Oracle PL/SQL学习笔记(1)
1 SQL*Plus环境
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show all 显示所有SQL*Plus的命令名字
list or l 显示缓冲区的内容
list 4 显示当前SQL命令的第4行，并把第4行作为当前行。
change or c 用新的内容替换原来在一行中第一次出现内容,例如:SQL>c/(...)/('analyst')/
input or i 增加一行或多行
append or a 在一行后追加内容
del 删除当前行 删除SQL缓冲区中的当前行
run 显示并运行SQL缓冲区中的命令
/ 运行SQL缓冲区中的命令
edit 把SQL缓冲区中的命令写到操作系统下的文本文件，
并调用操作系统提供的编辑器执行修改。
set linesize 80 设置行的大小为80个字符宽度
set pagesize 100 设置页的大小为100行
ttitle 'smaple ttitle' 设置页头标
btitle 'smaple btitle' 设置页脚标
spool /home/zxin10/myresult.log 设置sqlplus的输出到文件中
spool off(out) 停止输出文件
column column_name format a18 wrap heading ’smaple-column-title’
格式化列输出,每列宽度18个字符,超过18个自动换行,列标题换成'column-title'
CLEAR COLUMNS 将所有列的显示属性设为缺省值.
2 异常exception
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no_data_found
表示select没有查询到满足条件的数据行。
others
表示Oracle预定义错误范围之外的任何错误,Oracle用这个"others"捕捉所有 未知的错误。可以使用sqlcode函数,sqlerrm函数在错误处理模块中显示错误 代码和错误信息。而且,others处理必须是一个块的最后一个错误处理,否则, others处理的优先级比较高,权利比较大,它会捕捉所有错误,包括预定义的Oracle 错误和非预定义的Oracle错误。
too_many_rows
Oracle的隐式游标,一次只能检索一行数据,使用隐式游标时,异常处理机制如果检测 到游标返回的数据是多行数据,它就抛出too_many_rows类型的异常。
dup_val_on_index
在某个索引上,出现重复值。
value_error
在某个目标字段中,放入的数据长度或者数据范围,超出目标字段定义的长度或者范围 ,如,把'8613905180088'这个字符串插入userid字段中,而userid定义为varchar2(10), 就会出现这种异常。
Exception Raised when ...
ACCESS_INTO_NULL
Your program attempts to assign values to the attributes of an uninitialized
(atomically null) object.
CASE_NOT_FOUND
None of the choices in the WHEN clauses of a CASE statement is selected, and
there is no ELSE clause.
COLLECTION_IS_NULL
Your program attempts to apply collection methods other than EXISTS to an
uninitialized (atomically null) nested table or varray, or the program attempts
to assign values to the elements of an uninitialized nested table or varray.
CURSOR_ALREADY_OPEN
Your program attempts to open an already open cursor. A cursor must be closed
before it can be reopened. A cursor FOR loop automatically opens the cursor to
which it refers. So, your program cannot open that cursor inside the loop.
DUP_VAL_ON_INDEX
Your program attempts to store duplicate values in a database column that is
constrained by a unique index.
INVALID_CURSOR
Your program attempts an illegal cursor operation such as closing an unopened cursor.
INVALID_NUMBER
In a SQL statement, the conversion of a character string into a number fails
because the string does not represent a valid number. (In procedural statements,
VALUE_ERROR is raised.) This exception is also raised when the LIMIT-clause
expression in a bulk FETCH statement does not evaluate to a positive number.
LOGIN_DENIED
Your program attempts to log on to Oracle with an invalid username and/or password.
NO_DATA_FOUND
A SELECT INTO statement returns no rows, or your program references a deleted element
in a nested table or an uninitialized element in an index-by table. SQL aggregate
functions such as AVG and SUM always return a value or a null. So, a SELECT INTO
statement that calls an aggregate function never raises NO_DATA_FOUND. The FETCH
statement is expected to return no rows eventually, so when that happens, no
exception is raised.
NOT_LOGGED_ON
Your program issues a database call without being connected to Oracle.
PROGRAM_ERROR
PL/SQL has an internal problem.
ROWTYPE_MISMATCH
The host cursor variable and PL/SQL cursor variable involved in an assignment have
incompatible return types. For example, when an open host cursor variable is passed
to a stored subprogram, the return types of the actual and formal parameters must
be compatible.
SELF_IS_NULL
Your program attempts to call a MEMBER method on a null instance. That is, the
built-in parameter SELF (which is always the first parameter passed to a MEMBER
method) is null.
STORAGE_ERROR
PL/SQL runs out of memory or memory has been corrupted.
SUBs cript_BEYOND_COUNT
Your program references a nested table or varray element using an index number
larger than the number of elements in the collection.
SUBs cript_OUTSIDE_LIMIT
Your program references a nested table or varray element using an index number
(-1 for example) that is outside the legal range.
SYS_INVALID_ROWID
The conversion of a character string into a universal rowid fails because the
character string does not represent a valid rowid.
TIMEOUT_ON_RESOURCE
A time-out occurs while Oracle is waiting for a resource.
TOO_MANY_ROWS
A SELECT INTO statement returns more than one row.
VALUE_ERROR
An arithmetic, conversion, truncation, or size-constraint error occurs. For example,
when your program selects a column value into a character variable, if the value is
longer than the declared length of the variable, PL/SQL aborts the assignment and raises
VALUE_ERROR. In procedural statements, VALUE_ERROR is raised if the conversion of a
character string into a number fails. (In SQL statements, INVALID_NUMBER is raised.)
ZERO_DIVIDE
Your program attempts to divide a number by zero.
3 连接查询
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假设两个表s1cardinf,s1prefer
s1cardinf内容:
allindex
1
2
3
s1prefer内容:
allindex
2
3
4
select a.allindex,b.allindex
from s1cardinf a , s1prefer b
where a.allindex = b.allindex ;
结果:
allindex,allindex
2 2
3 3
select a.allindex,b.allindex
from s1cardinf a , s1prefer b
where a.allindex (+) = b.allindex ;
结果:
allindex,allindex
2 2
3 3
null 4
select a.allindex,b.allindex
from s1cardinf a , s1prefer b
where a.allindex = b.allindex (+) ;
结果:
allindex,allindex
1 null
2 2
3 3