|
Index2 is the faster one because index1 will not be used at all except maybe for a full scan.
You might want to create it as;
create index index2 on Table (id0, id1, id2 DESC) But the difference is academical at best. SQL Server can scan in reverse direction after all.
|
|
|
|
|
For that query, definitely index 2.
Think of it like searching a massive address book. You're trying to find the highest house number for anyone called "John Smith".
- Index 1 sorts the addresses by house number, and includes the first and last name. You have to start at the end and scan backwards until you find an entry for "John Smith".
- Index 2 sorts the addresses by first name, then last name, then house number. You can jump straight to the end of the "John Smith" records, and see the highest house number.
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
|
|
|
|
|
The quote below is from An Introduction to Database Systems, 8th edition, C J Date.
Is that possible systems crash while transferring updates from the physical device to the database?
If yes, since transactions are the unit of recovery, those updates that are written to the database should be undone?
"It is quite possible, for instance, that the system might crash after the COMMIT has been honored but before the updates have been physically written to the database--they might still be waiting in a main-memory buffer and so lost at the time of the crash. Even if that happens, the system's restart procedure will still record those updates in the database: it is able to discover the values to be written by examining the relevant records in the log."
modified 2-Feb-20 13:48pm.
|
|
|
|
|
Not sure if I understand the question correctly, but are you looking for Rollforward? . With rollforward, when the database is recovered, all the logs are reapplied and in the end, everything that is not committed is rolled back. This guarantees a consisted situation even after crash.
If the recovery is interrupted because of a new crash, the recovery is simply started from the beginning next time.
|
|
|
|
|
Many thanks!
Sorry can you please explain this:
If the system crash after the COMMIT has been honored but just part of the updates have been physically written to the database other parts are still waiting in a main-memory buffer, then what will happen? How they know that just part of the data is written?
|
|
|
|
|
It's explained in the text you quoted:
"... the system's restart procedure will still record those updates in the database: it is able to discover the values to be written by examining the relevant records in the log."
|
|
|
|
|
The quote below is from *An Introduction to Database Systems, 8th edition, C J Date*.
Is that possible systems crash while transferring the updates from physical device to database?
"It is quite possible, for instance, that the system might crash after the COMMIT has been honored but before the updates have been physically written to the database--they might still be waiting in a main-memory buffer and so lost at the time of the crash. Even if that happens, the system's restart procedure will still record those updates in the database: it is able to discover the values to be written by examining the relevant records in the log."
modified 2-Feb-20 13:48pm.
|
|
|
|
|
In theory, yes. I would expect modern databases to wait for verification of the write before returning from the commit, which implies reading to verify after the data has been written.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
|
|
|
|
|
I want to copy the structure of all the tables of one database from one server to another server by using Stored Procedure ( due to automation ) there should be no index, no trigger , no fkr etc
|
|
|
|
|
Nice requirement. You have permission to proceed 
"Five fruits and vegetables a day? What a joke!
Personally, after the third watermelon, I'm full."
|
|
|
|
|
Easiest way to copy the structure is to do a backup, initiated from the sproc. You can restore that on whatever server you want.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
|
|
|
|
|
For example to transfer the sum of $100 from account 123 to account 456. we want the total number of dollars in accounts 123 and 456 taken together not to change.
Why it would be unreasonable to declare an integrity constraint to that effect?
|
|
|
|
|
That is what transactions are for, wrap the transfer in a transaction if there is an error roll back the transaction. An after process integrity check is not unreasonable but the correct way is with a transaction.
Never underestimate the power of human stupidity -
RAH
I'm old. I know stuff - JSOP
|
|
|
|
|
But the book says it's unreasonable.
|
|
|
|
|
The book should say it is incorrect or redundant and should recommend using a transaction. All books are not 100% correct all the time.
Never underestimate the power of human stupidity -
RAH
I'm old. I know stuff - JSOP
|
|
|
|
|
Tara11 wrote: Why it would be unreasonable to declare an integrity constraint to that effect?
Mainly because integrity constraint operate on row-basis. Transactions then again ensure that the operation is completed as a whole even when multiple commands are affected.
But neither of these guarantee that the total sum is unaffected when money is transferred. If this would be a single table operation, a trigger could be utilized to do that check.
modified 2-Feb-20 15:32pm.
|
|
|
|
|
Hi
I have to migrate a database from Oracle to MS-SQL. The database migration went well, but i have a query that gives me trouble. I have tried to convert it using this on-line tool - http://www.sqlines.com/online, but it is not working since the Oracle alias seems to be a problem for MS-SQL.
Is there any way to use a similar syntax in MS-SQL?
The original Oracle SQL:
UPDATE folk.individ c
SET (c.stat,
c.statusdto,
c.pnrgaeld,
c.koen,
c.fornvnmrk,
c.mellemnvnmrk,
c.efternvnmrk,
c.nvndto,
c.fornvn_solo,
c.fornvn,
c.mellemnvn,
c.efternvn,
c.adr_fornvn,
c.adr_efternvn,
stilling,
z_stilling,
c.z_fornvn,
c.z_mellemnvn,
c.z_efternvn,
c.z_adr_fornvn,
c.z_adr_efternvn,
c.z_fornvn_solo,
c.haenstart_umrk_navne,
c.stillingdto,
c.mynkod_ctnavn,
c.myntxt_ctnavn,
c.indrap,
c.adrnvndto,
c.soegnvn,
c.soegnvndto
) =
(SELECT l.status,
TO_DATE(DECODE(SUBSTR(l.statushaenstart,7,2),'00',NULL,
SUBSTR(l.statushaenstart,1,8)),'YYYYMMDD'),
l.pnrgaeld,
l.koen,
a.fornvn_mrk,
a.melnvn_mrk,
a.efternvn_mrk,
TO_DATE(DECODE(SUBSTR(a.nvnhaenstart,7,2),'00',NULL,
SUBSTR(a.nvnhaenstart,1,8)),'YYYYMMDD'),
Upper(a.fornvn), -- c.fornvn_solo
substr(decode(a.melnvn, null, upper(a.fornvn), upper(a.fornvn)|| ' ' || upper(a.melnvn) ),1,50), -- skal være som før: fornavn indh. også mlnavne
upper(a.melnvn),
upper(a.efternvn),
upper(LTRIM(SUBSTR(a.adrnvn, INSTR(a.adrnvn,',')+1))), --adr_fornvn
upper(SUBSTR(a.adrnvn,1,INSTR(a.adrnvn,',') - 1)), --adr_efternavn
upper(l.stilling),
l.stilling,
substr(decode(a.melnvn, null, a.fornvn, a.fornvn || ' ' || a.melnvn),1,50), -- z_fornvn, fornavn indh. også mlnavne
a.melnvn, -- z_mellemnvn
a.efternvn,
LTRIM(SUBSTR(a.adrnvn, INSTR(a.adrnvn,',')+1)), --z_adr_fornvn
SUBSTR(a.adrnvn,1,INSTR(a.adrnvn,',') - 1), -- z_adr_eftermnvn
a.fornvn, -- z_fornvn_solo
a.haenstart_umrk_navne, -- anvendelse ukendt
null, --stillingdto udgået
null, --mynkod_ctnavn udgået
null, --myntxt_ctnavn udgået
null, --indrap udgået
null, -- adrnvndto udgået
null, --soegnvn udgået
null --soegnvndto udgået
FROM folk.lperson2010 l, folk.laktnvnopl2010 a
WHERE l.pnr = c.pnr
AND l.pnr = a.pnr
AND l.lseq BETWEEN 1 AND 6000 )
where c.pnr in (select l.pnr FROM folk.lperson2010 l
where l.lseq BETWEEN 1 AND 6000 );
The code after conversion parsing it through http://www.sqlines.com/online:
UPDATE folk.individ c
SET (c.stat,
c.statusdto,
c.pnrgaeld,
c.koen,
c.fornvnmrk,
c.mellemnvnmrk,
c.efternvnmrk,
c.nvndto,
c.fornvn_solo,
c.fornvn,
c.mellemnvn,
c.efternvn,
c.adr_fornvn,
c.adr_efternvn,
stilling,
z_stilling,
c.z_fornvn,
c.z_mellemnvn,
c.z_efternvn,
c.z_adr_fornvn,
c.z_adr_efternvn,
c.z_fornvn_solo,
c.haenstart_umrk_navne,
c.stillingdto,
c.mynkod_ctnavn,
c.myntxt_ctnavn,
c.indrap,
c.adrnvndto,
c.soegnvn,
c.soegnvndto
) =
(SELECT l.status,
CONVERT(DATETIME, CASE SUBSTRING(l.statushaenstart,7,2) WHEN '00' THEN NULL
ELSE SUBSTRING(l.statushaenstart,1,8) END,'YYYYMMDD'),
l.pnrgaeld,
l.koen,
a.fornvn_mrk,
a.melnvn_mrk,
a.efternvn_mrk,
CONVERT(DATETIME, CASE SUBSTRING(a.nvnhaenstart,7,2) WHEN '00' THEN NULL
ELSE SUBSTRING(a.nvnhaenstart,1,8) END,'YYYYMMDD'),
Upper(a.fornvn), -- c.fornvn_solo
substring(case when a.melnvn is null then upper(a.fornvn) isnull( else upper(a.fornvn), '')+ ' ' + isnull(upper(a.melnvn), '') end,1,50), -- skal være som før: fornavn indh. også mlnavne
upper(a.melnvn),
upper(a.efternvn),
upper(LTRIM(SUBSTRING(a.adrnvn, CHARINDEX(',', a.adrnvn)+1, LEN(a.adrnvn)))), --adr_fornvn
upper(SUBSTRING(a.adrnvn,1,CHARINDEX(',', a.adrnvn) - 1)), --adr_efternavn
upper(l.stilling),
l.stilling,
substring(case when a.melnvn is null then a.fornvn isnull( else a.fornvn, '') + ' ' + isnull(a.melnvn, '') end,1,50), -- z_fornvn, fornavn indh. også mlnavne
a.melnvn, -- z_mellemnvn
a.efternvn,
LTRIM(SUBSTRING(a.adrnvn, CHARINDEX(',', a.adrnvn)+1, LEN(a.adrnvn))), --z_adr_fornvn
SUBSTRING(a.adrnvn,1,CHARINDEX(',', a.adrnvn) - 1), -- z_adr_eftermnvn
a.fornvn, -- z_fornvn_solo
a.haenstart_umrk_navne, -- anvendelse ukendt
null, --stillingdto udgået
null, --mynkod_ctnavn udgået
null, --myntxt_ctnavn udgået
null, --indrap udgået
null, -- adrnvndto udgået
null, --soegnvn udgået
null --soegnvndto udgået
FROM folk.lperson2010 l, folk.laktnvnopl2010 a
WHERE l.pnr = c.pnr
AND l.pnr = a.pnr
AND l.lseq BETWEEN 1 AND 6000 )
where c.pnr in (select l.pnr FROM folk.lperson2010 l
where l.lseq BETWEEN 1 AND 6000 );
|
|
|
|
|
 
At a guess, you're looking for something like:
UPDATE
c
SET
stat = l.status,
statusdto = CASE SUBSTRING(l.statushaenstart, 7, 2)
WHEN '00' THEN NULL
ELSE CONVERT(datetime, SUBSTRING(l.statushaenstart, 1, 8))
END,
pnrgaeld = l.pnrgaeld,
koen = l.koen,
fornvnmrk = a.fornvn_mrk,
mellemnvnmrk = a.melnvn_mrk,
efternvnmrk = a.efternvn_mrk,
nvndto = CASE SUBSTRING(a.nvnhaenstart, 7, 2)
WHEN '00' THEN NULL
ELSE CONVERT(datetime, SUBSTRING(a.nvnhaenstart, 1, 8))
END,
fornvn_solo = UPPER(a.fornvn),
fornvn = SUBSTRING(CASE
WHEN a.melnvn Is Null THEN UPPER(a.fornvn)
ELSE UPPER(a.fornvn) + ' ' + UPPER(a.melnvn)
END, 1, 50),
mellemnvn = UPPER(a.melnvn),
efternvn = UPPER(a.efternvn),
adr_fornvn = UPPER(LTRIM(SUBSTRING(a.adrnvn, CHARINDEX(',', a.adrnvn) + 1, LEN(a.adrnvn)))),
adr_efternvn = UPPER(SUBSTRING(a.adrnvn, 1, CHARINDEX(',', a.adrnvn) - 1)),
stilling = UPPER(l.stilling),
z_stilling = l.stilling,
z_fornvn = SUBSTRING(CASE
WHEN a.melnvn Is Null THEN a.fornvn
ELSE a.fornvn + ' ' + a.melnvn
END, 1, 50),
z_mellemnvn = a.melnvn,
z_efternvn = a.efternvn,
z_adr_fornvn = LTRIM(SUBSTRING(a.adrnvn, CHARINDEX(',', a.adrnvn) + 1, LEN(a.adrnvn))),
z_adr_efternvn = SUBSTRING(a.adrnvn, 1, CHARINDEX(',', a.adrnvn) - 1),
z_fornvn_solo = a.fornvn,
haenstart_umrk_navne = a.haenstart_umrk_navne,
stillingdto = Null,
mynkod_ctnavn = Null,
myntxt_ctnavn = Null,
indrap = Null,
adrnvndto = Null,
soegnvn = Null,
soegnvndto = Null
FROM
folk.individ As c
INNER JOIN folk.lperson2010 As l ON l.pnr = c.pnr
INNER JOIN folk.laktnvnopl2010 a ON a.pnr = c.pnr
WHERE
l.lseq BETWEEN 1 AND 6000
;
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
|
|
|
|
|
Thanks a lot. I did not realize that Oracle SQL and MS-SQL is that different from each other
|
|
|
|
|
|
I have a Schema in mongodb like:-
{
_id: ObjectId("5e05c1089b3e4e333cee8c39"),
name:"Alex",
activity:[{
{
_id: ObjectId("5e05c1089b3e4e333cee8c39"),
type: 'run',
start_timestamp: ISODate("2020-01-11T11:34:59.804Z"),
end_timestamp: ISODate("2020-01-11T11:40:00.804Z")
},
{
_id: ObjectId("5e05c1089b3e4e333cee8c40"),
type: 'stop',
start_timestamp: ISODate("2020-01-11T11:40:00.804Z"),
end_timestamp: ISODate("2020-01-11T11:42:00.804Z")
},
{
_id: ObjectId("5e05c1089b3e4e333cee8c41"),
type: 'wait',
start_timestamp: ISODate("2020-01-11T11:42:00.804Z"),
end_timestamp: ISODate("2020-01-11T11:52:00.804Z")
},
}]
}
This is a schema for a man activity, i need to find brake-up of every 15 minute (brake-up duration in minute) like
{
_id: "2020-01-11T11:34 to 2020-01-11T11:49" ,
duration: 15,
brake-up:{
run:6,
stop:2,
wait:7
}
}
here type: wait should be split into 2 duration "2020-01-11T11:34 to 2020-01-11T11:49" 7 min and "2020-01-11T11:49 to 2020-01-11T12:04" 3 min .
{
_id: "2020-01-11T11:34 to 2020-01-11T12:04" ,
duration: 15,
brake-up:{
wait:3
}
},
Thanks
modified 11-Jan-20 4:10am.
|
|
|
|
|
I am trying to set up a SQL query and I have a select statement that I need to setup a loop in it. It looks like this:
select jods.Company
, case when jos.SetupComplete = 0
then
-- Here is where I need to loop through the rows to get a calculation totaled up with the below equation
(((jods.SetupLabRate * jods.CrewSize) * jos.EstSetHours) * (1 - (jos.SetupPctComplete/100)))
else 0
end as SetupLabCost
any thoughts on this?
|
|
|
|
|
You have to show us the entire query. It appears as if you've setup a join, but we can't see it.
Typically, if you need a loop in a join, it's implemented as a sub-query, something like this:
select...
from mytable as a
join (select col1, col2, col3 from mytable) AS b on b.col = a.col
...
I can't be more specific based on your original question.
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
|
|
|
|
|
I also tried something like this and still not working:
, case when jos.SetupComplete = 0
then
--for ($i=0; $i<$count_row;$i++)
--{
-- (((jods.SetupLabRate * jods.CrewSize) * jos.EstSetHours) * (1 - (jos.SetupPctComplete/100)))
--}
else 0
end as SetupLabCost2
|
|
|
|
|
Again, without the associated table/view schemas, along with the entire query, we can't really help you, short of speculating as to what *might* be the proper approach.
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
