Three built table occupied rollback segment size

The first: create table s as select * the from dba_objects; – The second: create table s as select * from dba_objects where 1 = 0; insert / * + append * / into s select * from dba_objects; Third: create table s as select * from dba_objects where 1 = 0; insert into s […]

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MS SQL to create a table-valued function

This is an example of creating a table, I feel very classic, so come up with to share with you CREATE FUNCTION [dbo]. [SplitToTable] ( @ RowData nvarchar (2000), @ SplitOn nvarchar (5) ) RETURNS @ RtnValue table ( Id int identity (1,1) Data nvarchar (100) ) AS BEGIN declare @ Cnt int Set @ […]

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Oracle internal operations

When we introduce a SQL statement, Oracle will do with it? Oracle will be allocated for each user process to a server process: the service Process (actual distinction should be made ??between a dedicated server and shared server), when the service Process received sql statement submitted by the user process, the server process will SQL statement syntax and […]

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Oracle table space to learn

Table spatial learning Personally feel that table space relative to the database is critical, is generally divided into permanent (permanent table space), undo (undo tablespace), temporary (temporary table space), generally by the following SQL View table space type. select distinct t.contents from dba_tablespaces t; View the table space corresponding to the data files. select t.name, […]

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SQL multi-table join queries

inner join, full outer join, left join, right jion A combination of internally connected inner join two tables are met full outer whole company, the same combination of the two tables together in Table A, Table B data (null), the same table B A table does not display (null) Table A left join B table […]

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SQL Server && mysql paging sql statement summary

the sqlserver paging statement the number of select top display per page * from table where the primary key id not in (select top each page displayed skilled * current page number primary key id from table) mysql select * from table limit the current page number * the number of the number of displayed […]

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Sqlserver Store null values ??to the database

If, as stored in the database null value or null, then he stored in the database will be stored in what form, if you want to remove this value from the database, then his whole value will show in what form. On this question when I do a project, I like the database stored in “value, […]

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95% of people do not know is hidden phone functions can be life-saving

1, invisible backup battery Your phone is running low, in order to allow it to continue to use, press * 3370 # key, the phone will restart after the start, you will find that electricity consumption increased by 50%. This part of the hidden reserve capacity used you have to recharge, recharge time, invisible backup battery […]

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slowest performing query

In SQL 2005 You CAN USE Management views the running Queries to find SLOW A good script i found a while ago on the WILL help get you started; it lists DATA, with the slowest Performing first. SELECT creation_time , last_execution_time , total_physical_reads , total_logical_reads , total_logical_writes , execution_count , total_worker_time , total_elapsed_time , total_elapsed_time […]

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usage of access like!!

Access do a fuzzy query always can not find the data, but the SQL statement on access can query data. The SQL statement is this: Electric Division SELECT count (cash) FROM student WHERE banji = ‘5010 ‘and computer like’ * two * ‘and final = 1; Tangled really bad, and why! ! “*” Represents obviously match 0 or […]

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