EF6 Code First: Many to Many Self referencing relationship
Hi,
Could any one show me an example for many to many self referencing?
The scenario is that I have a user table that will contains collection of users as friends.
Thanks,
Bo
Hi Kalman,
Really appreciate your answer.
I just wonder if I can, alternatively, set up tables as below,
Public class user
public int userId{get; set;}
public
virtual
ICollection<User> CircleOneFriends { get; set; }
public virtual ICollection<User>
CircleTwoFriends { get; set; }
public User()
CircleOneFriends
= new HashSet<User>();
CircleTwoFriends = new HashSet<User>();
public class UserConfiguration : EntityTypeConfiguration<User>
public
UserConfiguration()
this.HasMany(x=>x.CircleOneFriends) .WithMany(x=>x.CircleTwoFriends).Map(x=>x.ToTable("Friends"))
Do you think that will work in my case?
Thanks a lot,
Bo
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Self-referencing relationship line is non-movable
I am using Version 3.0.0.665 of data modeler. When I create a self-referencing relationship, the relationship line ends cannot be moved. They seem to be fixed. Is this the normal behavior. Any way to make them more flexible.
You can't adjust the size of self referencing lines at the stage. We do have this logged to fix in a future release.
Sue -
EF6 Code first inheritance from relationship
I need to create a TPH inheritance on an existing database using EF6 and Code first
Table Person
PersonId (Key)
PersonName
PersonTypeId (FK)
Table PersonType:
PersonTypeId (Key)
Description
Category
The field PersonTypeId is the discriminator for the employees and managers, and the classes that I use are:
class Person
public string PersonId {get; set;}
public string TypeId {get; set;}
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I use the fluent API to create the relationship between Person and
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Any suggestions??I try to explain me better
m.Requires("PersonTypeId").HasValue("EMP")
It's ok, but it's not what I need
The mapping discriminator is not the PersonTypeId but the Category field that is in the class(or table) referred by PersonTypeId
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If I choose your solution I need that PersonTypeId has more than one value
Like that:
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I try to explain me better
m.Requires("PersonTypeId").HasValue("EMP")
It's ok, but it's not what I need
The mapping discriminator is not the PersonTypeId but the Category field that is in the class(or table) referred by PersonTypeId
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If I choose your solution I need that PersonTypeId has more than one value
Like that:
m.Requires("PersonTypeId").HasValue("1").HasValue("2");
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Self referencing table many to many relationship
I am in a bit of a logic pickle, and I was wondering if someone could help me out.
I have a table in a database I am designing called document, it holds information on surprisingly on documents in our DMS.
I want to create the notion that a document can have multiple related documents, and those documents can be the related documents for many documents.
So it is a self referencing table, I have done these before so no big deal, but this time is a many to many relation, it wasnt before.
Maybe something like:
document
docid (pk)
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Does anyone have any experience with this or any advise I might find sueful?
Thanks!A junction table can be used to resolve a many-to-many relationship as is in your example. There are two PK/FK relationships between document and related_document table. This will prevent denormalization of data.
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But I think the approach you have in your posting will work well.
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http://www.impact-sol.com
Developers of Guggi Oracle - Tool for DBAs and Developers -
What are unicode code points and how many are there and which are surrogate
what are unicode code points and how many are there and which are surrogate
Hi
see the links
The Link will be helpful to you.
Re: Upgrade 4.6 to ECC - What are the responsibilites
regarding Unicode influence in Standard programs
Very good document:
http://www.doag.org/pub/docs/sig/sap/2004-03/Buhlinger_Maxi_Version.pdf
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/d37d1ad9-0b01-0010-ed9f-bc3222312dd8
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/589d18d9-0b01-0010-ac8a-8a22852061a2
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/f8e316d9-0b01-0010-8e95-829a58c1511a
Reward points for useful Answers
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ITunes 11 downloaded album art disappeared from first song of many albums
In iTunes 11. the downloaded album artwork disappeared from the first song of many of my albums.
This just randomly happened; it wasn't after an upgrade or any other noticeable event.
The artwork is still associated with all the subsequent songs of the album, just not with the first one.
I do not want to embed the artwork into the music files.
Nor do I want to "Clear Downloaded Artwork" and redo "Get Album Artwork" for the affected albums, since some of the albums are no longer in the iTunes Store, so I won't be able to download their artwork anymore.
The best that I can think of is to:
1) remove the song that is missing the artwork from itunes without deleting the file from the hard drive
2) in iTunes, copy another song from the same album
3) delete the newly copied song from the hard drive without removing it from iTunes
4) in iTunes, "Get Info" on the newly copied song, which will tell me that it can't be found, and give me the option to "Locate" the file
5) "locate" the file by selecting from the hard drive the file for the song that was mising its artwork, and that was removed from iTunes in step 1
Unfortunately, this will remove the song's rating, play counts, etc., remove it from any playlists, and change the date added, etc.
Does anyone have a better solution?
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One company code can have how many charts of depepreciation?
HI EXPERTS,
ONE COMPANY CODE CAN HAVE HOW MANY CHARTS OF DEPRECIATION?
AND ONE CHART OF DEPRECIATION CAN HAVE HOW MANY DEPRECIATION AREAS?
THANKS IN ADVANCE.
Edited by: jmml_narayana on Dec 15, 2011 7:50 AMthanks srinivasa
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Self referencing table and SQL statement
In my database, I have a self-referencing table, the table itself is for projects, and it allows users to get a hierarchical view of the company.
Here is the SQL (modifier is the term we use for project code, BBCI is the top project)
SELECT
modifier, modifierDescription, level
FROM
modifier
WHERE
level <= 2
CONNECT BY PRIOR
modifier = parentModifier
START WITH modifier = 'BBCI'
ORDER BY level
That perticular query gets the first two levels in the structure. I use this information to produce a tree structure in a web app.
But users have requested it would be good if in the tree structure is showed an + or - depending on whether there were anymore children under each parent, or better still the number of children under it, for example
BBCI
+ BBCI_CHILD
+ BBCI_CHILD2
- BBCI_CHILD3
or
BBCI
+ BBCI_CHILD (3 projects underneath)
+ BBCI_CHILD2 (2 projects underneath)
- BBCI_CHILD3 (0 projects underneath)
I am really stumped on this issue, and I am sure there is a way to do this in the web app, so for example do a query for each child node to see how many child nodes are underneath, but I figure it would be a lot tidier and faster if I could do it from a single SQL statement. Unfortunately I have tried to do this and am very much stuck.
If you need more information please let me know
Thanks!
JonYou may be able to do this using analytical functions but it depends on the Oracle version you are using. It can also be done with standard SQL - you just need to count the number of child rows for each modifier/project first and supply that list as an in-line view:
SELECT decode(modifier,'X',null,decode(child_rows,null,'-','+')),
m.modifier,
decode(modifier,'X',null,'('||nvl(cq.child_rows,0)||' projects underneath)')
FROM modifier m,
(select parentModifier,
count(parentModifier) child_rows
from modifier
where parentModifier is not null
group by parentModifier) cq
WHERE m.modifier=cq.parentModifier(+)
AND level <= 2
CONNECT BY PRIOR
m.modifier = m.parentModifier
START WITH modifier = 'X'
ORDER BY level, modifier;
which gives you something like...
D MODIFIER DECODE(MODIFIER,'X',NULL
X
- Y1 (0 projects underneath)
+ Y2 (2 projects underneath)
+ Y3 (3 projects underneath)
The decode stuff is just to show you the result, you can format the output in your calling code. Just extend the columns to include everything you want, modifierDescription etc..
Hope this helps. -
Plea for example - Many-to-Many CMP EJB
I am attempting to create an EJB that uses Container Managed Persistence,
but my situation seems to be an odd one. The EJB needs to have a
Many-to-Many relationship to itself, because the object is Hierarchical.
Because this is my first EJB I am having a hard time with all of the
deployment descriptors.
I am asking for an example of any Many-to-Many EJB relationship that uses
Weblogic's built-in link table creation to make the relationship (that
works). I realize that there are confidentiality issues with many people
releasing code. I will make any promise (short of selling my soul) that the
code will be safe and promply destroyed immediately after inspection.
Thanks for any help,
Tom
[email protected]The following describes how to establish a self many-to-many relationship with regards to Product having many parent products and many children products. I have attached the example files as well. Most of these files were generated using EJBGen. I would highly recommend it...
EJB
v Navigating from a Product to its parent Products results in getParents() method in Product
§ Since a Product can have many parents the return type of getParents() method is
java.util.Collection
§ Calling setParents() method results in establishing the new links between this Parent and
parent Products
§ Adding a Product as Parent to the Product results in establishing a new link between this
Product and other Product as parent
· This product is made available in the collection of children in the other Product
§ Removing a Product as Parent to the Product results in breaking a link between this
Product and the other Product as parent
· This product is also removed from the collection of children in the other Product
v Navigating from a Product to its children Products results in getChildren() method in Product
§ Since a Product can have many children the return type of getChildren() method is
java.util.Collection
§ Calling setChildren() method results in breaking the old links between this Product and
children Products
§ Adding a Product as child to the Product results in establishing a new link between this
Product and other Product as child
· This product is made available in the collection of parents in the other Product
§ Removing a Product as child from the Product results in breaking a link between this
Product and the other Product as child
· This Product is also removed from the collection of parents in the other Product.
v Example: ProductBean
Ø DataBase
v For a many-to-many relationship define a new associative (join) table
v Define a new Parent_Child_Product associative table
v The Parent_Child_Product has compound primary keys: Parent_Product_ID and
Child_Product_ID
v Parent_Product_ID and Child_Product_ID are foreign keys to Product table
v Example: Product, Parent_Child_Product
Ø Deployment Descriptors
v ejb-jar.xml
§ Within <ejb-jar>.<relationships>.<ejb-relation> define the following:
· Name of the relationship
o Example: <ejb-relation-name>Parent-Product-Children</ejb-relation-name>
· Role from the parent Product side
o Source
§ Example:
<relationship-role-source>
<ejb-name>Product</ejb-name>
</relationship-role-source>
o Role name
§ Example: <ejb-relationship-role-name>many-Product@children-Have-Product</
ejb-relationship-role-name>
o Multiplicity
§ Example: <multiplicity>many</multiplicity>
o CMR field
§ Example:
<cmr-field>
<cmr-field-name>children</cmr-field-name>
<cmr-field-type>java.util.Collection</cmr-field-type>
</cmr-field>
· Role from the child Product side
o Source
§ Example:
<relationship-role-source>
<ejb-name>Product</ejb-name>
</relationship-role-source>
o Role name
§ Example: <ejb-relationship-role-name>many-Product@parents-Have-Product</
ejb-relationship-role-name>
o Multiplicity
§ Example: <multiplicity>many</multiplicity>
o CMR field
§ Example:
<cmr-field>
<cmr-field-name>parents</cmr-field-name>
<cmr-field-type>java.util.Collection</cmr-field-type>
</cmr-field>
v weblogic-ejb-jar.xml
v weblogic-cmp-rdbms-jar.xml
§ Within <weblogic-rdbms-jar>.<weblogic-rdbms-relation> specify the following:.23
· Name of the relationship matching the name in ejb-jar
o Example: <ejb-relation-name> Parent-Product-Children</ejb-relation-name>
· Specify the name of the joint table
o Example: <table-name> Parent_Child_Product</table-name>
· Specify the mapping using <weblogic-relationship-role>
o Specify the role name matching the name in the ejb-jar
§ Example: <relationship-role-name>many-Product@children-Have-Product</
relationship-role-name>
o Define <relationship-role-map> that defines the mapping of the foreign key to
the primary key mapping
§ Example:
<relationship-role-map>
<column-map>
<foreign-key-column>Parent_Product_ID</foreign-key-column>
<key-column>Product_ID</key-column>
</column-map>
</relationship-role-map>
· Specify the mapping using <weblogic-relationship-role>
o Specify the role name matching the name in the ejb-jar
§ Example: <relationship-role-name> many-Product@parents-Have-Product</
relationship-role-name>
o Define <relationship-role-map> that defines the mapping of the foreign key to
the primary key mapping
§ Example:
<relationship-role-map>
<column-map>
<foreign-key-column>Child_Product_ID</foreign-key-column>
<key-column>Product_ID</key-column>
</column-map>
</relationship-role-map>
"Thomas A. Valletta" <[email protected]> wrote in message news:[email protected]...
I am attempting to create an EJB that uses Container Managed Persistence,
but my situation seems to be an odd one. The EJB needs to have a
Many-to-Many relationship to itself, because the object is Hierarchical.
Because this is my first EJB I am having a hard time with all of the
deployment descriptors.
I am asking for an example of any Many-to-Many EJB relationship that uses
Weblogic's built-in link table creation to make the relationship (that
works). I realize that there are confidentiality issues with many people
releasing code. I will make any promise (short of selling my soul) that the
code will be safe and promply destroyed immediately after inspection.
Thanks for any help,
Tom
[email protected]
[att1.html]
[ejb-jar.xml]
[weblogic-cmp-rdbms-jar.xml]
[weblogic-ejb-jar.xml]
[ProductBean.java]
[ProductLocal.java]
[ProductLocalHome.java] -
ADF-Newbie.How can I create a many-to-many row from an action method?
Hi all,
First of all, this is my scenario:
- JDeveloper 10.1.3.0.4
- My application is running ADF + Faces + Toplink + EJB Facade
- My database model includes some many-to-many relationships and some one-to-may relationships.
I have developed several ADF pages displaying some CRUD operations over my master tables and my master-detail tables without any problem.
I am now trying to implement some CRUDs over my many-to-many relationship tables.
Lets call the tables involved as master1, master2, and relationship (the many-to-many table)
Because usability reasons, my user wants me to implement an interface where he can:
-Select a row from the master1 table
-Select a row from the master2 table
-Click a button called "Create relationship"
I need to implement the code inside the action button to add my new record on the relationship table, and honestly, I have not found any clue.
Please, give me some directions to solve my problem.
Thank you in advance for your help...The key here is to work with the intersection table for your MtM relationship.
The way I do it, is to have the user view Master Table I, and click on the add Relationship button, this button is a link to a add form for the Intersection Table. On the Add form, the MasterTable 1 Id is already filled in and I hide it. I then setup MasterTable 2 as an LOV on the page. The used selects the item from the LOV and clicks on the commit button. I refresh my many-to-many view and all is grand.
Using ADF/JSF, I have made it even nicer by turning the add relationship page into a dialog page, that way the user can see the previous page while adding the new relationship.
Kelly -
Many-to-many Performance Problem (Using FAQ Template)
Having read "HOW TO: Post a SQL statement tuning request - template posting" I have gathered:
I have included some background information at the bottom of the post
The following SQL statement has been identified as performing poorly. It takes ~160 seconds to execute, but similar (shown below first statement) SQL statements executes in ~1 second.
SQL taking 160 seconds:
SELECT
a.*
FROM
table_a a
INNER JOIN table_a_b ab ON a.id = ab.media_fk
WHERE
ab.channel_fk IN (7, 1);SQL taking ~1 second or less
ab.channel_fk IN (7);Or even:
ab.channel_fk IN (6, 9, 170, 89);The purpose of the SQL is to return rows from table_a that are associated with table_b (not in SQL) through the junction table table_a_b.
The version of the database is 10.2.0.4.0
These are the parameters relevant to the optimizer:
show parameter optimizer;
NAME TYPE VALUE
optimizer_dynamic_sampling integer 2
optimizer_features_enable string 10.2.0.4
optimizer_index_caching integer 0
optimizer_index_cost_adj integer 100
optimizer_mode string ALL_ROWS
optimizer_secure_view_merging boolean TRUE
show parameter db_file_multi;
NAME TYPE VALUE
db_file_multiblock_read_count integer 16
show parameter db_block_size;
NAME TYPE VALUE
db_file_multiblock_read_count integer 16
select sname, pname, pval1, pval2 from sys.aux_stats$;
SNAME PNAME PVAL1 PVAL2
SYSSTATS_INFO STATUS COMPLETED
SYSSTATS_INFO DSTART 07-18-2006 23:19
SYSSTATS_INFO DSTOP 07-25-2006 23:19
SYSSTATS_INFO FLAGS 0
SYSSTATS_MAIN SREADTIM 5.918
SYSSTATS_MAIN MREADTIM 7.889
SYSSTATS_MAIN CPUSPEED 1383
SYSSTATS_MAIN MBRC 8
SYSSTATS_MAIN MAXTHR 1457152
SYSSTATS_MAIN SLAVETHR -1Here is the output of EXPLAIN PLAN:
PLAN_TABLE_OUTPUT
Plan hash value: 3781163428
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1352K| 771M| | 60042 (3)| 00:05:56 |
|* 1 | HASH JOIN | | 1352K| 771M| 27M| 60042 (3)| 00:05:56 |
|* 2 | INDEX FAST FULL SCAN| SYS_IOT_TOP_316310 | 1352K| 11M| | 1816 (4)| 00:00:11 |
| 3 | TABLE ACCESS FULL | TABLE_A | 2190K| 1230M| | 32357 (4)| 00:03:12 |
Predicate Information (identified by operation id):
1 - access(""AB"".""MEDIA_FK""=""A"".""ID"")
2 - filter(""AB"".""CHANNEL_FK""=1 OR ""AB"".""CHANNEL_FK""=7)
Note
- 'PLAN_TABLE' is old versionFor reference, the EXPLAIN PLAN when using
ab.channel_fk IN (6, 9, 170, 89);which executes in ~1 second is:
PLAN_TABLE_OUTPUT
Plan hash value: 794334170
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 143K| 81M| | 58982 (3)| 00:05:50 |
|* 1 | HASH JOIN | | 143K| 81M| 2952K| 58982 (3)| 00:05:50 |
| 2 | INLIST ITERATOR | | | | | | |
|* 3 | INDEX RANGE SCAN| C_M_INDEX | 143K| 1262K| | 1264 (1)| 00:00:08 |
| 4 | TABLE ACCESS FULL| TABLE_A | 2190K| 1230M| | 32357 (4)| 00:03:12 |
Predicate Information (identified by operation id):
1 - access(""AB"".""MEDIA_FK""=""A"".""ID"")
3 - access(""AB"".""CHANNEL_FK""=6 OR ""AB"".""CHANNEL_FK""=9 OR
""AB"".""CHANNEL_FK""=89 OR ""AB"".""CHANNEL_FK""=170)
Note
- 'PLAN_TABLE' is old versionHere is the output of SQL*Plus AUTOTRACE including the TIMING information:
SQL> set autotrace traceonly arraysize 100;
SQL> SELECT
2 a.*
3 FROM
4 table_a a
5 INNER JOIN table_a_b ab ON a.id = ab.media_fk
6 WHERE
7 ab.channel_fk IN (7, 1);
1336148 rows selected.
Execution Plan
Plan hash value: 3781163428
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1352K| 771M| | 60042 (3)| 00:05:56 |
|* 1 | HASH JOIN | | 1352K| 771M| 27M| 60042 (3)| 00:05:56 |
|* 2 | INDEX FAST FULL SCAN| SYS_IOT_TOP_316310 | 1352K| 11M| | 1816 (4)| 00:00:11 |
| 3 | TABLE ACCESS FULL | TABLE_A | 2190K| 1230M| | 32357 (4)| 00:03:12 |
Predicate Information (identified by operation id):
1 - access("AB"."MEDIA_FK"="A"."ID")
2 - filter("AB"."CHANNEL_FK"=1 OR "AB"."CHANNEL_FK"=7)
Note
- 'PLAN_TABLE' is old version
Statistics
10586 recursive calls
0 db block gets
200457 consistent gets
408343 physical reads
0 redo size
498740848 bytes sent via SQL*Net to client
147371 bytes received via SQL*Net from client
13363 SQL*Net roundtrips to/from client
49 sorts (memory)
0 sorts (disk)
1336148 rows processedThe TKPROF output for this statement looks like the following:
TKPROF: Release 10.2.0.4.0 - Production on Mon Oct 1 12:23:21 2012
Copyright (c) 1982, 2007, Oracle. All rights reserved.
Trace file: ..._ora_4896.trc
Sort options: default
count = number of times OCI procedure was executed
cpu = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk = number of physical reads of buffers from disk
query = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows = number of rows processed by the fetch or execute call
ALTER SYSTEM SET TIMED_STATISTICS = TRUE
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.03 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 2 0.00 0.03 0 0 0 0
Misses in library cache during parse: 0
Parsing user id: 21
SELECT
a.*
FROM
table_a a
INNER JOIN table_a_b ab ON a.id = ab.media_fk
WHERE
ab.channel_fk IN (7, 1)
call count cpu elapsed disk query current rows
Parse 1 0.01 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 2 27.23 163.57 179906 198394 0 16
total 4 27.25 163.58 179906 198394 0 16
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 21
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 2 0.01 0.00 0 0 0 0
Execute 2 0.00 0.03 0 0 0 0
Fetch 2 27.23 163.57 179906 198394 0 16
total 6 27.25 163.62 179906 198394 0 16
Misses in library cache during parse: 1
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 0 0.00 0.00 0 0 0 0
Execute 0 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 0 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
2 user SQL statements in session.
0 internal SQL statements in session.
2 SQL statements in session.
Trace file: ..._ora_4896.trc
Trace file compatibility: 10.01.00
Sort options: default
1 session in tracefile.
2 user SQL statements in trace file.
0 internal SQL statements in trace file.
2 SQL statements in trace file.
2 unique SQL statements in trace file.
46 lines in trace file.
187 elapsed seconds in trace file.The DBMS_XPLAN.DISPLAY_CURSOR output:
select * from table(dbms_xplan.display_cursor('474frsqbc1n4d', null, 'ALLSTATS LAST'));
PLAN_TABLE_OUTPUT
SQL_ID 474frsqbc1n4d, child number 0
SELECT /*+ gather_plan_statistics */ c.* FROM table_a c INNER JOIN table_a_b ab ON c.id = ab.media_fk WHERE ab.channel_fk IN (7, 1)
Plan hash value: 3781163428
| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads | Writes | OMem | 1Mem | Used-Mem |
|* 1 | HASH JOIN | | 1 | 1352K| 1050 |00:00:40.93 | 198K| 182K| 209K| 29M| 5266K| 3320K (1)|
|* 2 | INDEX FAST FULL SCAN| SYS_IOT_TOP_316310 | 1 | 1352K| 1336K|00:00:01.34 | 10874 | 0 | 0 | | | |
| 3 | TABLE ACCESS FULL | TABLE_A | 1 | 2190K| 2267K|00:02:45.56 | 187K| 182K| 0 | | | |
Predicate Information (identified by operation id):
1 - access(""AB"".""MEDIA_FK""=""C"".""ID"")
2 - filter((""AB"".""CHANNEL_FK""=1 OR ""AB"".""CHANNEL_FK""=7))Thank you for reading I'm looking forward for suggestions how to improve the performance of this statement.
h3. Backgroud
Many years ago my company made the decision to store many-to-many relationships in our database using pipe delimited fields. An example field value:
'|ABC|XYZ|VTR|DVD|'Each delimited value refers to a unique 'short code' in TABLE_B (There is also a true numeric foreign key in TABLE_B which is what I'm using in the junction table). We regularly search using these column with the following style SQL:
WHERE
INSTR(pipedcolumn, '|ABC|') > 0
OR INSTR(pipedcolumn, '|XYZ|' > 0
...Appropriate indexes have been created over the years to make this process as fast a possible.
We now have an opportunity to fix some of these design mistakes and implement junction tables to replace the piped field. Before this we decided to take a copy of a database from a customer with the largest record set and test. I created a new junction table:
TABLE_A_B DDL:
CREATE TABLE TABLE_A_B (
media_fk NUMBER,
channel_fk NUMBER,
PRIMARY KEY (media_fk, channel_fk),
FOREIGN KEY (media_fk) REFERENCES TABLE_A (ID),
FOREIGN KEY (channel_fk) REFERENCES TABLE_B (ID)
) ORGANIZATION INDEX COMPRESS;
CREATE INDEX C_M_INDEX ON TABLE_A_B (channel_fk, media_fk) COMPRESS;And parsing out a pipe delimited field, populated this new table.
I then compared the performance of the following SQL:
SELECT
a.*
FROM
table_a a
INNER JOIN table_a_b ab ON a.id = ab.media_fk
WHERE
ab.channel_fk IN (x, y, n); -- Can be Many Minutes
--vs.
SELECT
a.*
FROM
table_a a
WHERE
INSTR(OWNERS,'|x|') >0
OR INSTR(OWNERS,'|y|') >0
OR INSTR(OWNERS,'|n|') >0; -- About 1 second seemingly regardlessWhen x, y, n are values that occur less frequently in TABLE_A_B.CHANNEL_FK the performance is comparable. However once the frequency of x, y, n increases the performance suffers. Here is a summary of the CHANNEL_FK data in TABLE_A_B:
--SQL For Summary Data
SELECT channel_fk, count(channel_fk) FROM table_a_b GROUP BY channel_fk ORDER BY COUNT(channel_fk) DESC;
CHANNEL_FK COUNT(CHANNEL_FK)
7 780741
1 555407
2 422493
3 189493
169 144663
9 79457
6 53051
171 28401
170 19857
49 12603
...I've noticed that once I use any combination of values which occur more than about 800,000 times (i.e. IN (7, 1) = 780741 + 555407 = 1336148) then I get performance issues.
I'm finding it very difficult to accept that the old pipe delimited fields are a better solution (ignoring everything other than this search criteria!).
Thank you for reading this far. I truly look forward to suggestions on how to improve the performance of this statement.
Edited by: user1950227 on Oct 1, 2012 12:06 PM
Renamed link table in DDL.Possibly not, I followed the instructions as best as I could but may have missed things.
h5. 1. DDL for all tables and indexes?
h6. - TABLE_A_B is described above and has a total of 2,304,642 rows. TABLE_A and TABLE_B are described below.
h5. 2. row counts for all tables?
h6. - See below
h5. 3. row counts for the predicates involved?
h6. - Not sure what your asking for, I have a summary of data in TABLE_A_B above. Could you clarify please?
h5. 4. Method and command used to collect stats on the tables and indexes?
h6. - For the stats I collected above I have included the command used to collect the data. If you are asking for further data I am happy to provide it but need more information. Thanks.
TABLE_A has 2,267,980 rows. The DLL that follows has been abbriviated, only the column involved is described.
-- DDL for Table TABLE_A
CREATE TABLE "NS"."TABLE_A"
( "ID" NUMBER
--Lots more columns
) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 106496 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "CUSTOMNAMESPACE" ;
-- DDL for Index ID_PK
CREATE UNIQUE INDEX "NS"."MI_PK" ON "NS"."TABLE_A" ("ID")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 29458432 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ;
-- Constraints for Table TABLE_A
ALTER TABLE "NS"."TABLE_A" ADD CONSTRAINT "MI_PK" PRIMARY KEY ("ID")
USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 29458432 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ENABLE;
ALTER TABLE "NS"."TABLE_A" MODIFY ("ID" NOT NULL ENABLE);TABLE_B has 22 rows. The DLL that follows has been abbriviated, only the column involved is described.
-- DDL for Table TABLE_B
CREATE TABLE "NS"."TABLE_B"
"ID" NUMBER
--Lots more columns
) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 106496 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "CUSTOMNAMESPACE" ;
-- DDL for Index CID_PK
CREATE UNIQUE INDEX "NS"."CID_PK" ON "NS"."TABLE_B" ("ID")
PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 16384 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ;
-- Constraints for Table TABLE_B
ALTER TABLE "NS"."TABLE_B" ADD CONSTRAINT "CID_PK" PRIMARY KEY ("ID")
USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
STORAGE(INITIAL 16384 NEXT 16384 MINEXTENTS 1 MAXEXTENTS 505
PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "SYSTEM" ENABLE;
ALTER TABLE "NS"."TABLE_B" MODIFY ("ID" NOT NULL ENABLE);Edited by: davebcast on Oct 1, 2012 8:51 PM
Index name incorrect
Edited by: davebcast on Oct 1, 2012 8:52 PM -
[ADF] Adding/deleting entries in a many-to-many relationship
I am using JDeveloper 10.1.3 and the ADF BC / ADF Model / ADF Faces / JSF technology stack.
For this question, I am using the SRDemo application as an example, specifically the many-to-many relationship between USERS and PRODUCTS (the Staff Expertise relationship), outlined in red in this schema diagram: Image Link
Users may have any number of product expertise areas and many users may have the same product expertise area. For the purposes of this example I have added two reference fields from the PRODUCT table into the ExpertiseAreas VO (Name and Description), outlined in red in this data control palette section: Image Link
I have created a page which shows the details of a user (1), along with a table showing the expertise areas the user has (3), and a table of all the products available (2), numbered on this design page: Image Link and corresponding to the numbered data controls on this data control palette section: Image Link, where 1 is rendered as an ADF Read-only Form, 2 is an ADF Read-only Table with a tableSelectMany element in the selection facet, and 3 is also an ADF Read-only Table.
What I am trying to do is have the tableSelectMany element reflect which of the products are linked to the current user in the expertise areas relationship (by having the checkbox for currently linked products checked), and when you check or uncheck a product's checkbox, it should add or remove the row in the EXPERTISE_AREAS intersection table, respectively (asume for this example that there are default values for Expertise Level and Notes).
So far I have been following the process used in section 19.8 of the ADF Developer's Guide for Forms/4GL Developers, which describes how to set up a selectManyShuttle which implements the adding and deleting functionality. So I have a Client Interface method in the Application Module, updateSkillsForCurrentStaff (described in section 10.6.7.2), and I have a selection listener for the assignment table in the backing bean for the page, which calls the updateSkillsForCurrentStaff method:
public void selectionChanged(SelectionEvent event)
BindingContainer bc = getBindings();
DCIteratorBinding productsIB = (DCIteratorBinding)bc.get("ProductListIterator");
Set keys = getTable1().getSelectionState().getKeySet();
Iterator iter = keys.iterator();
List productIds = new Vector();
while (iter.hasNext())
String product = ((Key)iter.next()).toStringFormat(true);
productsIB.setCurrentRowWithKey(product);
ViewRowImpl productRow = (ViewRowImpl)productsIB.getCurrentRow();
Number productId = (Number)productRow.getAttribute("Id");
productIds.add(productId);
OperationBinding ob = bc.getOperationBinding("updateSkillsForCurrentStaff");
Map pm = ob.getParamsMap();
pm.put("productIds", productIds);
ob.execute();
All of this works, but I can't work out how to link the selection state of the assignment table to the expertise areas that are linked to the user. Also I think the method listing above must be a bit of a hack, but I don't know enough about this to know if there's an easier way of doing it.
Any help is appreciated.Have a look at this example I cooked up for you.
http://radio.weblogs.com/0118231/2006/10/03.html#a739
It might not be the first way one thinks to implement something, but it illustrates a very interesting, model-centric approach to the problem you propose.
My feelings won't be hurt if you prefer a more view-centric approach, but I wanted to illustrate what was a maximally-model-centric solution (in fact, which doesn't even require a backing bean!) If you like a more view-centric approach, I can help you figure out what's wrong with your key-handling above. For one, I would probably start by passing the Set of Key's directly to the middle tier application module method to eliminate client-side code.
Check it out and let me know what you think. Try it directly in the Business Components Tester to appreciate one of the benefits a model-centric solution can bring. -
Self referencing VO in an ADF Tree
Hi @all
i want to create an ADF Tree and found the following helpful example:
ADF Code Corner sample #32 show how to build a tree table from a self referencing VO:
[http://www.oracle.com/technetwork/developer-tools/adf/learnmore/index-101235.html#CodeCornerSamples]
But i still have two questions:
1. How can i concatenate two attributes in the View Instance?
Table looks like
ID ParentID OrderNo ShortText
====================
1 (null) 10 Text1
2 1 20 Text2
3 2 30 Text3
4 1 50 Text4
The result should be 10.20.30.
2. For the first tree-level the change of the ShortText attribut works fine:
OrderNo: 10 -> Text1
OrderNo: 50 -> Text4
(Tree->SelectionListener: #{bindings.WicNodeView1.treeModel.makeCurrent}
RichTextEditor -> partialTrigger: t1 (the Tree))
But not for the Sub-Levels:
The Problem is OrderNo 30 shows also Text1 (and not Text3).
Do i have to write a method (bean) for the Selection Listener or is there another (shorter) way (i am using Oracle JDeveloper 11.1.2.1.0)?
Thanks for your help!
GregorHi,
this should work the same. You create a tree from a POJO Data Control based on your POJO Model. Expose another collection pointing to the same data set and drag it as the form. Use the setting on the tree configuration dialog to set the current row in the tree as the current in the form iterator.
Frank -
I have a self-referencing table (a Topic can be a response to another Topic) and read one of Frank Nimphius' blogs on this subject, posted on the ADF board for advise. As a result I created the read-only ViewObject to set up this tree relationship and set it to be exposed to the App Module.
Do I need to do more to it than that for JHeadstart to generate the right page defs? Any advise on setting this up cleanly? My user interface must present a page in which users can post new Topics, view topics in a heirarchy (response thread, like in this forum) and respond to Topics or responses. A response is a Topic that references another (parent) Topic. I have to believe this has been done before a million times but am not sure myself how to do it.
Thanks!Steve,
I've read the section and am getting this error:
(oracle.jbo.SQLStmtException) JBO-27122: SQL error during statement preparation. Statement: SELECT Topic.SUBJECT, Topic.ROW_ID, Status.STATUS_CHOICE, Status.ROW_ID AS ROW_ID11, Topic.CREATED_BY, Topic.CREATION_DATE, Response.SUBJECT AS SUBJECT1, Response.CREATION_DATE AS CREATION_DATE1, Response.ROW_ID AS ROW_ID12, Response.CREATED_BY AS CREATED_BY1 FROM TOPIC Topic, RESPONSE Response, STATUS Status WHERE (Topic.ROW_ID = Response.MASTER_ID (+)) AND (Topic.TOPIC_STATUS_ID = Status.ROW_ID) CONNECT BY PRIOR Topic.ROW_ID = Response.MASTER_ID (+) OR Response.ROW_ID = Response.MASTER_ID (+) ORDER BY SUBJECT,CREATION_DATE1
----- LEVEL 1: DETAIL 0 -----
(java.sql.SQLException) ORA-01436: CONNECT BY loop in user data
I have a table called Topic with a Pk called ROW_ID and another table called Response with a Pk called ROW_ID and an Fk called MASTER_ID. A Topic can have many Responses and a Response can also have many Responses. The parent ID could point to either a Topic or a Response. There's no limit on how many levels this can continue. There's a Status table also from which I want to show the text value of the Status for the Topic row (not the Status ROW_ID)
I have a View Object including entities: Topic, Response & Status
I tried the SQL query as:
(Topic.ROW_ID = Response.MASTER_ID (+)) AND (Topic.TOPIC_STATUS_ID = Status.ROW_ID) CONNECT BY PRIOR Topic.ROW_ID = Response.MASTER_ID (+) OR Response.ROW_ID = Response.MASTER_ID (+)
Hoping to have this result:
Topic A
-Response A (to Topic A)
--Response B (to A)
---Response C (to B)
-Response D (to Topic A)
Topic B
Topic C
What am I doing wrong?
Is there a guide that explains better using JHeadstart with JDeveloper (rather than Oracle Designer, which we don't use)? The developer's guide for JHeadstart is hard to translate for use with JDeveloper...
Thanks!! -
Portal Form for a Many to Many relationship
I have 3 tables (well there are actually more but i'm glad when i can do the trick with 3 at the moment):
T_JOURNAL (JOURNAL_ID, JOURNAL_NAME)
T_CONTENTBROKER (CONTENTBROKER_ID, CONTENTBROKER_NAME)
HT_JOURNAL_CONTENTBROKER (JOURNAL_ID, CONTENTBROKER_ID)
The HT stants for 'help table'. T_JOURNAL and T_CONTENTBROKER have a many to many relationship. So one Journal can have many Broker and one Broker has many Journals.
When doing a Form in Oracle Portal for adding a new Journal, i'd like to have a LoV with the Brokers. But an new entry would at least require 3 tables to update (T_JOURNAL, T_CONTENTBROKER and the help table HT_JOURNAL_CONTENTBROKER). How can this be solved? i'm not very good with pl/sql... so if there is only a solution with pl/sql i would be glad for the code...
I also tried to create a view wich would show me the journal with all its broker but i kind of failed...
any suggestions appreciated ;)
- renatoThanks for the info. I tried that and it still doesn't pull the value. I have opened a TAR via metalink, but I'm not getting any
satisfactory answers. I ran across an note - 137172.1 that has this snippet of information in it.
Unfortunately, at this time (portal 3.0.7.6.2) , a non-table item cannot be
referenced in a plsql event handler, only in client side JavaScript code. This
is a known limitation and will be fixed in a future release.
I don't know how to get the value from the client side JavaScript code to a pl/sql variable. Do you?
I've been trying to get them to tell me if the 'known issue' has been addressed in 3.0.9.
I'll keep at it. Thanks so much for your suggestion I appreciate it.
Deb
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