RdbQueryLeaf


1   /**
2    * MEDOR: Middleware Enabling Distributed Object Requests
3    *
4    * Copyright (C) 2001-2003 France Telecom R&D
5    * Contact: alexandre.lefebvre@rd.francetelecom.com
6    *
7    * This library is free software; you can redistribute it and/or
8    * modify it under the terms of the GNU Lesser General Public
9    * License as published by the Free Software Foundation; either
10   * version 2.1 of the License, or (at your option) any later version.
11   *
12   * This library is distributed in the hope that it will be useful,
13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15   * Lesser General Public License for more details.
16   *
17   * You should have received a copy of the GNU Lesser General Public
18   * License along with this library; if not, write to the Free Software
19   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20   *
21   * Initial developers: M. Alia, S. Chassande-Barrioz, A. Lefebvre
22   */
23  
24  package org.objectweb.medor.query.rdb.api;
25  
26  import org.objectweb.medor.query.api.QueryLeaf;
27  import org.objectweb.medor.api.MedorException;
28  import org.objectweb.medor.expression.api.ParameterOperand;
29  import org.objectweb.medor.expression.api.ExpressionException;
30  
31  import java.util.ArrayList  ;
32  
33  /**
34   * An RdbQueryLeaf represents a query leaf which encapsulates access to a
35   * relational database.
36   * <p>
37   * A SQL query is associated to an RdbQueryLeaf.
38   * @see org.objectweb.medor.query.rdb.api.RdbExpQueryLeaf
39   * @see org.objectweb.medor.query.rdb.api.RdbStringQueryLeaf
40   *
41   * @author Sebastien Chassande-Barrioz
42   */
43  public interface RdbQueryLeaf extends QueryLeaf {
44  
45      /**
46       * Returns the associated SQL queryn giving the list of SELECT fields
47       * as an input parameter.
48       * <p>In the case of an RdbExpQueryLeaf, the query is computed.
49       * @param pos is an array of ParameterOperand
50       * @param selectFields is the input Array of fields for constructing the
51       * SELECT clause.
52       * @param rangeStartAt is true for range queries where the first row to be 
53       * returned in the case of a range query is greater than 0.
54       * @param rangeSize is true for range queries where the number of rows to be 
55       * returned in the case of a range query is less than Integer.MAXVALUE
56       * @return the SQL query associated to the RdbQueryLeaf, as a String.
57       * @throws MedorException in the case of RdbExpQueryLeaves if the
58       * SQL request cannot be computed from the associated Expression
59       */
60      String   getSqlRequest(ParameterOperand[] pos,
61                           ArrayList   selectFields,
62                           boolean rangeStartAt,
63                           boolean rangeSize)
64              throws MedorException, ExpressionException;
65  
66      /**
67       * Returns the associated SQL query.
68       * <p>In the case of an RdbExpQueryLeaf, the query is computed.
69       * @param pos is an array of ParameterOperand
70       * @param rangeStartAt is true for range queries where the first row to be 
71       * returned in the case of a range query is greater than 0.
72       * @param rangeSize is true for range queries where the number of rows to be 
73       * returned in the case of a range query is less than Integer.MAXVALUE
74       * @return the SQL query associated to the RdbQueryLeaf, as a String.
75       * @throws MedorException in the case of RdbExpQueryLeaves if the
76       * SQL request cannot be computed from the associated Expression
77       */
78      String   getSqlRequest(ParameterOperand[] pos,
79              boolean rangeStartAt,
80              boolean rangeSize)
81              throws MedorException, ExpressionException;
82  
83      /**
84       * Builds the SELECT clause of the query (without "SELECT ").
85       * @param selectList is the start of the SELECT clause to which the list
86       * of qualified columns is appended.
87       * @param selectFields is the fields for the SELECT clause. Such fields can
88       * either be plain fields, or can be aggregate fields
89       * @param qualified indicates whether the field names should be qualified
90       * with the table name or not.
91       * @return the list of qualified columns for the SELECT clause
92       */
93      String   getSelectList(String   selectList, ArrayList   selectFields,
94                           boolean qualified)
95              throws MedorException;
96  
97      /**
98       * Is the current query leaf a subquery (in particular for the case of
99       * aggregates).
100      * @return true if the current RdbExpQueryLeaf is a subquery
101      */
102     boolean isSubquery();
103 
104     /**
105      * Indicates whether the current RdbExpQueryLeaf is a subquery of another
106      * Rdb query leaf (in particular in the case of subqueries).
107      * <p>The default value is false.</p>
108      * @param subquery is true when the current RdbExpQueryLeaf is a subquery
109      * of another Rdb query leaf/node, false otherwise.
110      */
111     void setIsSubquery(boolean subquery);
112 }
113
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