UPDATE, DELETE 操作时,它自动更新dept_summary 表中的数据。由于在PL/SQL块中不能直接调用DDL语句,所以,利用ORACLE内置包DBMS_UTILITY中的EXEC_DDL_STATEMENT过程由它执行DDL语句创建触发器。 CREATE TABLE deptsummary Deptno NUMBER(2),Sal_sum NUMBER(9, 2),
...编辑|SQL和数据库技术(ID:SQLplusDB) ORACLE: SQL> create table tab2(c1 number, c2 number, c3 varchar2(10)); 表が...---+---+---+---+---+ 1 row in set, 1 warning (0.00 sec) 结论: Oracle...的B-tree索引不存储Null,所以“c2 is null”条件的检索不能从索引中受益。...Mysq...
CASE语句语法: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 CASE variable_name WHEN case1 THEN statement1; WHEN case2 THEN statement2; ...WHEN caseN-1 THEN statementN-1; [ELSE statementN]END CASE; 实例如下: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 DECLARE grade CHAR :='B...
当sync_binlog =N (N>0) ，MySQL 在每写N次 二进制日志binary log时，会使用fdatasync()函数将它的写二进制日志binary log同步到磁盘中去。注：如果启用了autocommit，那么每一个语句statement就会有一次写操作；否则每个事务对应一个写操作。max_allowed_packet在导大容量数据特别是CLOB数据时，可能会出现异常：“...
2.输入:"sqlplus scott/tiger" 连接数据库 "show user":显示当前用户 conn 账户/口令:连接别的用户 select username,account_status from dba_users:查看用户状态 还可以指定用户名:select username,account_status from dba_users where username = 'SCOTT'; ...
statement1; [ELSIF condition2 THEN statement2;] …… [ELSE else_statement;] END IF; (2) CASE:表达式结果为true或false WHEN boolean_expression1 THEN statement1; WHEN boolean_expression2 THEN statement2; …… WHEN boolean_expressionN THEN statementN; ...
Runs an XQuery 1.0 statement. Supported SET commands SET APPI[NFO]{ON | OFF | text} Sets automatic registering of scripts through the DBMS_APPLICATION_INFO package. SET AUTO[COMMIT]{ON | OFF | IMM[EDIATE] | n} Controls when Oracle Database commits pending changes to the database. ...
The default value can be changed using the SET_PARAM Procedure NULL means use the table default value specified by the DEGREE clause in the CREATE TABLE or ALTER TABLE statement. Use the constant DBMS_STATS.DEFAULT_DEGREE to specify the default value based on the initialization parameters. The ...
sqlplusc##xstrmadmin/password@host:port/SID Among them: c##xstrmadminindicates the username of the XStream administrator, which is created in2.b. passwordindicates the password of the XStream administrator, which is configured in2.b. hostindicates the IP address of the server where the database...
oracle@dm09dbadm01:/home/oracle$ echo $ORACLE_HOME /u01/app/oracle/product/19.7.0.0/db oracle@dm09dbadm01:/home/oracle$ sqlplus -V SQL*Plus: Release 19.0.0.0.0 - Production Version 19.7.0.0.0 grid@dm09dbadm01:/home/grid$ asmcmd lsdg State Type Rebal Sector Logical_Sector Block AU To...