Oracle SQL - 如何使用 JSP 调用 ODCI 流水线函数

Question

以下是具体的实现 https://docs.oracle.com/cd/B28359_01/appdev.111/b28425/pipelined_example.htm#CHDHDHEE

假设我们有以下 table 定义：

CREATE TABLE StockTable (
  ticker VARCHAR(4),
  openprice NUMBER,
  closeprice NUMBER
);

然后，我们得到了以下类型（一个基本类型作为对象，一个类型作为它的table）：

CREATE TYPE TickerType AS OBJECT
(
  ticker VARCHAR2(4),
  PriceType VARCHAR2(1),
   price NUMBER
);
/

CREATE TYPE TickerTypeSet AS TABLE OF TickerType;

另外，我们定义了一个 ODCI 类型，它在 SQL 和 Java 数据库中的存储过程中实现：

SQL:

CREATE OR REPLACE TYPE StockPivotImpl AS OBJECT
(
  key INTEGER,

  STATIC FUNCTION ODCITableStart(sctx OUT StockPivotImpl, cur SYS_REFCURSOR)
    RETURN NUMBER
    AS LANGUAGE JAVA
    NAME 'StockPivotImpl.ODCITableStart(oracle.sql.STRUCT[], java.sql.ResultSet) return java.math.BigDecimal',

  MEMBER FUNCTION ODCITableFetch(self IN OUT StockPivotImpl, nrows IN NUMBER,
                                 outSet OUT TickerTypeSet) RETURN NUMBER
    AS LANGUAGE JAVA
    NAME 'StockPivotImpl.ODCITableFetch(java.math.BigDecimal, oracle.sql.ARRAY[]) return java.math.BigDecimal',

  MEMBER FUNCTION ODCITableClose(self IN StockPivotImpl) RETURN NUMBER
    AS LANGUAGE JAVA
    NAME 'StockPivotImpl.ODCITableClose() return java.math.BigDecimal'

);
/

Java 存储过程：

import java.io.*;
import java.util.*;
import oracle.sql.*;
import java.sql.*;
import java.math.BigDecimal;
import oracle.CartridgeServices.*;

// stored context type

public class StoredCtx
{
  ResultSet rset;
  public StoredCtx(ResultSet rs) { rset=rs; }
}

// implementation type

public class StockPivotImpl implements SQLData 
{
  private BigDecimal key;

  final static BigDecimal SUCCESS = new BigDecimal(0);
  final static BigDecimal ERROR = new BigDecimal(1);

  // Implement SQLData interface.

  String sql_type;
  public String getSQLTypeName() throws SQLException 
  {
    return sql_type;
  }

  public void readSQL(SQLInput stream, String typeName) throws SQLException 
  {
    sql_type = typeName;
    key = stream.readBigDecimal();
  }

  public void writeSQL(SQLOutput stream) throws SQLException 
  {
    stream.writeBigDecimal(key);
  }

  // type methods implementing ODCITable interface

  static public BigDecimal ODCITableStart(STRUCT[] sctx,ResultSet rset)
    throws SQLException 
  {
    Connection conn = DriverManager.getConnection("jdbc:default:connection:");

    // create a stored context and store the result set in it
    StoredCtx ctx=new StoredCtx(rset);

    // register stored context with cartridge services
    int key;
    try {
      key = ContextManager.setContext(ctx);
    } catch (CountException ce) {
      return ERROR;
    }

    // create a StockPivotImpl instance and store the key in it
    Object[] impAttr = new Object[1];
    impAttr[0] = new BigDecimal(key); 
    StructDescriptor sd = new StructDescriptor("STOCKPIVOTIMPL",conn);
    sctx[0] = new STRUCT(sd,conn,impAttr);

    return SUCCESS;
  }

  public BigDecimal ODCITableFetch(BigDecimal nrows, ARRAY[] outSet)
    throws SQLException 
  {
    Connection conn = DriverManager.getConnection("jdbc:default:connection:");

    // retrieve stored context using the key
    StoredCtx ctx;
    try {
      ctx=(StoredCtx)ContextManager.getContext(key.intValue());
    } catch (InvalidKeyException ik ) {
      return ERROR;
    }

    // get the nrows parameter, but return up to 10 rows
    int nrowsval = nrows.intValue();
    if (nrowsval>10) nrowsval=10;

    // create a vector for the fetched rows
    Vector v = new Vector(nrowsval);
    int i=0;

    StructDescriptor outDesc = 
      StructDescriptor.createDescriptor("TICKERTYPE", conn);
    Object[] out_attr = new Object[3];

    while(nrowsval>0 && ctx.rset.next()){
      out_attr[0] = (Object)ctx.rset.getString(1);
      out_attr[1] = (Object)new String("O");
      out_attr[2] = (Object)new BigDecimal(ctx.rset.getFloat(2));
      v.add((Object)new STRUCT(outDesc, conn, out_attr));

      out_attr[1] = (Object)new String("C");
      out_attr[2] = (Object)new BigDecimal(ctx.rset.getFloat(3));
      v.add((Object)new STRUCT(outDesc, conn, out_attr));

      i+=2;
      nrowsval-=2;
    }

    // return if no rows found
    if(i==0) return SUCCESS;

    // create the output ARRAY using the vector
    Object out_arr[] = v.toArray();
    ArrayDescriptor ad = new ArrayDescriptor("TICKERTYPESET",conn);
    outSet[0] = new ARRAY(ad,conn,out_arr);

    return SUCCESS;
  }

  public BigDecimal ODCITableClose() throws SQLException {

    // retrieve stored context using the key, and remove from ContextManager
    StoredCtx ctx;
    try {
      ctx=(StoredCtx)ContextManager.clearContext(key.intValue());
    } catch (InvalidKeyException ik ) {
      return ERROR;
    }

    // close the result set
    Statement stmt = ctx.rset.getStatement();
    ctx.rset.close();
    if(stmt!=null) stmt.close();

    return SUCCESS;
  }

}

在所有这一切之后，为了拥有一个可用于创建上述 table 类型的 table 的流水线函数，我们需要一个 ref光标 和 流水线函数本身 。我已经将 ref 游标放入一个包中。

-- Define the ref cursor type
  CREATE OR REPLACE PACKAGE refcur_pkg IS
    TYPE refcur_t IS REF CURSOR RETURN StockTable%ROWTYPE;
  END refcur_pkg;
/

  -- Create table function
  CREATE OR REPLACE FUNCTION StockPivot(p refcur_pkg.refcur_t) RETURN TickerTypeSet
  PIPELINED USING StockPivotImpl;
/

我的问题是如何调用 StockPivot 函数以执行 JSP 并显示上述类型的 table。

我希望从模拟 table:

的简单 select 中得到结果

-----------------------------
|  column1 |  column2 | ... |
|---------------------------|
| row_data1| row_data2| ... |
| --------------------------|
|___________________________|

我试过这样调用该函数，但由于显而易见的原因（我们需要一个引用游标作为参数），它无法正常工作：

SELECT * FROM TABLE(StockPivot());

提前致谢。

Answer 1

选项 1 为 return 强引用游标创建函数。

    create or replace function getCursor return refcur_pkg.refcur_t  is
             c_tmp refcur_pkg.refcur_t;
            begin 
             open c_tmp for select * from StockTable;
             return c_tmp;
            end;  

SELECT * FROM TABLE(StockPivot(getCursor()));

选项2。你可以试试游标表达式，应该也可以。 Cursor expression.

SELECT * FROM TABLE(StockPivot(Cursor(select * from StockTable)));

Oracle SQL - 如何使用 JSP 调用 ODCI 流水线函数

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sql

oracle

plsql

java-stored-procedures