我正在尝试了解使用 JDBC 从 Oracle 存储过程/函数获取表数据的不同方法.六种方式如下:
I'm trying to understand different ways of getting table data from Oracle stored procedures / functions using JDBC. The six ways are the following ones:
以下是 PL/SQL 中的一些示例:
Here are some examples in PL/SQL:
-- schema-level table type
CREATE TYPE t_type AS OBJECT (val VARCHAR(4));
CREATE TYPE t_table AS TABLE OF t_type;
CREATE OR REPLACE PACKAGE t_package AS
-- package level table type
TYPE t_table IS TABLE OF some_table%rowtype;
-- package level cursor type
TYPE t_cursor IS REF CURSOR;
END library_types;
-- and example procedures:
CREATE PROCEDURE p_1 (result OUT t_table);
CREATE PROCEDURE p_2 (result OUT t_package.t_table);
CREATE PROCEDURE p_3 (result OUT t_package.t_cursor);
CREATE FUNCTION f_4 RETURN t_table;
CREATE FUNCTION f_5 RETURN t_package.t_table;
CREATE FUNCTION f_6 RETURN t_package.t_cursor;
我已经成功地使用 JDBC 调用了 3、4 和 6:
I have succeeded in calling 3, 4, and 6 with JDBC:
// Not OK: p_1 and p_2
CallableStatement call = connection.prepareCall("{ call p_1(?) }");
call.registerOutParameter(1, OracleTypes.CURSOR);
call.execute(); // Raises PLS-00306. Obviously CURSOR is the wrong type
// OK: p_3
CallableStatement call = connection.prepareCall("{ call p_3(?) }");
call.registerOutParameter(1, OracleTypes.CURSOR);
call.execute();
ResultSet rs = (ResultSet) call.getObject(1); // Cursor results
// OK: f_4
PreparedStatement stmt = connection.prepareStatement("select * from table(f_4)");
ResultSet rs = stmt.executeQuery();
// Not OK: f_5
PreparedStatement stmt = connection.prepareStatement("select * from table(f_5)");
stmt.executeQuery(); // Raises ORA-00902: Invalid data type
// OK: f_6
CallableStatement call = connection.prepareCall("{ ? = call f_6 }");
call.registerOutParameter(1, OracleTypes.CURSOR);
call.execute();
ResultSet rs = (ResultSet) call.getObject(1); // Cursor results
很明显，我在理解上有困难
So obviously, I'm having trouble understanding
我似乎找不到任何关于此的文档，因为每个人都总是使用游标而不是表类型.也许是因为不可能?不过，我更喜欢表类型，因为它们是正式定义的，可以使用字典视图(至少是模式级表类型)发现.
I can't seem to find any documentation on this, as everyone always uses cursors instead of table types. Maybe because it's not possible? I prefer table types, though, because they are formally defined and can be discovered using the dictionary views (at least the schema-level table types).
注意:显然，我可以编写一个包装函数来返回 OUT 参数和包级表类型.但我更喜欢干净的解决方案.
Note: obviously, I could write a wrapper function returning the OUT parameters and package-level table types. But I'd prefer the clean solution.
您无法从 java 访问 PLSQL 对象(案例 2 & 5 = 包级对象)，请参阅 "java - 在 oracle 存储过程中传递数组".但是，您可以访问 SQL 类型(案例 1 和 4).
You can't access PLSQL objects (cases 2 & 5 = package-level objects) from java, see "java - passing array in oracle stored procedure". You can however access SQL types (case 1 and 4).
从PL/SQL中获取OUT参数到java，可以使用Tom Kyte 的一个线程 使用 OracleCallableStatement.由于您检索的是 Object 表而不是 VARCHAR 表，因此您的代码将有一个额外的步骤.
To get OUT parameters from PL/SQL to java, you can use the method described in one of Tom Kyte's thread using OracleCallableStatement. Your code will have an additional step since you're retrieving a table of Object instead of a table of VARCHAR.
这是一个使用 SQL 对象表的演示，首先是设置:
Here's a demo using Table of SQL Object, first the setup:
SQL> CREATE TYPE t_type AS OBJECT (val VARCHAR(4));
2 /
Type created
SQL> CREATE TYPE t_table AS TABLE OF t_type;
2 /
Type created
SQL> CREATE OR REPLACE PROCEDURE p_sql_type (p_out OUT t_table) IS
2 BEGIN
3 p_out := t_table(t_type('a'), t_type('b'));
4 END;
5 /
Procedure created
实际的java类(使用dbms_output.put_line来记录，因为我将从SQL调用它，如果从java调用则使用System.out.println):
The actual java class (using dbms_output.put_line to log because I will call it from SQL, use System.out.println if called from java):
SQL> CREATE OR REPLACE
2 AND COMPILE JAVA SOURCE NAMED "ArrayDemo"
3 as
4 import java.sql.*;
5 import oracle.sql.*;
6 import oracle.jdbc.driver.*;
7
8 public class ArrayDemo {
9
10 private static void log(String s) throws SQLException {
11 PreparedStatement ps =
12 new OracleDriver().defaultConnection().prepareStatement
13 ( "begin dbms_output.put_line(:x); end;" );
14 ps.setString(1, s);
15 ps.execute();
16 ps.close();
17 }
18
19 public static void getArray() throws SQLException {
20
21 Connection conn = new OracleDriver().defaultConnection();
22
23 OracleCallableStatement cs =
24 (OracleCallableStatement)conn.prepareCall
25 ( "begin p_sql_type(?); end;" );
26 cs.registerOutParameter(1, OracleTypes.ARRAY, "T_TABLE");
27 cs.execute();
28 ARRAY array_to_pass = cs.getARRAY(1);
29
30 /*showing content*/
31 Datum[] elements = array_to_pass.getOracleArray();
32
33 for (int i=0;i<elements.length;i++){
34 Object[] element = ((STRUCT) elements[i]).getAttributes();
35 String value = (String)element[0];
36 log("array(" + i + ").val=" + value);
37 }
38 }
39 }
40 /
Java created
让我们称之为:
SQL> CREATE OR REPLACE
2 PROCEDURE show_java_calling_plsql
3 AS LANGUAGE JAVA
4 NAME 'ArrayDemo.getArray()';
5 /
Procedure created
SQL> EXEC show_java_calling_plsql;
array(0).val=a
array(1).val=b
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