使用多个结果集
Oracle 不支持批量查询，因此无法从一个命令返回多个结果集。使用存储过程时，返回多个结果集类似于返回单个结果集；必须使用 REF CURSOR 输出参数。要返回多个结果集，请使用多个 REF CURSOR 输出参数。
以下是返回两个结果集（全部 EMPLOYEES 和 JOBS 记录）的包规范：
CREATE OR new PACKAGE SELECT_EMPLOYEES_JOBS AS
TYPE T_CURSOR IS REF CURSOR;
PROCEDURE GetEmployeesAndJobs (
cur_Employees OUT T_CURSOR,
cur_Jobs OUT T_CURSOR
);
END SELECT_EMPLOYEES_JOBS;
包正文如下所示：
CREATE OR new PACKAGE BODY SELECT_EMPLOYEES_JOBS AS
PROCEDURE GetEmployeesAndJobs
(
cur_Employees OUT T_CURSOR,
cur_Jobs OUT T_CURSOR
)
IS
BEGIN
-- return all EMPLOYEES records
OPEN cur_Employees FOR
SELECT * FROM Employees;
-- return all JOBS records
OPEN cur_Jobs FOR
SELECT * FROM Jobs;
END GetEmployeesAndJobs;
END SELECT_EMPLOYEES_JOBS;
以下代码显示了如何使用从上述包中返回的两个结果集来填充 DataSet 中的两个相关表：
// create the connection
OracleConnection conn = new OracleConnection("Data Source=oracledb;
User Id=UserID;Password=Password;");
// define the command for the stored procedure
OracleCommand cmd = new OracleCommand();
cmd.Connection = conn;
cmd.CommandText = "SELECT_EMPLOYEES_JOBS.GetEmployeesAndJobs";
// add the parameters including the two REF CURSOR types to retrieve
// the two result sets
cmd.Parameters.Add("cur_Employees", OracleType.Cursor).Direction =
ParameterDirection.Output;
cmd.Parameters.Add("cur_Jobs", OracleType.Cursor).Direction =
ParameterDirection.Output;
cmd.CommandType = CommandType.StoredProcedure;
// create the DataAdapter and map tables
OracleDataAdapter da = new OracleDataAdapter(cmd);
da.TableMappings.Add("Table", "EMPLOYEES");
da.TableMappings.Add("Table1", "JOBS");
// create and fill the DataSet
DataSet ds = new DataSet();
da.Fill(ds);
// create a relation
ds.Relations.Add("EMPLOYEES_JOBS_RELATION",
ds.Tables["JOBS"].Columns["JOB_ID"],
ds.Tables["EMPLOYEES"].Columns["JOB_ID"]);
// output the second employee (zero-based array) and job title
// based on the relation
Console.WriteLine("Employee ID: " +
ds.Tables["EMPLOYEES"].Rows[1]["EMPLOYEE_ID"] +
"; Job Title: " +
ds.Tables["EMPLOYEES"].Rows[1].GetParentRow(
"EMPLOYEES_JOBS_RELATION")["JOB_TITLE"]);
控制台输出显示了第二个员工的职务：
Employee ID: 101; Job Title: Administration Vice President
来自于:http://www.microsoft.com/china/MSDN/library/data/dataAccess/DMSDNorsps.mspx
遇到的错误：在开发时遇到了未处理的句柄错误，其原因是没有为所有的输出参数返回值。
