Return 显式游标的 SQL 语句
Return the SQL Statement of an Explicit Cursor
以 Oracle 论坛中显示的示例为例：Generating excel(xls) using plsql，我想从查询的数据集生成一个 excel 文件。
此处提供的示例有效。但是，我遇到了一些挑战：
- 我的 SQL 查询很长，超过了
VARCHAR2 4000 个字符的限制。
- 我想将参数传递给我的查询。
- 我想以一种非常简单的方式完成它，而不使用动态 SQL（如果可能的话）。
我得出的结果如下所示：
包定义：
create or replace package tabletoexcel
as
PROCEDURE run_query(p_fh IN UTL_FILE.FILE_TYPE
, p_cur IN SYS_REFCURSOR);
PROCEDURE start_workbook (p_fh IN UTL_FILE.FILE_TYPE);
PROCEDURE end_workbook (p_fh IN UTL_FILE.FILE_TYPE);
PROCEDURE start_worksheet(p_fh IN UTL_FILE.FILE_TYPE
, p_sheetname IN VARCHAR2);
PROCEDURE end_worksheet (p_fh IN UTL_FILE.FILE_TYPE);
PROCEDURE set_date_style (p_fh IN UTL_FILE.FILE_TYPE);
end tabletoexcel;
create or replace package body tabletoexcel
as
PROCEDURE run_query(p_fh UTL_FILE.FILE_TYPE
, p_sql IN VARCHAR2) IS
v_v_val VARCHAR2(4000);
v_n_val NUMBER;
v_d_val DATE;
v_ret NUMBER;
c NUMBER;
d NUMBER;
col_cnt INTEGER;
f BOOLEAN;
rec_tab DBMS_SQL.DESC_TAB;
col_num NUMBER;
BEGIN
c := DBMS_SQL.OPEN_CURSOR;
-- parse the SQL statement
DBMS_SQL.PARSE(c, p_sql, DBMS_SQL.NATIVE);
-- start execution of the SQL statement
d := DBMS_SQL.EXECUTE(c);
-- get a description of the returned columns
DBMS_SQL.DESCRIBE_COLUMNS(c, col_cnt, rec_tab);
-- bind variables to columns
FOR j in 1..col_cnt
LOOP
CASE rec_tab(j).col_type
WHEN 1 THEN DBMS_SQL.DEFINE_COLUMN(c,j,v_v_val,4000);
WHEN 2 THEN DBMS_SQL.DEFINE_COLUMN(c,j,v_n_val);
WHEN 12 THEN DBMS_SQL.DEFINE_COLUMN(c,j,v_d_val);
ELSE
DBMS_SQL.DEFINE_COLUMN(c,j,v_v_val,4000);
END CASE;
END LOOP;
-- Output the column headers
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Row>');
FOR j in 1..col_cnt
LOOP
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="String">'||rec_tab(j).col_name||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
END LOOP;
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Row>');
-- Output the data
LOOP
v_ret := DBMS_SQL.FETCH_ROWS(c);
EXIT WHEN v_ret = 0;
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Row>');
FOR j in 1..col_cnt
LOOP
CASE rec_tab(j).col_type
WHEN 1 THEN DBMS_SQL.COLUMN_VALUE(c,j,v_v_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="String">'||v_v_val||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
WHEN 2 THEN DBMS_SQL.COLUMN_VALUE(c,j,v_n_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="Number">'||to_char(v_n_val)||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
WHEN 12 THEN DBMS_SQL.COLUMN_VALUE(c,j,v_d_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell ss:StyleID="OracleDate">');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="DateTime">'||to_char(v_d_val,'YYYY-MM-DD"T"HH24:MI:SS')||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
ELSE
DBMS_SQL.COLUMN_VALUE(c,j,v_v_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="String">'||v_v_val||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
END CASE;
END LOOP;
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Row>');
END LOOP;
DBMS_SQL.CLOSE_CURSOR(c);
END run_query;
PROCEDURE start_workbook (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'<?xml version="1.0"?>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Workbook xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet">');
END start_workbook;
PROCEDURE end_workbook (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Workbook>');
END end_workbook;
--
PROCEDURE start_worksheet(p_fh UTL_FILE.FILE_TYPE
, p_sheetname IN VARCHAR2) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Worksheet ss:Name="'||p_sheetname||'">');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Table>');
END start_worksheet;
PROCEDURE end_worksheet (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Table>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Worksheet>');
END end_worksheet;
--
PROCEDURE set_date_style (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Styles>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Style ss:ID="OracleDate">');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:NumberFormat ss:Format="dd/mm/yyyy\ hh:mm:ss"/>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Style>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Styles>');
END set_date_style;
end tabletoexcel;
现在，我的匿名块最好像下面这样（请注意评论）：
declare
l_fh UTL_FILE.FILE_TYPE;
l_directory VARCHAR2(30) := 'EMPLOYEE_FILE_DIR';
l_filename VARCHAR2(30) := 'myfile.xls';
l_sql_statement VARCHAR2(4000);
Cursor emp_cur (p_emp_no varchar2
,p_payroll_id number
,p_bg_id number)
is
select *
from table_a
where employee_number = nvl(p_emp_no, employee_number)
and payroll_id = nvl(p_payroll_id, payroll_id);
and business_group_id = p_bg_id
-- This is the Really really long query but i just placed Table_A for Sample Purposes
BEGIN
l_fh := UTl_file.FOPEN(upper(l_directory),l_filename,'w',32767);
tabletoexcel.start_workbook (l_fh);
tabletoexcel.set_date_style (l_fh);
tabletoexcel.start_worksheet(l_fh, 'EMP');
tabletoexcel.run_query(emp_cur('1', 2, 3));
-- I'm sure this won't work, but i would like to pass something simple as this.
tabletoexcel.end_worksheet (l_fh);
tabletoexcel.end_workbook (l_fh);
UTl_file.FCLOSE(l_fh);
END;
是否可以将显式游标定义传递给 DBMS_SQL 包？
我在考虑 Returns 显式游标的 SQL 语句的内置函数可以解决这个问题。也许是参考光标？
是的，您可以使用 DBMS_SQL.TO_CURSOR_NUMBER 函数来做到这一点。您的程序将如下所示：
PROCEDURE run_query(p_cur IN OUT SYS_REFCURSOR) IS
...
BEGIN
c := DBMS_SQL.TO_CURSOR_NUMBER(p_cur);
-- get a description of the returned columns
DBMS_SQL.DESCRIBE_COLUMNS(c, col_cnt, rec_tab);
...
然后你必须这样称呼它：
declare
l_cur SYS_REFCURSOR;
BEGIN
OPEN l_cur FOR
select *
from table_a
where employee_number = nvl(p_emp_no, employee_number)
and payroll_id = nvl(p_payroll_id, payroll_id);
and business_group_id = p_bg_id
...;
tabletoexcel.run_query(l_cur);
OPEN FOR 语句允许 CLOB 作为语句，因此在大小方面没有实际限制。
由于您在设计时不知道将选择哪些列（至少我是这么认为的），因此无法摆脱 DBMS_SQL.DESCRIBE_COLUMNS 和 DBMS_SQL.DEFINE_COLUMN。否则你可以使用 FETCH Statement 而不是 DBMS_SQL.FETCH_ROWS(c)
以 Oracle 论坛中显示的示例为例：Generating excel(xls) using plsql，我想从查询的数据集生成一个 excel 文件。
此处提供的示例有效。但是，我遇到了一些挑战：
- 我的 SQL 查询很长，超过了
VARCHAR24000 个字符的限制。 - 我想将参数传递给我的查询。
- 我想以一种非常简单的方式完成它，而不使用动态 SQL（如果可能的话）。
我得出的结果如下所示：
包定义：
create or replace package tabletoexcel
as
PROCEDURE run_query(p_fh IN UTL_FILE.FILE_TYPE
, p_cur IN SYS_REFCURSOR);
PROCEDURE start_workbook (p_fh IN UTL_FILE.FILE_TYPE);
PROCEDURE end_workbook (p_fh IN UTL_FILE.FILE_TYPE);
PROCEDURE start_worksheet(p_fh IN UTL_FILE.FILE_TYPE
, p_sheetname IN VARCHAR2);
PROCEDURE end_worksheet (p_fh IN UTL_FILE.FILE_TYPE);
PROCEDURE set_date_style (p_fh IN UTL_FILE.FILE_TYPE);
end tabletoexcel;
create or replace package body tabletoexcel
as
PROCEDURE run_query(p_fh UTL_FILE.FILE_TYPE
, p_sql IN VARCHAR2) IS
v_v_val VARCHAR2(4000);
v_n_val NUMBER;
v_d_val DATE;
v_ret NUMBER;
c NUMBER;
d NUMBER;
col_cnt INTEGER;
f BOOLEAN;
rec_tab DBMS_SQL.DESC_TAB;
col_num NUMBER;
BEGIN
c := DBMS_SQL.OPEN_CURSOR;
-- parse the SQL statement
DBMS_SQL.PARSE(c, p_sql, DBMS_SQL.NATIVE);
-- start execution of the SQL statement
d := DBMS_SQL.EXECUTE(c);
-- get a description of the returned columns
DBMS_SQL.DESCRIBE_COLUMNS(c, col_cnt, rec_tab);
-- bind variables to columns
FOR j in 1..col_cnt
LOOP
CASE rec_tab(j).col_type
WHEN 1 THEN DBMS_SQL.DEFINE_COLUMN(c,j,v_v_val,4000);
WHEN 2 THEN DBMS_SQL.DEFINE_COLUMN(c,j,v_n_val);
WHEN 12 THEN DBMS_SQL.DEFINE_COLUMN(c,j,v_d_val);
ELSE
DBMS_SQL.DEFINE_COLUMN(c,j,v_v_val,4000);
END CASE;
END LOOP;
-- Output the column headers
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Row>');
FOR j in 1..col_cnt
LOOP
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="String">'||rec_tab(j).col_name||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
END LOOP;
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Row>');
-- Output the data
LOOP
v_ret := DBMS_SQL.FETCH_ROWS(c);
EXIT WHEN v_ret = 0;
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Row>');
FOR j in 1..col_cnt
LOOP
CASE rec_tab(j).col_type
WHEN 1 THEN DBMS_SQL.COLUMN_VALUE(c,j,v_v_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="String">'||v_v_val||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
WHEN 2 THEN DBMS_SQL.COLUMN_VALUE(c,j,v_n_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="Number">'||to_char(v_n_val)||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
WHEN 12 THEN DBMS_SQL.COLUMN_VALUE(c,j,v_d_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell ss:StyleID="OracleDate">');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="DateTime">'||to_char(v_d_val,'YYYY-MM-DD"T"HH24:MI:SS')||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
ELSE
DBMS_SQL.COLUMN_VALUE(c,j,v_v_val);
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Cell>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Data ss:Type="String">'||v_v_val||'</ss:Data>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Cell>');
END CASE;
END LOOP;
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Row>');
END LOOP;
DBMS_SQL.CLOSE_CURSOR(c);
END run_query;
PROCEDURE start_workbook (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'<?xml version="1.0"?>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Workbook xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet">');
END start_workbook;
PROCEDURE end_workbook (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Workbook>');
END end_workbook;
--
PROCEDURE start_worksheet(p_fh UTL_FILE.FILE_TYPE
, p_sheetname IN VARCHAR2) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Worksheet ss:Name="'||p_sheetname||'">');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Table>');
END start_worksheet;
PROCEDURE end_worksheet (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Table>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Worksheet>');
END end_worksheet;
--
PROCEDURE set_date_style (p_fh UTL_FILE.FILE_TYPE) IS
BEGIN
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Styles>');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:Style ss:ID="OracleDate">');
UTL_FILE.PUT_LINE(gv_file_type,'<ss:NumberFormat ss:Format="dd/mm/yyyy\ hh:mm:ss"/>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Style>');
UTL_FILE.PUT_LINE(gv_file_type,'</ss:Styles>');
END set_date_style;
end tabletoexcel;
现在，我的匿名块最好像下面这样（请注意评论）：
declare
l_fh UTL_FILE.FILE_TYPE;
l_directory VARCHAR2(30) := 'EMPLOYEE_FILE_DIR';
l_filename VARCHAR2(30) := 'myfile.xls';
l_sql_statement VARCHAR2(4000);
Cursor emp_cur (p_emp_no varchar2
,p_payroll_id number
,p_bg_id number)
is
select *
from table_a
where employee_number = nvl(p_emp_no, employee_number)
and payroll_id = nvl(p_payroll_id, payroll_id);
and business_group_id = p_bg_id
-- This is the Really really long query but i just placed Table_A for Sample Purposes
BEGIN
l_fh := UTl_file.FOPEN(upper(l_directory),l_filename,'w',32767);
tabletoexcel.start_workbook (l_fh);
tabletoexcel.set_date_style (l_fh);
tabletoexcel.start_worksheet(l_fh, 'EMP');
tabletoexcel.run_query(emp_cur('1', 2, 3));
-- I'm sure this won't work, but i would like to pass something simple as this.
tabletoexcel.end_worksheet (l_fh);
tabletoexcel.end_workbook (l_fh);
UTl_file.FCLOSE(l_fh);
END;
是否可以将显式游标定义传递给 DBMS_SQL 包？
我在考虑 Returns 显式游标的 SQL 语句的内置函数可以解决这个问题。也许是参考光标？
是的，您可以使用 DBMS_SQL.TO_CURSOR_NUMBER 函数来做到这一点。您的程序将如下所示：
PROCEDURE run_query(p_cur IN OUT SYS_REFCURSOR) IS
...
BEGIN
c := DBMS_SQL.TO_CURSOR_NUMBER(p_cur);
-- get a description of the returned columns
DBMS_SQL.DESCRIBE_COLUMNS(c, col_cnt, rec_tab);
...
然后你必须这样称呼它：
declare
l_cur SYS_REFCURSOR;
BEGIN
OPEN l_cur FOR
select *
from table_a
where employee_number = nvl(p_emp_no, employee_number)
and payroll_id = nvl(p_payroll_id, payroll_id);
and business_group_id = p_bg_id
...;
tabletoexcel.run_query(l_cur);
OPEN FOR 语句允许 CLOB 作为语句，因此在大小方面没有实际限制。
由于您在设计时不知道将选择哪些列（至少我是这么认为的），因此无法摆脱 DBMS_SQL.DESCRIBE_COLUMNS 和 DBMS_SQL.DEFINE_COLUMN。否则你可以使用 FETCH Statement 而不是 DBMS_SQL.FETCH_ROWS(c)