The NULL, in fact, doesn’t represent any value at all—it represents the lack of a value. When you create a column for a table that must have a value, you specify it as NOT NULL, meaning that it cannot contain a NULL value. If you try to write a row to a database table that...
SELECT DBMS_METADATA.GET_DDL(U.OBJECT_TYPE, u.object_name)FROM USER_OBJECTS u where U.OBJECT_TYPE IN ('TABLE','INDEX','PROCEDURE');3.得到所有表空间的ddl语句 SET SERVEROUTPUT ON SET LINESIZE 1000 SET FEEDBACK OFF set long 999999---显示不完整 SET PAGESIZE 1000---分页 ---去除storage...
不过一般在异常断电强制open数据库的时候遇到，正常运行的环境很少见，其含义如下：Meaning: seq# mismatch while adding an undo record to an undo block. This is done by the application of redo. ---Argument Description: a. (ktubhseq): undo record seq# - this is the seq# of the block ...
CONNECT SYSTEM/system_password DB_NAME = database_name xxvii Convention UPPERCASE lowercase Meaning Example Uppercase typeface indicates elements supplied by the system. We show these terms in uppercase in order to distinguish them from terms you define. Unless terms appear in brackets, enter them...
DDEis invokedinprotectedmode.DDEcall is aborted.***2021-11-0307:59:06.308Exception[type:SIGSEGV,Address not mapped to object][ADDR:0x505E9323][PC:0x981FF3E,kgebse()+776][flags:0x2,count:2]Not recording anORA-7445(previous attmpet failed)ssexhd:crashing the process...Background_Core_Dum...
全编纂,意思是将整个字段进行加密,要使用全编纂,需要将function_type参数设为DBMS_REDACT.FULL,接下来我们举例探索全加密效果。 举例1:对字符型的加密 SQL> BEGIN DBMS_REDACT.ADD_POLICY( object_schema => 'U1', object_name => 'TAB1', column_name => 'ID', ...
大量使用 PL/SQL 存储过程可以改善性能并优化内存用量(当然也存在过分依赖DBMS的缺点)。PL/SQL 编译器经过重新编写,新的编译器包括代码生成器和全局代码优化器,能够改善大部分PL/SQL程序的性能,尤其是计算密集型 PL/SQL 程序,对于一个单纯的 PL/SQL 程序来说,其性能比 Oracle9i Database Release 2 超出大约 2 ...
viii Preface Conventions The following text conventions are used in this document: Convention boldface italic monospace Meaning Boldface type indicates graphical user interface elements associated with an action, or terms defined in text or the glossary. Italic type indicates book titles, emphasis, or ...
Reference a nonprogram element defined in the package specification. Notice that you never actually execute a package itself. The package is simply a “container” for the various code elements defined in the package. Let’s take a look at an example to make all this very clear. The DBMS_...
API write operations whose start offset or buffer size is not aligned to the internal chunk size of the LOB. Writes aligned to chunk boundaries are the most efficient write operations. The internal chunk size of a LOB is available through the LOB API (for example, DBMS_LOB.GETCHUNKSIZE())...