1 package org.odmg;
2
3
4
5 /**
6
7 * The interface to an OQL query object.
8
9 * @author David Jordan (as Java Editor of the Object Data Management Group)
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11 * @version ODMG 3.0
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13 */
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15
16
17 public interface OQLQuery
18
19 {
20
21
22
23 /**
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25 * Create an OQL query from the string parameter.
26
27 * In order to execute a query, an <code>OQLQuery</code> object must be created
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29 * by calling <code>Implementation.newOQLQuery</code>, then calling the
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31 * <code>create</code> method with the query string.
32
33 * The <code>create</code> method might throw <code>QueryInvalidException</code>
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35 * if the query could not be compiled properly. Some implementations may not want
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37 * to compile the query before <code>execute</code> is called. In this case
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39 * <code>QueryInvalidException</code> is thrown when <code>execute</code> is called.
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41 * @param query An OQL query.
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43 * @exception QueryInvalidException The query syntax is invalid.
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45 */
46
47 public void create(String query) throws QueryInvalidException;
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49
50
51 /**
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53 * Bind a parameter to the query.
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55 * A parameter is denoted in the query string passed to <code>create</code> by <i>$i</i>,
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57 * where <i>i</i> is the rank of the parameter, beginning with 1.
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59 * The parameters are set consecutively by calling this method <code>bind</code>.
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61 * The <i>ith</i> variable is set by the <i>ith</i> call to the <code>bind</code> method.
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63 * If any of the <i>$i</i> are not set by a call to <code>bind</code> at the point
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65 * <code>execute</code> is called, <code>QueryParameterCountInvalidException</code> is thrown.
66
67 * The parameters must be objects, and the result is an <code>Object</code>.
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69 * Objects must be used instead of primitive types (<code>Integer</code> instead
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71 * of <code>int</code>) for passing the parameters.
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73 * <p>
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75 * If the parameter is of the wrong type,
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77 * <code>QueryParameterTypeInvalidException</code> is thrown.
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79 * After executing a query, the parameter list is reset.
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81 * @parameter A value to be substituted for a query parameter.
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83 * @exception QueryParameterCountInvalidException The number of calls to
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85 * <code>bind</code> has exceeded the number of parameters in the query.
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87 * @exception QueryParameterTypeInvalidException The type of the parameter does
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89 * not correspond with the type of the parameter in the query.
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91 */
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93 public void bind(Object parameter) throws QueryParameterCountInvalidException,
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95 QueryParameterTypeInvalidException;
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97
98
99 /**
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101 * Execute the query.
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103 * After executing a query, the parameter list is reset.
104
105 * Some implementations may throw additional exceptions that are also derived
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107 * from <code>ODMGException</code>.
108
109 * @return The object that represents the result of the query.
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111 * The returned data, whatever its OQL type, is encapsulated into an object.
112
113 * For instance, when OQL returns an integer, the result is put into an
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115 * <code>Integer</code> object. When OQL returns a collection (literal or object),
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117 * the result is always a Java collection object of the same kind
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119 * (for instance, a <code>DList</code>).
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121 * @exception QueryException An exception has occurred while executing the query.
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123 */
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125 public Object execute() throws QueryException;
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127 }
128