环境：HP-UX 11.x C++ (ProC & aCC 编译器) Oracle 10g)
我无法从我的 C++ 嵌入式 SQL 代码中执行以下命令
EXEC SQL SELECT MAX(ORA_ROWSCN) INTO :scn_timestamp
FROM table_name ;
我所做的更改是针对现有文件的。以下是显示编译器错误的自动构建脚本的摘录：
/data/tsd_oracle/hpux/10.2.0.2/bin/proc +z ireclen=200 ORECLEN=200 LRECLEN=208 code=cpp cpp_suffix=C lines=yes sqlcheck=semantics maxopencursors=10 parse=PARTIAL unsafe_null=yes mode=oracle dbms=V8 sys_include='(/opt/aCC,/opt/aCC/include/iostream,/opt/aCC/include/rw,/usr/include)' include=/data/tsd_oracle/hpux/10.2.0.2/precomp/public include=/usr/include include=/opt/aCC/include include=/opt/aCC/include/SC iname=FILENAME.PC;
Pro*C/C++: Release 10.2.0.2.0 - Production on Fri Feb 15 12:48:35 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
System default option values taken from: /data/tsd_oracle/hpux/10.2.0.2/precomp/admin/pcscfg.cfg
Error at line 81, column 5 in file FILENAME.PC
EXEC SQL SELECT MAX(ora_rowscn) INTO :scn_timestamp
....1
PLS-S-00201, identifier 'ORA_ROWSCN' must be declared
Error at line 81, column 5 in file FILENAME.PC
EXEC SQL SELECT MAX(ora_rowscn) INTO :scn_timestamp
....1
PLS-S-00000, SQL Statement ignored
Semantic error at line 81, column 5, file FILENAME.PC:
EXEC SQL SELECT MAX(ora_rowscn) INTO :scn_timestamp
....1
PCC-S-02346, PL/SQL found semantic errors
*** Error code 1
clearmake: Error: Build script failed for "FILENAME.C"
默认选项值文件/data/tsd_oracle/hpux/10.2.0.2/precomp/admin/pcscfg.cfg的内容如下
sys_include=(/data/tsd_oracle/hpux/10.2.0.2/precomp/public,/usr/include)
ltype=short
define=ORASTDARG
我也尝试过该命令的变体，例如
EXEC SQL SELECT MAX(A.ORA_ROWSCN) INTO :scn_timestamp
FROM table_name A;
为此我收到错误说 ORA_ROWSCN 列不存在。
我已验证此 sql 查询在 SQLPlus 控制台中有效。嵌入时为什么不起作用的任何特殊原因？
--------------------------解决方法---------- ---------
根据多米尼克的建议，我成功地使用以下方法检索了我想要的东西
EXEC SQL PREPARE timestamp_stmt FROM 'SELECT MAX(A.ora_rowscn) FROM table_name A';
EXEC SQL DECLARE timestamp_cur CURSOR FOR timestamp_stmt;
EXEC SQL OPEN timestamp_cur;
EXEC SQL FETCH timestamp_cur INTO :scn_timestamp;
EXEC SQL CLOSE timestamp_cur;
我对这种解决方法感到满意，但我仍然想知道为什么它不能以通常的方式工作。我之前也尝试过使用游标，并且出现相同的错误，指出“必须声明标识符'ORA_ROWSCN'”。
无论如何，谢谢多米尼克