参数如下:INITIAL Specify in bytes the size of the object's first extent. Oracle allocates space for this extent when you create the schema object. Use K or M to specify this size in kilobytes or megabytes. The default value is the size of 5 data blocks. The minimum value is the size of 2 data blocks for nonbitmapped segments or 3 data blocks for bitmapped segments, plus one data block for each free list group you specify. The maximum value depends on your operating system. Oracle rounds values up to the next multiple of the data block size for values less than 5 data blocks, and rounds up to the next multiple of 5 data blocks for values greater than 5 data blocks. Restriction: You cannot specify INITIAL in an ALTER statement. See Also: FREELIST GROUPS for information on freelist groups
NEXT Specify in bytes the size of the next extent to be allocated to the object. Use K or M to specify the size in kilobytes or megabytes. The default value is the size of 5 data blocks. The minimum value is the size of 1 data block. The maximum value depends on your operating system. Oracle rounds values up to the next multiple of the data block size for values less than 5 data blocks. For values greater than 5 data blocks, Oracle rounds up to a value that minimizes fragmentation, as described in . If you change the value of the NEXT parameter (that is, if you specify it in an ALTER statement), the next allocated extent will have the specified size, regardless of the size of the most recently allocated extent and the value of the PCTINCREASE parameter. See Also: Oracle8i Concepts for information on how Oracle minimizes fragmentation
PCTINCREASE Specify the percent by which the third and subsequent extents grow over the preceding extent. The default value is 50, meaning that each subsequent extent is 50% larger than the preceding extent. The minimum value is 0, meaning all extents after the first are the same size. The maximum value depends on your operating system. Oracle rounds the calculated size of each new extent to the nearest multiple of the data block size. If you change the value of the PCTINCREASE parameter (that is, if you specify it in an ALTER statement), Oracle calculates the size of the next extent using this new value and the size of the most recently allocated extent. --------------------------------------------------------------------------------Suggestion: If you wish to keep all extents the same size, you can prevent SMON from coalescing extents by setting the value of PCTINCREASE to 0. In general, Oracle Corporation recommends a setting of 0 as a way to minimize fragmentation and avoid the possibility of very large temporary segments during processing. --------------------------------------------------------------------------------
Restriction: You cannot specify PCTINCREASE for rollback segments. Rollback segments always have a PCTINCREASE value of 0. MINEXTENTS Specify the total number of extents to allocate when the object is created. This parameter enables you to allocate a large amount of space when you create an object, even if the space available is not contiguous. The default and minimum value is 1, meaning that Oracle allocates only the initial extent, except for rollback segments, for which the default and minimum value is 2. The maximum value depends on your operating system. If the MINEXTENTS value is greater than 1, then Oracle calculates the size of subsequent extents based on the values of the INITIAL, NEXT, and PCTINCREASE parameters. Restriction: You cannot specify MINEXTENTS in an ALTER statement. MAXEXTENTS Specify the total number of extents, including the first, that Oracle can allocate for the object. The minimum value is 1 (except for rollback segments, which always have a minimum value of 2). The default value depends on your data block size. UNLIMITED Specify UNLIMITED if you want extents to be allocated automatically as needed. Oracle Corporation recommends this setting as a way to minimize fragmentation. However, do not use this clause for rollback segments. Rogue transactions containing inserts, updates, or deletes that continue for a long time will continue to create new extents until a disk is full.
Caution: A rollback segment that you create without specifying the storage_clause has the same storage parameters as the tablespace that the rollback segment is created in. Thus, if you create the tablespace with MAXEXTENTS UNLIMITED, then the rollback segment will also have the same default.
动态SQL ORACLE自带的文档很全面 例子也很详细
我的是oracle8.1.7我在哪里可以找到帮助啊？
我觉得SQL Server 中的OnLine Book就是做的不错. 可在ORACLE中,如果,想查一个函数的用法就查不到!?
那谁能把这个sql语句解释一下：
CREATE TABLE CJYSGB2 (
JH VARCHAR2(20),
GCSK_ZZJM VARCHAR2(20),
GCSK_CDW VARCHAR2(20),
GCSK_SF VARCHAR2(20),
SGYJJ VARCHAR2(20),
ZRJM2 VARCHAR2(20),
BCSB2 VARCHAR2(20),
BCSB5 VARCHAR2(20),
BCMD2 VARCHAR2(20),
BCZZ VARCHAR2(20),
SCX5 VARCHAR2(20),
YXMD VARCHAR2(20),
JBQX VARCHAR2(20))
TABLESPACE USERS
PCTFREE 10 PCTUSED 40
INITRANS 1 MAXTRANS 255
STORAGE (
INITIAL 128K NEXT 128K PCTINCREASE 0
MINEXTENTS 1 MAXEXTENTS 4096 )
NOCACHE; ALTER TABLE CJYSGB2 ADD CONSTRAINT FK_CJYSGB2_RELATIONS_CJYSGB
FOREIGN KEY (JH)
REFERENCES ADMPROFESSIONAL.CJYSGB (JH) ;
他说的比较详细
:另一个用户ADMPROFESSIONAL的CJYSGB的JH字段.
哪里有比较全面的ORACLE帮助呀,我觉得ORACLE自带的帮助其它就是拉及!
INITIAL 128K NEXT 128K PCTINCREASE 0
MINEXTENTS 1 MAXEXTENTS 4096 )
NOCACHE;
这句怎么解释？
例子也很详细
只不过是英文的
Specify in bytes the size of the object's first extent. Oracle allocates space for this extent when you create the schema object. Use K or M to specify this size in kilobytes or megabytes. The default value is the size of 5 data blocks. The minimum value is the size of 2 data blocks for nonbitmapped segments or 3 data blocks for bitmapped segments, plus one data block for each free list group you specify. The maximum value depends on your operating system. Oracle rounds values up to the next multiple of the data block size for values less than 5 data blocks, and rounds up to the next multiple of 5 data blocks for values greater than 5 data blocks. Restriction: You cannot specify INITIAL in an ALTER statement. See Also: FREELIST GROUPS for information on freelist groups
NEXT
Specify in bytes the size of the next extent to be allocated to the object. Use K or M to specify the size in kilobytes or megabytes. The default value is the size of 5 data blocks. The minimum value is the size of 1 data block. The maximum value depends on your operating system. Oracle rounds values up to the next multiple of the data block size for values less than 5 data blocks. For values greater than 5 data blocks, Oracle rounds up to a value that minimizes fragmentation, as described in . If you change the value of the NEXT parameter (that is, if you specify it in an ALTER statement), the next allocated extent will have the specified size, regardless of the size of the most recently allocated extent and the value of the PCTINCREASE parameter. See Also: Oracle8i Concepts for information on how Oracle minimizes fragmentation
PCTINCREASE
Specify the percent by which the third and subsequent extents grow over the preceding extent. The default value is 50, meaning that each subsequent extent is 50% larger than the preceding extent. The minimum value is 0, meaning all extents after the first are the same size. The maximum value depends on your operating system. Oracle rounds the calculated size of each new extent to the nearest multiple of the data block size. If you change the value of the PCTINCREASE parameter (that is, if you specify it in an ALTER statement), Oracle calculates the size of the next extent using this new value and the size of the most recently allocated extent.
--------------------------------------------------------------------------------Suggestion: If you wish to keep all extents the same size, you can prevent SMON from coalescing extents by setting the value of PCTINCREASE to 0. In general, Oracle Corporation recommends a setting of 0 as a way to minimize fragmentation and avoid the possibility of very large temporary segments during processing. --------------------------------------------------------------------------------
Restriction: You cannot specify PCTINCREASE for rollback segments. Rollback segments always have a PCTINCREASE value of 0. MINEXTENTS
Specify the total number of extents to allocate when the object is created. This parameter enables you to allocate a large amount of space when you create an object, even if the space available is not contiguous. The default and minimum value is 1, meaning that Oracle allocates only the initial extent, except for rollback segments, for which the default and minimum value is 2. The maximum value depends on your operating system. If the MINEXTENTS value is greater than 1, then Oracle calculates the size of subsequent extents based on the values of the INITIAL, NEXT, and PCTINCREASE parameters. Restriction: You cannot specify MINEXTENTS in an ALTER statement. MAXEXTENTS
Specify the total number of extents, including the first, that Oracle can allocate for the object. The minimum value is 1 (except for rollback segments, which always have a minimum value of 2). The default value depends on your data block size. UNLIMITED
Specify UNLIMITED if you want extents to be allocated automatically as needed. Oracle Corporation recommends this setting as a way to minimize fragmentation. However, do not use this clause for rollback segments. Rogue transactions containing inserts, updates, or deletes that continue for a long time will continue to create new extents until a disk is full.
Caution: A rollback segment that you create without specifying the storage_clause has the same storage parameters as the tablespace that the rollback segment is created in. Thus, if you create the tablespace with MAXEXTENTS UNLIMITED, then the rollback segment will also have the same default.
ORACLE自带的文档很全面
例子也很详细
可在ORACLE中,如果,想查一个函数的用法就查不到!?
用oracle的搜索功能oracle中的函数
oracle8i/doc/server.815/a67779/function.htm
oracle的帮助和sql server的帮助比起来简直就等于什么都没有。