1 package org.apache.torque;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 /**
23 * The metadata of a column (or pseudocolumn) in a database.
24 *
25 * @version $Id: Column.java 1335473 2012-05-08 12:35:24Z tfischer $
26 */
27 public interface Column
28 {
29 /**
30 * Returns the name of the database column (not prefixed by the table name).
31 *
32 * @return the name of the column, may be null.
33 * (e.g. for the pseudocoulumn count(*)).
34 * Is not blank.
35 */
36 String getColumnName();
37
38 /**
39 * Returns the name of the associated table
40 * (not prefixed by the schema name).
41 *
42 * @return the name of the table, may be null but not blank.
43 */
44 String getTableName();
45
46 /**
47 * Returns the name of any fixed schema prefix for the column's table
48 * (if any).
49 *
50 * @return the schema name, or null if the schema is not known.
51 */
52 String getSchemaName();
53
54 /**
55 * Returns the table name prefixed with the schema name if it exists.
56 * I.e. if a schema name exists, the result will be schemaName.tableName,
57 * and otherwise it will just be tableName.
58 *
59 * @return the fully qualified table name of the column,
60 * may be null but not blank.
61 */
62 String getFullTableName();
63
64 /**
65 * Returns the SQL expression for the column, qualified by the
66 * table name but not by the schema name.
67 * This can also be a pseudocolumn (e.g. count(*)).
68 *
69 * @return the SQL expression for the column, not null.
70 */
71 String getSqlExpression();
72 }