1 /*
2 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
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24 */
25
26 package javax.sql.rowset;
27
28 import java.sql.*;
29 import javax.sql.*;
30 import javax.naming.*;
31 import java.io.*;
32 import java.math.*;
33 import java.util.*;
34
35 import javax.sql.rowset.*;
36
37 /**
38 * The <code>JoinRowSet</code> interface provides a mechanism for combining related
39 * data from different <code>RowSet</code> objects into one <code>JoinRowSet</code>
40 * object, which represents an SQL <code>JOIN</code>.
41 * In other words, a <code>JoinRowSet</code> object acts as a
42 * container for the data from <code>RowSet</code> objects that form an SQL
43 * <code>JOIN</code> relationship.
44 * <P>
45 * The <code>Joinable</code> interface provides the methods for setting,
46 * retrieving, and unsetting a match column, the basis for
47 * establishing an SQL <code>JOIN</code> relationship. The match column may
48 * alternatively be set by supplying it to the appropriate version of the
49 * <code>JointRowSet</code> method <code>addRowSet</code>.
50 *
51 * <h3>1.0 Overview</h3>
52 * Disconnected <code>RowSet</code> objects (<code>CachedRowSet</code> objects
53 * and implementations extending the <code>CachedRowSet</code> interface)
54 * do not have a standard way to establish an SQL <code>JOIN</code> between
55 * <code>RowSet</code> objects without the expensive operation of
56 * reconnecting to the data source. The <code>JoinRowSet</code>
57 * interface is specifically designed to address this need.
58 * <P>
59 * Any <code>RowSet</code> object
60 * can be added to a <code>JoinRowSet</code> object to become
61 * part of an SQL <code>JOIN</code> relationship. This means that both connected
62 * and disconnected <code>RowSet</code> objects can be part of a <code>JOIN</code>.
63 * <code>RowSet</code> objects operating in a connected environment
64 * (<code>JdbcRowSet</code> objects) are
65 * encouraged to use the database to which they are already
66 * connected to establish SQL <code>JOIN</code> relationships between
67 * tables directly. However, it is possible for a
68 * <code>JdbcRowSet</code> object to be added to a <code>JoinRowSet</code> object
69 * if necessary.
70 * <P>
71 * Any number of <code>RowSet</code> objects can be added to an
72 * instance of <code>JoinRowSet</code> provided that they
73 * can be related in an SQL <code>JOIN</code>.
74 * By definition, the SQL <code>JOIN</code> statement is used to
75 * combine the data contained in two or more relational database tables based
76 * upon a common attribute. The <code>Joinable</code> interface provides the methods
77 * for establishing a common attribute, which is done by setting a
78 * <i>match column</i>. The match column commonly coincides with
79 * the primary key, but there is
80 * no requirement that the match column be the same as the primary key.
81 * By establishing and then enforcing column matches,
82 * a <code>JoinRowSet</code> object establishes <code>JOIN</code> relationships
83 * between <code>RowSet</code> objects without the assistance of an available
84 * relational database.
85 * <P>
86 * The type of <code>JOIN</code> to be established is determined by setting
87 * one of the <code>JoinRowSet</code> constants using the method
88 * <code>setJoinType</code>. The following SQL <code>JOIN</code> types can be set:
89 * <UL>
90 * <LI><code>CROSS_JOIN</code>
91 * <LI><code>FULL_JOIN</code>
92 * <LI><code>INNER_JOIN</code> - the default if no <code>JOIN</code> type has been set
93 * <LI><code>LEFT_OUTER_JOIN</code>
94 * <LI><code>RIGHT_OUTER_JOIN</code>
95 * </UL>
96 * Note that if no type is set, the <code>JOIN</code> will automatically be an
97 * inner join. The comments for the fields in the
98 * <code>JoinRowSet</code> interface explain these <code>JOIN</code> types, which are
99 * standard SQL <code>JOIN</code> types.
100 *
101 * <h3>2.0 Using a <code>JoinRowSet</code> Object for Creating a <code>JOIN</code></h3>
102 * When a <code>JoinRowSet</code> object is created, it is empty.
103 * The first <code>RowSet</code> object to be added becomes the basis for the
104 * <code>JOIN</code> relationship.
105 * Applications must determine which column in each of the
106 * <code>RowSet</code> objects to be added to the <code>JoinRowSet</code> object
107 * should be the match column. All of the
108 * <code>RowSet</code> objects must contain a match column, and the values in
109 * each match column must be ones that can be compared to values in the other match
110 * columns. The columns do not have to have the same name, though they often do,
111 * and they do not have to store the exact same data type as long as the data types
112 * can be compared.
113 * <P>
114 * A match column can be be set in two ways:
115 * <ul>
116 * <li>By calling the <code>Joinable</code> method <code>setMatchColumn</code><br>
117 * This is the only method that can set the match column before a <code>RowSet</code>
118 * object is added to a <code>JoinRowSet</code> object. The <code>RowSet</code> object
119 * must have implemented the <code>Joinable</code> interface in order to use the method
120 * <code>setMatchColumn</code>. Once the match column value
121 * has been set, this method can be used to reset the match column at any time.
122 * <li>By calling one of the versions of the <code>JoinRowSet</code> method
123 * <code>addRowSet</code> that takes a column name or number (or an array of
124 * column names or numbers)<BR>
125 * Four of the five <code>addRowSet</code> methods take a match column as a parameter.
126 * These four methods set or reset the match column at the time a <code>RowSet</code>
127 * object is being added to a <code>JoinRowSet</code> object.
128 * </ul>
129 * <h3>3.0 Sample Usage</h3>
130 * <p>
131 * The following code fragment adds two <code>CachedRowSet</code>
132 * objects to a <code>JoinRowSet</code> object. Note that in this example,
133 * no SQL <code>JOIN</code> type is set, so the default <code>JOIN</code> type,
134 * which is <i>INNER_JOIN</i>, is established.
135 * <p>
136 * In the following code fragment, the table <code>EMPLOYEES</code>, whose match
137 * column is set to the first column (<code>EMP_ID</code>), is added to the
138 * <code>JoinRowSet</code> object <i>jrs</i>. Then
139 * the table <code>ESSP_BONUS_PLAN</code>, whose match column is likewise
140 * the <code>EMP_ID</code> column, is added. When this second
141 * table is added to <i>jrs</i>, only the rows in
142 * <code>ESSP_BONUS_PLAN</code> whose <code>EMP_ID</code> value matches an
143 * <code>EMP_ID</code> value in the <code>EMPLOYEES</code> table are added.
144 * In this case, everyone in the bonus plan is an employee, so all of the rows
145 * in the table <code>ESSP_BONUS_PLAN</code> are added to the <code>JoinRowSet</code>
146 * object. In this example, both <code>CachedRowSet</code> objects being added
147 * have implemented the <code>Joinable</code> interface and can therefore call
148 * the <code>Joinable</code> method <code>setMatchColumn</code>.
149 * <PRE>
150 * JoinRowSet jrs = new JoinRowSetImpl();
151 *
152 * ResultSet rs1 = stmt.executeQuery("SELECT * FROM EMPLOYEES");
153 * CachedRowSet empl = new CachedRowSetImpl();
154 * empl.populate(rs1);
155 * empl.setMatchColumn(1);
156 * jrs.addRowSet(empl);
157 *
158 * ResultSet rs2 = stmt.executeQuery("SELECT * FROM ESSP_BONUS_PLAN");
159 * CachedRowSet bonus = new CachedRowSetImpl();
160 * bonus.populate(rs2);
161 * bonus.setMatchColumn(1); // EMP_ID is the first column
162 * jrs.addRowSet(bonus);
163 * </PRE>
164 * <P>
165 * At this point, <i>jrs</i> is an inside JOIN of the two <code>RowSet</code> objects
166 * based on their <code>EMP_ID</code> columns. The application can now browse the
167 * combined data as if it were browsing one single <code>RowSet</code> object.
168 * Because <i>jrs</i> is itself a <code>RowSet</code> object, an application can
169 * navigate or modify it using <code>RowSet</code> methods.
170 * <PRE>
171 * jrs.first();
172 * int employeeID = jrs.getInt(1);
173 * String employeeName = jrs.getString(2);
174 * </PRE>
175 * <P>
176 * Note that because the SQL <code>JOIN</code> must be enforced when an application
177 * adds a second or subsequent <code>RowSet</code> object, there
178 * may be an initial degradation in performance while the <code>JOIN</code> is
179 * being performed.
180 * <P>
181 * The following code fragment adds an additional <code>CachedRowSet</code> object.
182 * In this case, the match column (<code>EMP_ID</code>) is set when the
183 * <code>CachedRowSet</code> object is added to the <code>JoinRowSet</code> object.
184 * <PRE>
185 * ResultSet rs3 = stmt.executeQuery("SELECT * FROM 401K_CONTRIB");
186 * CachedRowSet fourO1k = new CachedRowSetImpl();
187 * four01k.populate(rs3);
188 * jrs.addRowSet(four01k, 1);
189 * </PRE>
190 * <P>
191 * The <code>JoinRowSet</code> object <i>jrs</i> now contains values from all three
192 * tables. The data in each row in <i>four01k</i> in which the value for the
193 * <code>EMP_ID</code> column matches a value for the <code>EMP_ID</code> column
194 * in <i>jrs</i> has been added to <i>jrs</i>.
195 *
196 * <h3>4.0 <code>JoinRowSet</code> Methods</h3>
197 * The <code>JoinRowSet</code> interface supplies several methods for adding
198 * <code>RowSet</code> objects and for getting information about the
199 * <code>JoinRowSet</code> object.
200 * <UL>
201 * <LI>Methods for adding one or more <code>RowSet</code> objects<BR>
202 * These methods allow an application to add one <code>RowSet</code> object
203 * at a time or to add multiple <code>RowSet</code> objects at one time. In
204 * either case, the methods may specify the match column for each
205 * <code>RowSet</code> object being added.
206 * <LI>Methods for getting information<BR>
207 * One method retrieves the <code>RowSet</code> objects in the
208 * <code>JoinRowSet</code> object, and another method retrieves the
209 * <code>RowSet</code> names. A third method retrieves either the SQL
210 * <code>WHERE</code> clause used behind the scenes to form the
211 * <code>JOIN</code> or a text description of what the <code>WHERE</code>
212 * clause does.
213 * <LI>Methods related to the type of <code>JOIN</code><BR>
214 * One method sets the <code>JOIN</code> type, and five methods find out whether
215 * the <code>JoinRowSet</code> object supports a given type.
216 * <LI>A method to make a separate copy of the <code>JoinRowSet</code> object<BR>
217 * This method creates a copy that can be persisted to the data source.
218 * </UL>
219 *
220 * @since 1.5
221 */
222
223 public interface JoinRowSet extends WebRowSet {
224
225 /**
226 * Adds the given <code>RowSet</code> object to this <code>JoinRowSet</code>
227 * object. If the <code>RowSet</code> object
228 * is the first to be added to this <code>JoinRowSet</code>
229 * object, it forms the basis of the <code>JOIN</code> relationship to be
230 * established.
231 * <P>
232 * This method should be used only when the given <code>RowSet</code>
233 * object already has a match column that was set with the <code>Joinable</code>
234 * method <code>setMatchColumn</code>.
235 * <p>
236 * Note: A <code>Joinable</code> object is any <code>RowSet</code> object
237 * that has implemented the <code>Joinable</code> interface.
238 *
239 * @param rowset the <code>RowSet</code> object that is to be added to this
240 * <code>JoinRowSet</code> object; it must implement the
241 * <code>Joinable</code> interface and have a match column set
242 * @throws SQLException if (1) an empty rowset is added to the to this
243 * <code>JoinRowSet</code> object, (2) a match column has not been
244 * set for <i>rowset</i>, or (3) <i>rowset</i>
245 * violates the active <code>JOIN</code>
246 * @see Joinable#setMatchColumn
247 */
248 public void addRowSet(Joinable rowset) throws SQLException;
249
250 /**
251 * Adds the given <code>RowSet</code> object to this <code>JoinRowSet</code>
252 * object and sets the designated column as the match column for
253 * the <code>RowSet</code> object. If the <code>RowSet</code> object
254 * is the first to be added to this <code>JoinRowSet</code>
255 * object, it forms the basis of the <code>JOIN</code> relationship to be
256 * established.
257 * <P>
258 * This method should be used when <i>RowSet</i> does not already have a match
259 * column set.
260 *
261 * @param rowset the <code>RowSet</code> object that is to be added to this
262 * <code>JoinRowSet</code> object; it may implement the
263 * <code>Joinable</code> interface
264 * @param columnIdx an <code>int</code> that identifies the column to become the
265 * match column
266 * @throws SQLException if (1) <i>rowset</i> is an empty rowset or
267 * (2) <i>rowset</i> violates the active <code>JOIN</code>
268 * @see Joinable#unsetMatchColumn
269 */
270 public void addRowSet(RowSet rowset, int columnIdx) throws SQLException;
271
272 /**
273 * Adds <i>rowset</i> to this <code>JoinRowSet</code> object and
274 * sets the designated column as the match column. If <i>rowset</i>
275 * is the first to be added to this <code>JoinRowSet</code>
276 * object, it forms the basis for the <code>JOIN</code> relationship to be
277 * established.
278 * <P>
279 * This method should be used when the given <code>RowSet</code> object
280 * does not already have a match column.
281 *
282 * @param rowset the <code>RowSet</code> object that is to be added to this
283 * <code>JoinRowSet</code> object; it may implement the
284 * <code>Joinable</code> interface
285 * @param columnName the <code>String</code> object giving the name of the
286 * column to be set as the match column
287 * @throws SQLException if (1) <i>rowset</i> is an empty rowset or
288 * (2) the match column for <i>rowset</i> does not satisfy the
289 * conditions of the <code>JOIN</code>
290 */
291 public void addRowSet(RowSet rowset,
292 String columnName) throws SQLException;
293
294 /**
295 * Adds one or more <code>RowSet</code> objects contained in the given
296 * array of <code>RowSet</code> objects to this <code>JoinRowSet</code>
297 * object and sets the match column for
298 * each of the <code>RowSet</code> objects to the match columns
299 * in the given array of column indexes. The first element in
300 * <i>columnIdx</i> is set as the match column for the first
301 * <code>RowSet</code> object in <i>rowset</i>, the second element of
302 * <i>columnIdx</i> is set as the match column for the second element
303 * in <i>rowset</i>, and so on.
304 * <P>
305 * The first <code>RowSet</code> object added to this <code>JoinRowSet</code>
306 * object forms the basis for the <code>JOIN</code> relationship.
307 * <P>
308 * This method should be used when the given <code>RowSet</code> object
309 * does not already have a match column.
310 *
311 * @param rowset an array of one or more <code>RowSet</code> objects
312 * to be added to the <code>JOIN</code>; it may implement the
313 * <code>Joinable</code> interface
314 * @param columnIdx an array of <code>int</code> values indicating the index(es)
315 * of the columns to be set as the match columns for the <code>RowSet</code>
316 * objects in <i>rowset</i>
317 * @throws SQLException if (1) an empty rowset is added to this
318 * <code>JoinRowSet</code> object, (2) a match column is not set
319 * for a <code>RowSet</code> object in <i>rowset</i>, or (3)
320 * a <code>RowSet</code> object being added violates the active
321 * <code>JOIN</code>
322 */
323 public void addRowSet(RowSet[] rowset,
324 int[] columnIdx) throws SQLException;
325
326 /**
327 * Adds one or more <code>RowSet</code> objects contained in the given
328 * array of <code>RowSet</code> objects to this <code>JoinRowSet</code>
329 * object and sets the match column for
330 * each of the <code>RowSet</code> objects to the match columns
331 * in the given array of column names. The first element in
332 * <i>columnName</i> is set as the match column for the first
333 * <code>RowSet</code> object in <i>rowset</i>, the second element of
334 * <i>columnName</i> is set as the match column for the second element
335 * in <i>rowset</i>, and so on.
336 * <P>
337 * The first <code>RowSet</code> object added to this <code>JoinRowSet</code>
338 * object forms the basis for the <code>JOIN</code> relationship.
339 * <P>
340 * This method should be used when the given <code>RowSet</code> object(s)
341 * does not already have a match column.
342 *
343 * @param rowset an array of one or more <code>RowSet</code> objects
344 * to be added to the <code>JOIN</code>; it may implement the
345 * <code>Joinable</code> interface
346 * @param columnName an array of <code>String</code> values indicating the
347 * names of the columns to be set as the match columns for the
348 * <code>RowSet</code> objects in <i>rowset</i>
349 * @throws SQLException if (1) an empty rowset is added to this
350 * <code>JoinRowSet</code> object, (2) a match column is not set
351 * for a <code>RowSet</code> object in <i>rowset</i>, or (3)
352 * a <code>RowSet</code> object being added violates the active
353 * <code>JOIN</code>
354 */
355 public void addRowSet(RowSet[] rowset,
356 String[] columnName) throws SQLException;
357
358 /**
359 * Returns a <code>Collection</code> object containing the
360 * <code>RowSet</code> objects that have been added to this
361 * <code>JoinRowSet</code> object.
362 * This should return the 'n' number of RowSet contained
363 * within the <code>JOIN</code> and maintain any updates that have occurred while in
364 * this union.
365 *
366 * @return a <code>Collection</code> object consisting of the
367 * <code>RowSet</code> objects added to this <code>JoinRowSet</code>
368 * object
369 * @throws SQLException if an error occurs generating the
370 * <code>Collection</code> object to be returned
371 */
372 public Collection<?> getRowSets() throws java.sql.SQLException;
373
374 /**
375 * Returns a <code>String</code> array containing the names of the
376 * <code>RowSet</code> objects added to this <code>JoinRowSet</code>
377 * object.
378 *
379 * @return a <code>String</code> array of the names of the
380 * <code>RowSet</code> objects in this <code>JoinRowSet</code>
381 * object
382 * @throws SQLException if an error occurs retrieving the names of
383 * the <code>RowSet</code> objects
384 * @see CachedRowSet#setTableName
385 */
386 public String[] getRowSetNames() throws java.sql.SQLException;
387
388 /**
389 * Creates a new <code>CachedRowSet</code> object containing the
390 * data in this <code>JoinRowSet</code> object, which can be saved
391 * to a data source using the <code>SyncProvider</code> object for
392 * the <code>CachedRowSet</code> object.
393 * <P>
394 * If any updates or modifications have been applied to the JoinRowSet
395 * the CachedRowSet returned by the method will not be able to persist
396 * it's changes back to the originating rows and tables in the
397 * in the datasource. The CachedRowSet instance returned should not
398 * contain modification data and it should clear all properties of
399 * it's originating SQL statement. An application should reset the
400 * SQL statement using the <code>RowSet.setCommand</code> method.
401 * <p>
402 * In order to allow changes to be persisted back to the datasource
403 * to the originating tables, the <code>acceptChanges</code> method
404 * should be used and called on a JoinRowSet object instance. Implementations
405 * can leverage the internal data and update tracking in their
406 * implementations to interact with the SyncProvider to persist any
407 * changes.
408 *
409 * @return a CachedRowSet containing the contents of the JoinRowSet
410 * @throws SQLException if an error occurs assembling the CachedRowSet
411 * object
412 * @see javax.sql.RowSet
413 * @see javax.sql.rowset.CachedRowSet
414 * @see javax.sql.rowset.spi.SyncProvider
415 */
416 public CachedRowSet toCachedRowSet() throws java.sql.SQLException;
417
418 /**
419 * Indicates if CROSS_JOIN is supported by a JoinRowSet
420 * implementation
421 *
422 * @return true if the CROSS_JOIN is supported; false otherwise
423 */
424 public boolean supportsCrossJoin();
425
426 /**
427 * Indicates if INNER_JOIN is supported by a JoinRowSet
428 * implementation
429 *
430 * @return true is the INNER_JOIN is supported; false otherwise
431 */
432 public boolean supportsInnerJoin();
433
434 /**
435 * Indicates if LEFT_OUTER_JOIN is supported by a JoinRowSet
436 * implementation
437 *
438 * @return true is the LEFT_OUTER_JOIN is supported; false otherwise
439 */
440 public boolean supportsLeftOuterJoin();
441
442 /**
443 * Indicates if RIGHT_OUTER_JOIN is supported by a JoinRowSet
444 * implementation
445 *
446 * @return true is the RIGHT_OUTER_JOIN is supported; false otherwise
447 */
448 public boolean supportsRightOuterJoin();
449
450 /**
451 * Indicates if FULL_JOIN is supported by a JoinRowSet
452 * implementation
453 *
454 * @return true is the FULL_JOIN is supported; false otherwise
455 */
456 public boolean supportsFullJoin();
457
458 /**
459 * Allow the application to adjust the type of <code>JOIN</code> imposed
460 * on tables contained within the JoinRowSet object instance.
461 * Implementations should throw a SQLException if they do
462 * not support a given <code>JOIN</code> type.
463 *
464 * @param joinType the standard JoinRowSet.XXX static field definition
465 * of a SQL <code>JOIN</code> to re-configure a JoinRowSet instance on
466 * the fly.
467 * @throws SQLException if an unsupported <code>JOIN</code> type is set
468 * @see #getJoinType
469 */
470 public void setJoinType(int joinType) throws SQLException;
471
472 /**
473 * Return a SQL-like description of the WHERE clause being used
474 * in a JoinRowSet object. An implementation can describe
475 * the WHERE clause of the SQL <code>JOIN</code> by supplying a SQL
476 * strings description of <code>JOIN</code> or provide a textual
477 * description to assist applications using a <code>JoinRowSet</code>
478 *
479 * @return whereClause a textual or SQL description of the logical
480 * WHERE clause used in the JoinRowSet instance
481 * @throws SQLException if an error occurs in generating a representation
482 * of the WHERE clause.
483 */
484 public String getWhereClause() throws SQLException;
485
486 /**
487 * Returns a <code>int</code> describing the set SQL <code>JOIN</code> type
488 * governing this JoinRowSet instance. The returned type will be one of
489 * standard JoinRowSet types: <code>CROSS_JOIN</code>, <code>INNER_JOIN</code>,
490 * <code>LEFT_OUTER_JOIN</code>, <code>RIGHT_OUTER_JOIN</code> or
491 * <code>FULL_JOIN</code>.
492 *
493 * @return joinType one of the standard JoinRowSet static field
494 * definitions of a SQL <code>JOIN</code>. <code>JoinRowSet.INNER_JOIN</code>
495 * is returned as the default <code>JOIN</code> type is no type has been
496 * explicitly set.
497 * @throws SQLException if an error occurs determining the SQL <code>JOIN</code>
498 * type supported by the JoinRowSet instance.
499 * @see #setJoinType
500 */
501 public int getJoinType() throws SQLException;
502
503 /**
504 * An ANSI-style <code>JOIN</code> providing a cross product of two tables
505 */
506 public static int CROSS_JOIN = 0;
507
508 /**
509 * An ANSI-style <code>JOIN</code> providing a inner join between two tables. Any
510 * unmatched rows in either table of the join should be discarded.
511 */
512 public static int INNER_JOIN = 1;
513
514 /**
515 * An ANSI-style <code>JOIN</code> providing a left outer join between two
516 * tables. In SQL, this is described where all records should be
517 * returned from the left side of the JOIN statement.
518 */
519 public static int LEFT_OUTER_JOIN = 2;
520
521 /**
522 * An ANSI-style <code>JOIN</code> providing a right outer join between
523 * two tables. In SQL, this is described where all records from the
524 * table on the right side of the JOIN statement even if the table
525 * on the left has no matching record.
526 */
527 public static int RIGHT_OUTER_JOIN = 3;
528
529 /**
530 * An ANSI-style <code>JOIN</code> providing a a full JOIN. Specifies that all
531 * rows from either table be returned regardless of matching
532 * records on the other table.
533 */
534 public static int FULL_JOIN = 4;
535
536
537 }