DDL在PL/SQL中不被支持,这就 意味作在PL/SQL程序块中不能创建表或其他任何对象。较好的PL/SQL程序设计是在PL/SQL块中 使用象DBMS_SQL这样的内建包或执行EXECUTE IMMEDIATE命令建立动态SQL来执行DDL命令, 下面我们将讨论各种用于访问ORACLE数据库的DDL和TCL语句。 查询 SELECT语句用于从数据库中查询数据,当在PL/SQ...
SQL>setserveroutputonSQL>declare2l_numbernumber:=1;3begin4l_number :=1+1;5dbms_output.put_line('1 + 1 ='||to_char(l_number)||'!');6exception7whenothersthen8dbms_output.put_line('We encountered an exception!');9end;10/1+1=2! PL/SQL 过程已成功完成。 工作原理 我们的程序块中首...
WithinPL/SQL, you can manipulate the nested table by looping through its elements, using methods such asTRIMorEXTEND, and updating some or all of the elements. Afterward, you can store the updated table in the database again. You caninserttable rows containing nested tables,updaterows to repla...
Oracle Database uses two engines to run PL/SQL blocks and subprograms. The PL/SQL engine runs procedural statements, while the SQL engine runs SQL statements. During execution, every SQL statement causes a context switch between the two engines, resulting in performance overhead. -- Oracle 使用...
After running a couple more queries to examine the data I picked partition p3 for testing, and 284 as a suitable product_id (249 rows in that partition), and created an anonymous PL/SQL block to execute a query to select 100 of those rows (using a couple of queries to generate most ...
An activity property page appears for you to select the activity for this node. See: To Define Nodes in a Process. In the process window, you can display information about an activity by moving your mouse over the activity. The Label Name, Internal Name, Display Name, Comment and Performer...
There are various built-in PL/SQL packages as well as the ability to create Java and C database objects that allow for additional access to the underlying OS.If you are considering scripting for a task that requires a good deal of database access, scripting is probably not your best ...
Bulk SQLminimizes the performance overhead of the communication between PL/SQL and SQL. PL/SQL and SQL communicate as follows: To run a SELECT INTO or DML statement, the PL/SQL engine sends the query or DML statement to the SQL engine. The SQL engine runs the query or DML statement and...
There are various built-in PL/SQL packages as well as the ability to create Java and C database objects that allow for additional access to the underlying OS.If you are considering scripting for a task that requires a good deal of database access, scripting is probably not your best ...
SQL was initially defined over a period of years by IBM Research, but it was Oracle Corporation that first introduced it to the market in 1979. SQL was noteworthy at the time for being the only language needed for relational databases since you could use SQL: For queries (using a SELECT ...