This may be a case of my ignorance to what is meant by a dependency.
When I run the following query I get a slightly different list (more entries) to when I chose the menu option View Dependencies (first node level only) why would that be? I should add I am ignoring VIEW dependencies, for example I have a 2 foreign key relationships set up to 2 different tables (pretty much identical configuration) yet only 1 is shown in the View Dependencies yet both a seen in the following query.
I got this off some other post:
SELECT DISTINCT
pt.object_id PrimaryTableID, pt.name PrimaryTableName
FROM
REPDEV.sys.foreign_keys fk
JOIN
REPDEV.sys.tables ft ON fk.referenced_object_id = ft.object_id
JOIN
REPDEV.sys.tables pt ON fk.parent_object_id = pt.object_id
WHERE
ft.name = 'MyTable'
ORDER BY
2
Am I suppose to use other means to get table relationship dependencies?
Include full outer join instead of join (inner join) and add the clause
"fk.name is not null" in where.
Tell me if works :)
Related
Pseudocode:
Get all projects
Use a table function to get all related parts, which uses project id as input and returns 0..* part ids
Copy a value from project to all found part ids
Datamodel:
Table projects consists of fields pj_id and pj_desc
Table parts consists of fields pj_desc_copy and prt_id
There's a function LookupRelationShips(string) that outputs multiple columns (rel_type and rel_id, where if rel_type = 2, rel_id would be a prt_id
My best attempt is this, but it won't let me use the output of the subselect:
UPDATE parts
SET pj_desc_copy = rel.pj_desc
from parts prt
INNER JOIN
(select (select rel_type, rel_id, pj.pj_desc
from LookupRelationShips(pj.pj_id)
where rel_type = 2)
from projects pj) as rel
ON rel.rel_id = prt.prt_id
Use case/restrictions:
This is a one-time statement to update all current parts. From this point onwards project CRUD will result in syncing parts, but using the application to bulk update previous projects is less than ideal (built-in timeouts, lots of overhead, large dataset).
I think your query should be as follow. You can use CROSS APPLY() on the function
UPDATE prt
SET pj_desc_copy = rel.pj_desc
FROM parts prt
INNER JOIN projects pj ON pj.rel_id = prt.prt_id
CROSS APPLY LookupRelationShips(pj.pj_id) rel
WHERE rel.rel_type = 2
UPDATE parts
SET pj_desc_copy = pj.pj_desc
FROM projects pj
CROSS APPLY LookupRelationShips(pj.pj_id) rel
RIGHT JOIN parts prt on rel.rel_id = prt.prt_id
WHERE rel.rel_type = 2
I have a custom query along these lines. I get the list of orderIds from outside. I have the entire order object list with me, so I can change the query in any way, if needed.
#Query("SELECT p FROM Person p INNER JOIN p.orders o WHERE o.orderId in :orderIds)")
public List<Person> findByOrderIds(#Param("orderIds") List<String> orderIds);
This query works fine, but sometimes it may have anywhere between 50-1000 entries in the orderIds list sent from outside function. So it becomes very slow, taking as much as 5-6 seconds which is not fast enough. My question is, is there a better, faster way to do this? When I googled, and on this site, I see we can use ANY, EXISTS: Postgresql: alternative to WHERE IN respective WHERE NOT IN or create a temporary table: https://dba.stackexchange.com/questions/12607/ways-to-speed-up-in-queries-under-postgresql or join this to VALUES clause: Alternative when IN clause is inputed A LOT of values (postgreSQL). All these answers are tailored towards direct SQL calls, nothing based on JPA. ANY keyword is not supported by spring-data. Not sure about creating temporary tables in custom queries. I think I can do it with native queries, but have not tried it. I am using spring-data + OpenJPA + PostgresSQL.
Can you please suggest a solution or give pointers? I apologize if I missed anything.
thanks,
Alice
You can use WHERE EXISTS instead of IN Clause in a native SQL Query as well as in HQL in JPA which results in a lot of performance benefits. Please see sample below
Sample JPA Query:
SELECT emp FROM Employee emp JOIN emp.projects p where NOT EXISTS (SELECT project from Project project where p = project AND project.status <> 'Active')
I'm having trouble with the 'Ambiguous column name' issue in Transact-SQL, using the Microsoft SQL 2012 Server Management Studio.
I´ve been looking through some of the answers already posted on Stackoverflow, but they don´t seem to work for me, and parts of it I simply don´t understand or loses the general view of.
Executing the following script :
USE CDD
SELECT Artist, Album_title, track_title, track_number, Release_Year, EAN_code
FROM Artists AS a INNER JOIN CD_Albumtitles AS c
ON a.artist_id = c.artist_id
INNER JOIN Track_lists AS t
ON c.title_id = t.title_id
WHERE track_title = 'bohemian rhapsody'
triggers the following error message :
Msg 209, Level 16, State 1, Line 3
Ambiguous column name 'EAN_code'.
Not that this is a CD database with artists names, album titles and track lists. Both the tables 'CD_Albumtitles' and 'Track_lists' have a column, with identical EAN codes. The EAN code is an important internationel code used to uniquely identify CD albums, which is why I would like to keep using it.
You need to put the alias in front of all the columns in your select list and your where clause. You're getting that error because one of the columns you have currently is coming from multiple tables in your join. If you alias the columns, it will essentially pick one or the other of the tables.
SELECT a.Artist,c.Album_title,t.track_title,t.track_number,c.Release_Year,t.EAN_code
FROM Artists AS a INNER JOIN CD_Albumtitles AS c
ON a.artist_id = c.artist_id
INNER JOIN Track_lists AS t
ON c.title_id = t.title_id
WHERE t.track_title = 'bohemian rhapsody'
so choose one of the source tables, prefixing the field with the alias (or table name)
SELECT Artist,Album_title,track_title,track_number,Release_Year,
c.EAN_code -- or t.EAN_code, which should retrieve the same value
By the way, try to prefix all the fields (in the select, the join, the group by, etc.), it's easier for maintenance.
I have a relatively simple thing that I can do easily in SQL, but I'm trying to get used to using Lambda expressions, and having a hard time.
Here is a simple example. Basically I have 2 tables.
tblAction (ActionID, ActionName)
tblAudit (AuditID, ActionID, Deleted)
tblAudit may have an entry regarding tblAction with the Deleted flag set to 1.
All I want to do is select actions where we don't have a Deleted entry in tblAudit. So the SQL statement is:
Select tblAction.*
From tblAction LEFT JOIN tblAudit on tblAction.ActionID=tblAudit.ActionID
where tblAudit.Deleted <> 1
What would be the equivalent of the above in VB.Net's LINQ? I tried:
Context.Actions.Where(Function(act) Context.Audit
.Where(Function(aud) aud.Deleted=False AndAlso aud.ActionID=act.ActionID)).ToList
But that is really an inner join type scenario where it requires that each entry in tblAction also has an Entry in tblAudit. I am using Entity Framework Code First to do the database mapping. Is there a way to define the mapping in a way where you can do this?
You should add
Public Property Audits As DbSet<Audit>
into your action entity class (to register the association between those tables).
Now you can just write what you mean:
(From act in Context.Actions Where Not act.Audits.Any(Function(audit) audit.Deleted)).ToArray
which is equivalent to
Context.Actions.Where(Function(act) Not act.Audits.Any(Function(audit) audit.Deleted)).ToArray
and let the LINQ parser do the hard SQL work.
Example:
SELECT `cat`.`id_catalog`, COUNT(parent.id_catalog) - 1) AS `level` FROM `tbl_catalog` AS `cat`, `tbl_catalog` AS `parent` WHERE (cat.`left` BETWEEN parent.`left` AND parent.`right`) GROUP BY `cat`.`id_catalog` ORDER BY `cat`.`left` ASC
It doesn't seem to work if it use ZF. ZF create this query with join only. How to create the select without join in ZF_DB.
By the way may be I do smth wrong in this query. It is simple nested set DB with parent, left and right fields. Perhaps there are another way to use join to get deep for some node. Anyway it would be interesting to get answer for both way:)
Thanks in advance to all who looks it through:)