Column


1   /*
2    * The contents of this file are subject to the terms 
3    * of the Common Development and Distribution License 
4    * (the License).  You may not use this file except in
5    * compliance with the License.
6    * 
7    * You can obtain a copy of the license at 
8    * https://glassfish.dev.java.net/public/CDDLv1.0.html or
9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
10   * See the License for the specific language governing 
11   * permissions and limitations under the License.
12   * 
13   * When distributing Covered Code, include this CDDL 
14   * Header Notice in each file and include the License file 
15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
16   * If applicable, add the following below the CDDL Header, 
17   * with the fields enclosed by brackets [] replaced by
18   * you own identifying information: 
19   * "Portions Copyrighted [year] [name of copyright owner]"
20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  package javax.persistence;
24  
25  import java.lang.annotation.Target  ;
26  import java.lang.annotation.Retention  ;
27  import static java.lang.annotation.ElementType.METHOD  ;
28  import static java.lang.annotation.ElementType.FIELD  ;
29  import static java.lang.annotation.RetentionPolicy.RUNTIME  ;
30  
31  /**
32   * Is used to specify a mapped column for a persistent property or field.
33   * If no Column annotation is specified, the default values are applied.
34   * <p> Examples:
35   *
36   * <blockquote><pre>
37   * Example 1:
38   * &#064;Column(name="DESC", nullable=false, length=512)
39   * public String getDescription() { return description; }
40   *
41   * Example 2:
42   * &#064;Column(name="DESC",
43   *         columnDefinition="CLOB NOT NULL",
44   *         table="EMP_DETAIL")
45   * &#064;Lob
46   * public String getDescription() { return description; }
47   *
48   * Example 3:
49   * &#064;Column(name="ORDER_COST", updatable=false, precision=12, scale=2)
50   * public BigDecimal getCost() { return cost; }
51   *
52   * </pre></blockquote>
53   *
54   *
55   * @since Java Persistence 1.0
56   */ 
57  @Target  ({METHOD, FIELD}) 
58  @Retention  (RUNTIME)
59  public @interface Column {
60  
61      /**
62       * (Optional) The name of the column. Defaults to 
63       * the property or field name.
64       */
65      String   name() default "";
66  
67      /**
68       * (Optional) Whether the property is a unique key.  This is a 
69       * shortcut for the UniqueConstraint annotation at the table 
70       * level and is useful for when the unique key constraint is 
71       * only a single field. This constraint applies in addition 
72       * to any constraint entailed by primary key mapping and 
73       * to constraints specified at the table level.
74       */
75      boolean unique() default false;
76  
77      /**
78       * (Optional) Whether the database column is nullable.
79       */
80      boolean nullable() default true;
81  
82      /**
83       * (Optional) Whether the column is included in SQL INSERT 
84       * statements generated by the persistence provider.
85       */
86      boolean insertable() default true;
87  
88      /**
89       * (Optional) Whether the column is included in SQL UPDATE 
90       * statements generated by the persistence provider.
91       */
92      boolean updatable() default true;
93  
94      /**
95       * (Optional) The SQL fragment that is used when 
96       * generating the DDL for the column.
97       * <p> Defaults to the generated SQL to create a
98       * column of the inferred type.
99       */
100     String   columnDefinition() default "";
101 
102     /**
103      * (Optional) The name of the table that contains the column. 
104      * If absent the column is assumed to be in the primary table.
105      */
106     String   table() default "";
107 
108     /**
109      * (Optional) The column length. (Applies only if a
110      * string-valued column is used.)
111      */
112     int length() default 255;
113 
114     /**
115      * (Optional) The precision for a decimal (exact numeric) 
116      * column. (Applies only if a decimal column is used.)
117      * Value must be set by developer if used when generating 
118      * the DDL for the column.
119      */
120     int precision() default 0;
121 
122     /**
123      * (Optional) The scale for a decimal (exact numeric) column. 
124      * (Applies only if a decimal column is used.)
125      */
126     int scale() default 0;
127 }
128
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