</code> objects<BR>
* These methods allow an application to add one <code>RowSet</code> object
* at a time or to add multiple <code>RowSet</code> objects at one time. In
* either case, the methods may specify the match column for each
* <code>RowSet</code> object being added.
* <LI>Methods for getting information<BR>
* One method retrieves the <code>RowSet</code> objects in the
* <code>JoinRowSet</code> object, and another method retrieves the
* <code>RowSet</code> names. A third method retrieves either the SQL
* <code>WHERE</code> clause used behind the scenes to form the
* <code>JOIN</code> or a text description of what the <code>WHERE</code>
* clause does.
* <LI>Methods related to the type of <code>JOIN</code><BR>
* One method sets the <code>JOIN</code> type, and five methods find out whether
* the <code>JoinRowSet</code> object supports a given type.
* <LI>A method to make a separate copy of the <code>JoinRowSet</code> object<BR>
* This method creates a copy that can be persisted to the data source.
* </UL>
* <P>
*/
public interface JoinRowSet extends WebRowSet {
/**
* Adds the given <code>RowSet</code> object to this <code>JoinRowSet</code>
* object. If the <code>RowSet</code> object
* is the first to be added to this <code>JoinRowSet</code>
* object, it forms the basis of the <code>JOIN</code> relationship to be
* established.
* <P>
* This method should be used only when the given <code>RowSet</code>
* object already has a match column that was set with the <code>Joinable</code>
* method <code>setMatchColumn</code>.
* <p>
* Note: A <code>Joinable</code> object is any <code>RowSet</code> object
* that has implemented the <code>Joinable</code> interface.
*
* @param rowset the <code>RowSet</code> object that is to be added to this
* <code>JoinRowSet</code> object; it must implement the
* <code>Joinable</code> interface and have a match column set
* @throws SQLException if (1) an empty rowset is added to the to this
* <code>JoinRowSet</code> object, (2) a match column has not been
* set for <i>rowset</i>, or (3) <i>rowset</i>
* violates the active <code>JOIN</code>
* @see Joinable#setMatchColumn
*/
public void addRowSet(Joinable rowset) throws SQLException;
/**
* Adds the given <code>RowSet</code> object to this <code>JoinRowSet</code>
* object and sets the designated column as the match column for
* the <code>RowSet</code> object. If the <code>RowSet</code> object
* is the first to be added to this <code>JoinRowSet</code>
* object, it forms the basis of the <code>JOIN</code> relationship to be
* established.
* <P>
* This method should be used when <i>RowSet</i> does not already have a match
* column set.
*
* @param rowset the <code>RowSet</code> object that is to be added to this
* <code>JoinRowSet</code> object; it may implement the
* <code>Joinable</code> interface
* @param columnIdx an <code>int</code> that identifies the column to become the
* match column
* @throws SQLException if (1) <i>rowset</i> is an empty rowset or
* (2) <i>rowset</i> violates the active <code>JOIN</code>
* @see Joinable#unsetMatchColumn
*/
public void addRowSet(RowSet rowset, int columnIdx) throws SQLException;
/**
* Adds <i>rowset</i> to this <code>JoinRowSet</code> object and
* sets the designated column as the match column. If <i>rowset</i>
* is the first to be added to this <code>JoinRowSet</code>
* object, it forms the basis for the <code>JOIN</code> relationship to be
* established.
* <P>
* This method should be used when the given <code>RowSet</code> object
* does not already have a match column.
*
* @param rowset the <code>RowSet</code> object that is to be added to this
* <code>JoinRowSet</code> object; it may implement the
* <code>Joinable</code> interface
* @param columnName the <code>String</code> object giving the name of the
* column to be set as the match column
* @throws SQLException if (1) <i>rowset</i> is an empty rowset or
* (2) the match column for <i>rowset</i> does not satisfy the
* conditions of the <code>JOIN</code>
*/
public void addRowSet(RowSet rowset,
String columnName) throws SQLException;
/**
* Adds one or more <code>RowSet</code> objects contained in the given
* array of <code>RowSet</code> objects to this <code>JoinRowSet</code>
* object and sets the match column for
* each of the <code>RowSet</code> objects to the match columns
* in the given array of column indexes. The first element in
* <i>columnIdx</i> is set as the match column for the first
* <code>RowSet</code> object in <i>rowset</i>, the second element of
* <i>columnIdx</i> is set as the match column for the second element
* in <i>rowset</i>, and so on.
* <P>
* The first <code>RowSet</code> object added to this <code>JoinRowSet</code>
* object forms the basis for the <code>JOIN</code> relationship.
* <P>
* This method should be used when the given <code>RowSet</code> object
* does not already have a match column.
*
* @param rowset an array of one or more <code>RowSet</code> objects
* to be added to the <code>JOIN</code>; it may implement the
* <code>Joinable</code> interface
* @param columnIdx an array of <code>int</code> values indicating the index(es)
* of the columns to be set as the match columns for the <code>RowSet</code>
* objects in <i>rowset</i>
* @throws SQLException if (1) an empty rowset is added to this
* <code>JoinRowSet</code> object, (2) a match column is not set
* for a <code>RowSet</code> object in <i>rowset</i>, or (3)
* a <code>RowSet</code> object being added violates the active
* <code>JOIN</code>
*/
public void addRowSet(RowSet[] rowset,
int[] columnIdx) throws SQLException;
/**
* Adds one or more <code>RowSet</code> objects contained in the given
* array of <code>RowSet</code> objects to this <code>JoinRowSet</code>
* object and sets the match column for
* each of the <code>RowSet</code> objects to the match columns
* in the given array of column names. The first element in
* <i>columnName</i> is set as the match column for the first
* <code>RowSet</code> object in <i>rowset</i>, the second element of
* <i>columnName</i> is set as the match column for the second element
* in <i>rowset</i>, and so on.
* <P>
* The first <code>RowSet</code> object added to this <code>JoinRowSet</code>
* object forms the basis for the <code>JOIN</code> relationship.
* <P>
* This method should be used when the given <code>RowSet</code> object(s)
* does not already have a match column.
*
* @param rowset an array of one or more <code>RowSet</code> objects
* to be added to the <code>JOIN</code>; it may implement the
* <code>Joinable</code> interface
* @param columnName an array of <code>String</code> values indicating the
* names of the columns to be set as the match columns for the
* <code>RowSet</code> objects in <i>rowset</i>
* @throws SQLException if (1) an empty rowset is added to this
* <code>JoinRowSet</code> object, (2) a match column is not set
* for a <code>RowSet</code> object in <i>rowset</i>, or (3)
* a <code>RowSet</code> object being added violates the active
* <code>JOIN</code>
*/
public void addRowSet(RowSet[] rowset,
String[] columnName) throws SQLException;
/**
* Returns a <code>Collection</code> object containing the
* <code>RowSet</code> objects that have been added to this
* <code>JoinRowSet</code> object.
* This should return the 'n' number of RowSet contained
* within the <code>JOIN</code> and maintain any updates that have occured while in
* this union.
*
* @return a <code>Collection</code> object consisting of the
* <code>RowSet</code> objects added to this <code>JoinRowSet</code>
* object
* @throws SQLException if an error occurs generating the
* <code>Collection</code> object to be returned
*/
public Collection<?> getRowSets() throws java.sql.SQLException;
/**
* Returns a <code>String</code> array containing the names of the
* <code>RowSet</code> objects added to this <code>JoinRowSet</code>
* object.
*
* @return a <code>String</code> array of the names of the
* <code>RowSet</code> objects in this <code>JoinRowSet</code>
* object
* @throws SQLException if an error occurs retrieving the names of
* the <code>RowSet</code> objects
* @see CachedRowSet#setTableName
*/
public String[] getRowSetNames() throws java.sql.SQLException;
/**
* Creates a new <code>CachedRowSet</code> object containing the
* data in this <code>JoinRowSet</code> object, which can be saved
* to a data source using the <code>SyncProvider</code> object for
* the <code>CachedRowSet</code> object.
* <P>
* If any updates or modifications have been applied to the JoinRowSet
* the CachedRowSet returned by the method will not be able to persist
* it's changes back to the originating rows and tables in the
* in the datasource. The CachedRowSet instance returned should not
* contain modification data and it should clear all properties of
* it's originating SQL statement. An application should reset the
* SQL statement using the <code>RowSet.setCommand</code> method.
* <p>
* In order to allow changes to be persisted back to the datasource
* to the originating tables, the <code>acceptChanges</code> method
* should be used and called on a JoinRowSet object instance. Implementations
* can leverage the internal data and update tracking in their
* implementations to interact with the SyncProvider to persist any
* changes.
*
* @return a CachedRowSet containing the contents of the JoinRowSet
* @throws SQLException if an error occurs assembling the CachedRowSet
* object
* @see javax.sql.RowSet
* @see javax.sql.rowset.CachedRowSet
* @see javax.sql.rowset.spi.SyncProvider
*/
public CachedRowSet toCachedRowSet() throws java.sql.SQLException;
/**
* Indicates if CROSS_JOIN is supported by a JoinRowSet
* implementation
*
* @return true if the CROSS_JOIN is supported; false otherwise
*/
public boolean supportsCrossJoin();
/**
* Indicates if INNER_JOIN is supported by a JoinRowSet
* implementation
*
* @return true is the INNER_JOIN is supported; false otherwise
*/
public boolean supportsInnerJoin();
/**
* Indicates if LEFT_OUTER_JOIN is supported by a JoinRowSet
* implementation
*
* @return true is the LEFT_OUTER_JOIN is supported; false otherwise
*/
public boolean supportsLeftOuterJoin();
/**
* Indicates if RIGHT_OUTER_JOIN is supported by a JoinRowSet
* implementation
*
* @return true is the RIGHT_OUTER_JOIN is supported; false otherwise
*/
public boolean supportsRightOuterJoin();
/**
* Indicates if FULL_JOIN is supported by a JoinRowSet
* implementation
*
* @return true is the FULL_JOIN is supported; false otherwise
*/
public boolean supportsFullJoin();
/**
* Allow the application to adjust the type of <code>JOIN</code> imposed
* on tables contained within the JoinRowSet object instance.
* Implementations should throw a SQLException if they do
* not support a given <code>JOIN</code> type.
*
* @param joinType the standard JoinRowSet.XXX static field definition
* of a SQL <code>JOIN</code> to re-configure a JoinRowSet instance on
* the fly.
* @throws SQLException if an unsupported <code>JOIN</code> type is set
* @see #getJoinType
*/
public void setJoinType(int joinType) throws SQLException;
/**
* Return a SQL-like description of the WHERE clause being used
* in a JoinRowSet object. An implementation can describe
* the WHERE clause of the SQL <code>JOIN</code> by supplying a SQL
* strings description of <code>JOIN</code> or provide a textual
* description to assist applications using a <code>JoinRowSet</code>
*
* @return whereClause a textual or SQL description of the logical
* WHERE clause used in the JoinRowSet instance
* @throws SQLException if an error occurs in generating a representation
* of the WHERE clause.
*/
public String getWhereClause() throws SQLException;
/**
* Returns a <code>int</code> describing the set SQL <code>JOIN</code> type
* governing this JoinRowSet instance. The returned type will be one of
* standard JoinRowSet types: <code>CROSS_JOIN</code>, <code>INNER_JOIN</code>,
* <code>LEFT_OUTER_JOIN</code>, <code>RIGHT_OUTER_JOIN</code> or
* <code>FULL_JOIN</code>.
*
* @return joinType one of the standard JoinRowSet static field
* definitions of a SQL <code>JOIN</code>. <code>JoinRowSet.INNER_JOIN</code>
* is returned as the default <code>JOIN</code> type is no type has been
* explicitly set.
* @throws SQLException if an error occurs determining the SQL <code>JOIN</code>
* type supported by the JoinRowSet instance.
* @see #setJoinType
*/
public int getJoinType() throws SQLException;
/**
* An ANSI-style <code>JOIN</code> providing a cross product of two tables
*/
public static int CROSS_JOIN = 0;
/**
* An ANSI-style <code>JOIN</code> providing a inner join between two tables. Any
* unmatched rows in either table of the join should be discarded.
*/
public static int INNER_JOIN = 1;
/**
* An ANSI-style <code>JOIN</code> providing a left outer join between two
* tables. In SQL, this is described where all records should be
* returned from the left side of the JOIN statement.
*/
public static int LEFT_OUTER_JOIN = 2;
/**
* An ANSI-style <code>JOIN</code> providing a right outer join between
* two tables. In SQL, this is described where all records from the
* table on the right side of the JOIN statement even if the table
* on the left has no matching record.
*/
public static int RIGHT_OUTER_JOIN = 3;
/**
* An ANSI-style <code>JOIN</code> providing a a full JOIN. Specifies that all
* rows from either table be returned regardless of matching
* records on the other table.
*/
public static int FULL_JOIN = 4;
}
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