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  • Restricting deletion with NHibernate

    - by FrontSvin
    I'm using NHibernate (fluent) to access an old third-party database with a bunch of tables, that are not related in any explicit way. That is a child tables does have parentID columns which contains the primary key of the parent table, but there are no foreign key relations ensuring these relations. Ideally I would like to add some foreign keys, but cannot touch the database schema. My application works fine, but I would really like impose a referential integrity rule that would prohibit deletion of parent objects if they have children, e.i. something similar 'ON DELETE RESTRICT' but maintained by NHibernate. Any ideas on how to approach this would be appreciated. Should I look into the OnDelete() method on the IInterceptor interface, or are there other ways to solve this? Of course any solution will come with a performance penalty, but I can live with that.

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  • How to get common field in ten tables with different field name

    - by Fero
    Hi all, I am having a common field in ten tables with different field name. example: table1: t1_id     t1_location 1         india 2         china 3         america table2: t2_id     t2_location 4         london 5         australia 6         america Now my o/p should be: location india china america london australia How should i get that using mysql query. thanks in advance

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  • Broken count(*) after adding LEFT JOIN

    - by Iain Urquhart
    Since adding the LEFT JOIN to the query below, the count(*) has been returning some strange values, it seems to have added the total rows returned in the query to the 'level': SELECT `n`.*, exp_channel_titles.*, round((`n`.`rgt` - `n`.`lft` - 1) / 2, 0) AS childs, count(*) - 1 + (`n`.`lft` > 1) + 1 AS level, ((min(`p`.`rgt`) - `n`.`rgt` - (`n`.`lft` > 1)) / 2) > 0 AS lower, (((`n`.`lft` - max(`p`.`lft`) > 1))) AS upper FROM `exp_node_tree_6` `n` LEFT JOIN `exp_channel_titles` ON (`n`.`entry_id`=`exp_channel_titles`.`entry_id`), `exp_node_tree_6` `p`, `exp_node_tree_6` WHERE `n`.`lft` BETWEEN `p`.`lft` AND `p`.`rgt` AND ( `p`.`node_id` != `n`.`node_id` OR `n`.`lft` = 1 ) GROUP BY `n`.`node_id` ORDER BY `n`.`lft` I'm totally stumped... Thank you!

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  • customizing rowsource query in combobox ACCESS

    - by every_answer_gets_a_point
    i have 4 comboboxes and each of them need to have the same query in the rowsource, except there is a slight variation on each query if rowsource = somequery i need it to be select * from somequery where something like 'something1'; the next one needs to be select * from somequery where something like 'something2'; is there a way to customize the rowsource property in this way?

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  • Complicated Order By Clause?

    - by Todd
    Hi. I need to do what to me is an advanced sort. I have this two tables: Table: Fruit fruitid | received | basketid 1 20100310 2 2 20091205 3 3 20100220 1 4 20091129 2 Table: Basket id | name 1 Big Discounts 2 Premium Fruit 3 Standard Produce I'm not even sure I can plainly state how I want to sort (which is probably a big part of the reason I can't seem to write code to do it, lol). I do a join query and need to sort so everything is organized by basketid. The basketid that has the oldest fruit.received date comes first, then the other rows with the same basketid by date asc, then the basketid with the next earliest fruit.received date followed by the other rows with the same basketid, and so on. So the output would look like this: Fruitid | Received | Basket 4 20091129 Premuim Fruit 1 20100310 Premuim Fruit 2 20091205 Standard Produce 3 20100220 Big Discounts Any ideas how to accomplish this in a single execution?

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  • sequence of events in ACCESS

    - by I__
    what is the proper way of doing the following: getting DATE as user input running a query generating a report that uses the query this is the solution i was thinking: have a form that takes user input run the query open the report what is the correct way of doing this?

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  • What are the Limitations for Connecting to an Access Query in Excel

    - by thornomad
    I have an Access 2007 database that has a number of tables, some are fairly large (100,000+ records); I have created a union query to pull some of the same types of data from multiple tables into one large query for pivot table manipulation and reporting. For example: SELECT Language FROM Table1 UNION ALL SELECT Language FROM Table2 UNION ALL SELECT Language FROM Table3; This works. I found, quickly, however, that a union query will not show up when connecting to the datasource from Excel 2007. So, I created a second query to reference the union query. Like so: SELECT * FROM [The Above Union Query]; This query works and it, initially, was accessible from Excel. Time passed, I've added more data. Suddenly, when I connect to my Access database from Excel my query referencing the union has disappeared. MS Access shows no signs of an issue (data displays in Access) and my other non-union queries are showing up in Excel 2007 ... but not the one that references the union. What could be going on? Why did it disappear? I noticed if I switch some of the referenced tables in the union query to a smaller table (with less rows) all of sudden the query appears in Excel again. At least, I think that's what the difference is. I really can't put my finger on why some of the union queries won't show up and some will. Am stumped and need some guidance. Thanks.

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  • How should I build a gaming community

    - by Przystojny
    I've been wanting to build my own gaming community site (like http://fragbite.com) for a long time, I have started many times but just quitted after a couple days because it gets very messy I've been palying around with php and mysql off and on for 3 years but i've never gotten in to oop. i have tried but i usually end up with the "old php". I usually build my pages like so that i include a file on top of all pages with neccasary functions, html head etc. And I mix php and html together which I dont mind but if I eventually would get a designer he would not like it i think. I have tried both phpcake and codeigniter and all those popular mvc's but its just to much, like they do all the work. i want to do it myself. but i dont know where to start. What would you do if you were me? Is there maybe some non-oop mvc? (Sorry for my english)

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  • Need to use query column value in nested subquery

    - by Dustin
    It seems I cannot use a column from the parent query in a sub query. How can I refactor this query to get what I need? dbo.func_getRelatedAcnts returns a table of related accounts (all children from a given account). Events and Profiles are related to accounts. SELECT COUNT(r.reg_id) FROM registrations r JOIN profiles p ON (r.reg_frn_pro_id = p.pro_id) JOIN events e ON (r.reg_frn_evt_id = e.evt_id) WHERE evt_frn_acnt_id NOT IN (SELECT * FROM dbo.func_getRelatedAcnts(p.pro_frn_acnt_id))

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  • MySQL COUNT() multiple columns

    - by liam
    Hello, I'm trying to fetch the most popular tags from all videos in my database (ignoring blank tags). I also need the 'flv' for each tag. I have this working as I want if each video has one tag: SELECT tag_1, flv, COUNT(tag_1) AS tagcount FROM videos WHERE NOT tag_1='' GROUP BY tag_1 ORDER BY tagcount DESC LIMIT 0, 10 However in my database, each video is allowed three tags - tag_1, tag_2 and tag_3. Is there a way to get the most popular tags reading from multiple columns? The record structure is: +-----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | flv | varchar(150) | YES | | NULL | | | tag_1 | varchar(75) | YES | | NULL | | | tag_2 | varchar(75) | YES | | NULL | | | tag_3 | varchar(75) | YES | | NULL | | +-----------------+--------------+------+-----+---------+----------------+

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  • Multiple user database design

    - by dieguitoweb
    I have to develop a basic social network for an academic purpose; but I need some tips for the users management.. The users are subdivided into 3 groups with different privilege: admins,analysts and standards users. For every user should be stored into the database the following information: name,lastname,e-mail,age,password. I'm not quite sure how I should design the database between theese two solutions: 1)one table called 'users' with the 'role' attribute that explain what a user can do and what can't do, and the permissions are managed via php 2)every application user is a database user created with the query 'CREATE ROLE' (It's a postgres database) and he has permissions on some tables granted with the 'GRANT' statement You should take into account that the project is for a database exam.. thanks

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  • Calendar using Javascript/ PHP/ mySQL

    - by Gushiken
    for a current webapp i need a "outlook-like" calendar... Here are some requirements for the calendar: week-view for the appointments different appointment types direct display of the length and time of the date (like in googleCalendar) multiple appointments for the same time only using javascript, php and any DB We need the calendar for the Zend Framework, so if the Calendar doesn't already support the ZF, the source needs to be editable! do you know any calendar which fits my needs? or do you have any tipps for developing one by myself?

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  • Why is SQLite3 using covering indices instead of the indices I created?

    - by Geoff
    I have an extremely large database (contacts has ~3 billion entries, people has ~280 million entries, and the other tables have a negligible number of entries). Most other queries I've run are really fast. However, I've encountered a more complicated query that's really slow. I'm wondering if there's any way to speed this up. First of all, here is my schema: CREATE TABLE activities (id INTEGER PRIMARY KEY, name TEXT NOT NULL); CREATE TABLE contacts ( id INTEGER PRIMARY KEY, person1_id INTEGER NOT NULL, person2_id INTEGER NOT NULL, duration REAL NOT NULL, -- hours activity_id INTEGER NOT NULL -- FOREIGN_KEY(person1_id) REFERENCES people(id), -- FOREIGN_KEY(person2_id) REFERENCES people(id) ); CREATE TABLE people ( id INTEGER PRIMARY KEY, state_id INTEGER NOT NULL, county_id INTEGER NOT NULL, age INTEGER NOT NULL, gender TEXT NOT NULL, -- M or F income INTEGER NOT NULL -- FOREIGN_KEY(state_id) REFERENCES states(id) ); CREATE TABLE states ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, abbreviation TEXT NOT NULL ); CREATE INDEX activities_name_index on activities(name); CREATE INDEX contacts_activity_id_index on contacts(activity_id); CREATE INDEX contacts_duration_index on contacts(duration); CREATE INDEX contacts_person1_id_index on contacts(person1_id); CREATE INDEX contacts_person2_id_index on contacts(person2_id); CREATE INDEX people_age_index on people(age); CREATE INDEX people_county_id_index on people(county_id); CREATE INDEX people_gender_index on people(gender); CREATE INDEX people_income_index on people(income); CREATE INDEX people_state_id_index on people(state_id); CREATE INDEX states_abbreviation_index on states(abbreviation); CREATE INDEX states_name_index on states(name); Note that I've created an index on every column in the database. I don't care about the size of the database; speed is all I care about. Here's an example of a query that, as expected, runs almost instantly: SELECT count(*) FROM people, states WHERE people.state_id=states.id and states.abbreviation='IA'; Here's the troublesome query: SELECT * FROM contacts WHERE rowid IN (SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person1_id=people.id AND people.state_id=states.id AND states.name='Kansas' INTERSECT SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person2_id=people.id AND people.state_id=states.id AND states.name='Missouri'); Now, what I think would happen is that each subquery would use each relevant index I've created to speed this up. However, when I show the query plan, I see this: sqlite> EXPLAIN QUERY PLAN SELECT * FROM contacts WHERE rowid IN (SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person1_id=people.id AND people.state_id=states.id AND states.name='Kansas' INTERSECT SELECT contacts.rowid FROM contacts, people, states WHERE contacts.person2_id=people.id AND people.state_id=states.id AND states.name='Missouri'); 0|0|0|SEARCH TABLE contacts USING INTEGER PRIMARY KEY (rowid=?) (~25 rows) 0|0|0|EXECUTE LIST SUBQUERY 1 2|0|2|SEARCH TABLE states USING COVERING INDEX states_name_index (name=?) (~1 rows) 2|1|1|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) 2|2|0|SEARCH TABLE contacts USING COVERING INDEX contacts_person1_id_index (person1_id=?) (~12 rows) 3|0|2|SEARCH TABLE states USING COVERING INDEX states_name_index (name=?) (~1 rows) 3|1|1|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) 3|2|0|SEARCH TABLE contacts USING COVERING INDEX contacts_person2_id_index (person2_id=?) (~12 rows) 1|0|0|COMPOUND SUBQUERIES 2 AND 3 USING TEMP B-TREE (INTERSECT) In fact, if I show the query plan for the first query I posted, I get this: sqlite> EXPLAIN QUERY PLAN SELECT count(*) FROM people, states WHERE people.state_id=states.id and states.abbreviation='IA'; 0|0|1|SEARCH TABLE states USING COVERING INDEX states_abbreviation_index (abbreviation=?) (~1 rows) 0|1|0|SEARCH TABLE people USING COVERING INDEX people_state_id_index (state_id=?) (~5569556 rows) Why is SQLite using covering indices instead of the indices I created? Shouldn't the search in the people table be able to happen in log(n) time given state_id which in turn is found in log(n) time?

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  • Insert not working

    - by user1642318
    I've searched evreywhere and tried all suggestions but still no luck when running the following code. Note that some code is commented out. Thats just me trying different things. SqlConnection connection = new SqlConnection("Data Source=URB900-PC\SQLEXPRESS;Initial Catalog=usersSQL;Integrated Security=True"); string password = PasswordTextBox.Text; string email = EmailTextBox.Text; string firstname = FirstNameTextBox.Text; string lastname = SurnameTextBox.Text; //command.Parameters.AddWithValue("@UserName", username); //command.Parameters.AddWithValue("@Password", password); //command.Parameters.AddWithValue("@Email", email); //command.Parameters.AddWithValue("@FirstName", firstname); //command.Parameters.AddWithValue("@LastName", lastname); command.Parameters.Add("@UserName", SqlDbType.VarChar); command.Parameters["@UserName"].Value = username; command.Parameters.Add("@Password", SqlDbType.VarChar); command.Parameters["@Password"].Value = password; command.Parameters.Add("@Email", SqlDbType.VarChar); command.Parameters["@Email"].Value = email; command.Parameters.Add("@FirstName", SqlDbType.VarChar); command.Parameters["@FirstName"].Value = firstname; command.Parameters.Add("@LasttName", SqlDbType.VarChar); command.Parameters["@LasttName"].Value = lastname; SqlCommand command2 = new SqlCommand("INSERT INTO users (UserName, Password, UserEmail, FirstName, LastName)" + "values (@UserName, @Password, @Email, @FirstName, @LastName)", connection); connection.Open(); command2.ExecuteNonQuery(); //command2.ExecuteScalar(); connection.Close(); When I run this, fill in the textboxes and hit the button I get...... Must declare the scalar variable "@UserName". Any help would be greatly appreciated. Thanks.

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  • MySQL Query to find consecutive available times of variable lenth

    - by Armaconn
    I have an events table that has user_id, date ('2013-10-01'), time ('04:15:00'), and status_id; What I am looking to find is a solution similar to http://stackoverflow.com/questions/2665574/find-consecutive-rows-calculate-duration but I need I need two additional components: 1) Take date into consideration, so 10/1/2013 at 11:00 PM - 10/2/2013 at 3:00AM. Feel free to just put in a fake date range (like '2013-10-01' to '2013-10-31') 2) Limit output to only include when there are 4+ consecutive times (each event is 15 minutes and I want it to display minimum blocks of an hour, but would also like to be able to switch this restriction to 1.5 hours or some other duration if possible). SUMMARY - Looking for a query that provides the start and end times for a set of events that have the same user_id, status_id, and are in a continuous series based on date and time. For which I can restrict results based on date range and minimum series duration. So the output should have: user_id, date_start, time_start, date_end, time_end, status_id, duration CREATE TABLE `events` ( `event_id` int(11) NOT NULL auto_increment COMMENT 'ID', `user_id` int(11) NOT NULL, `date` date NOT NULL, `time` time NOT NULL, `status_id` int(11) default NULL, PRIMARY KEY (`event_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1568 ; INSERT INTO `events` VALUES(1, 101, '2013-08-14', '23:00:00', 2); INSERT INTO `events` VALUES(2, 101, '2013-08-14', '23:15:00', 2); INSERT INTO `events` VALUES(3, 101, '2013-08-14', '23:30:00', 2); INSERT INTO `events` VALUES(4, 101, '2013-08-14', '23:45:00', 2); INSERT INTO `events` VALUES(5, 101, '2013-08-15', '00:00:00', 2); INSERT INTO `events` VALUES(6, 101, '2013-08-15', '00:15:00', 1); INSERT INTO `events` VALUES(7, 500, '2013-08-14', '23:45:00', 1); INSERT INTO `events` VALUES(8, 500, '2013-08-15', '00:00:00', 1); INSERT INTO `events` VALUES(9, 500, '2013-08-15', '00:15:00', 2); INSERT INTO `events` VALUES(10, 500, '2013-08-15', '00:30:00', 2); INSERT INTO `events` VALUES(11, 500, '2013-08-15', '00:45:00', 1); Desired output row |user_id | date_start | time_start | date_end | time_end | status_id | duration 1 |101 |'2013-08-14'| '23:00:00' |'2013-08-15'|'00:15:00'| 2 | 5 2 |101 |'2013-08-15'| '00:00:15' |'2013-08-15'|'00:30:00'| 1 | 1 3 |500 |'2013-08-14'| '00:23:45' |'2013-08-15'|'00:15:00'| 1 | 2 4 |500 |'2013-08-15'| '00:00:15' |'2013-08-15'|'00:45:00'| 2 | 2 5 |500 |'2013-08-15'| '00:00:45' |'2013-08-15'|'01:00:00'| 2 | 1 *except that rows 2 and 5 wouldn't appear if duration had to be greater than 30 minutes Thanks for any help that you can provide! And please let me know if there is anything I can further clarify!!

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  • Entity Framework EntityKey / Foreign Key problem.

    - by Ronny176
    Hi, I keep getting the same error: Entities in 'VlaamseOverheidMeterEntities.ObjectMeter' participate in the 'FK_ObjectMeter_Meter' relationship. 0 related 'Meter' were found. 1 'Meter' is expected. I have the following table structure: Meter 1 <- * ObjectMeter * - 1 VO_Object It is always the same scenario: The first meter is added to the database, the second meter gives the error above. I have the following code in my manager: public List<string> addTemporary(string username, string meterNaam, string readingType, string parentID) { Meter meter = new Meter(); VO_Object voObject = objectManager.getObjectByID(parentID); ObjectMeter objMeter = new ObjectMeter(); meter.readingType = (int)Enum.Parse(typeof(ReadingType), readingType); meter.isActive = true; meter.name = meterNaam; meter.startDate = DateTime.Now; meter.endDate = DateTime.Now.AddYears(6000); meter.uniqueIdentifier = "N/A"; meter.meterType = (int)Enum.Parse(typeof(MeterType), "NA"); meter.meterCategory = (int)Enum.Parse(typeof(MeterCategory), "NA"); meter.energyType = (int)Enum.Parse(typeof(EnergyType), "NA"); meter.utilityType = (int)Enum.Parse(typeof(UtilityType), "NA"); meter.unitOfMeasure = (int)Enum.Parse(typeof(UnitOfMeasure), "NA"); objMeter.valid_from = meter.startDate; objMeter.valid_until = meter.endDate; objMeter.Meter = meter; objMeter.VO_Object = voObject; createMeter(meter); List<String> str = new List<string>(); str.Add("" + meter.meterID); str.Add(meter.name); return str; } and this in my Dao Class which links to the database: internal void CreateMeter(Meter _meter) { _entities.AddToMeter(_meter); _entities.SaveChanges(); } Can someone please explain this error? Ronald

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  • Help Me With This MS-Access Query

    - by yae
    I have 2 tables: "products" and "pieces" PRODUCTS idProd product price PIECES id idProdMain idProdChild quant idProdMain and idProdChild are related with the table: "products". Other considerations is that 1 product can have some pieces and 1 product can be a piece. Price product equal a sum of quantity * price of all their pieces. "Products" table contains all products (p EXAMPLE: TABLE PRODUCTS (idProd - product - price) 1 - Computer - 300€ 2 - Hard Disk - 100€ 3 - Memory - 50€ 4 - Main Board - 100€ 5 - Software - 50€ 6 - CDroms 100 un. - 30€ TABLE PIECES (id - idProdMain - idProdChild - Quant.) 1 - 1 - 2 - 1 2 - 1 - 3 - 2 3 - 1 - 4 - 1 WHAT I NEED? I need update the price of the main product when the price of the product child (piece) is changed. Following the previous example, if I change the price of this product "memory" (is a piece too) to 60€, then product "Computer" will must change his price to 320€ How I can do it using queries? Already I have tried this to obtain the price of the main product, but not runs. This query not returns any value: SELECT Sum(products.price*pieces.quant) AS Expr1 FROM products LEFT JOIN pieces ON (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdMain) WHERE (((pieces.idProdMain)=5)); MORE INFO The table "products" contains all the products to sell that it is in the shop. The table "pieces" is to take a control of the compound products. To know those who are the products children. For example of compound product: computers. This product is composed by other products (motherboard, hard disk, memory, cpu, etc.)

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  • Oracle: how to "group by" over a range?

    - by Mark Harrison
    If I have a table like this: pkey age ---- --- 1 8 2 5 3 12 4 12 5 22 I can "group by" to get a count of each age. select age,count(*) n from tbl group by age; age n --- - 5 1 8 1 12 2 22 1 What query can I use to group by age ranges? age n ----- - 1-10 2 11-20 2 20+ 1

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  • Looking for MSSQL Table Design Sanity Check for Profile Tables with Dynamic Columns.

    - by Code Sherpa
    I just want a general sanity check regarding database design. We are building a web system that has both Teachers and Students. Both have accounts in the system. Both have profiles in the system. My question is about the table design of those Profile tables. The Teacher profile is pretty static regarding the metadata associated with it. Each teacher has a set number of fields that exposes information about that individual (schools, degrees, etc). The students, however, are a different case. We are using a windows service to pull varying data about the students from an endless stream of excel spreadsheets. The data gets moved into our database and then the fields appear in association with the student's profile. Accordingly, each and every student may have very different fields in their profile. I originally started with the concept of three tables: Accounts ---------- AccountID TeacherProfiles ---------- TeacherProfileID AccountID SecondarySchool University YearsTeaching Etc... StudentProfiles ---------- StudentProfileID AccountID Header Value The StudentProfiles table would hold the name of the column headers from the excel spreadsheets and the associated values. I have since evolved the design a little to treat Profiles more generically per the attached ERD image. The Teacher and Student "Headers" are stored in a table called "ProfileAttributeTypes" and responses (either from the excel document or via input fields on the web form) are put in a ProfileAttributes table. This way both Student and Teacher profiles can be associated with a dynamic flow of profile fields. The "Permissions" table tells us whether we are dealing with a Student or a Teacher. Since this system is likely to grow quickly, I want to make sure the foundation is solid. Can you please provide feedback about this design and let me know if it seems sound or if you could see problems it might create and, if so, what might be a better approach? Thanks in advance.

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  • Has anyone ever successfully make index merge work for MySQL?

    - by user198729
    Setup: mysql> create table t(a integer unsigned,b integer unsigned); mysql> insert into t(a,b) values (1,2),(1,3),(2,4); mysql> create index i_t_a on t(a); mysql> create index i_t_b on t(b); mysql> explain select * from t where a=1 or b=4; +----+-------------+-------+------+---------------+------+---------+------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | t | ALL | i_t_a,i_t_b | NULL | NULL | NULL | 3 | Using where | +----+-------------+-------+------+---------------+------+---------+------+------+-------------+ Is there something I'm missing? Update mysql> explain select * from t where a=1 or b=4; +----+-------------+-------+------+---------------+------+---------+------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | t | ALL | i_t_a,i_t_b | NULL | NULL | NULL | 1863 | Using where | +----+-------------+-------+------+---------------+------+---------+------+------+-------------+ Version: mysql> select version(); +----------------------+ | version() | +----------------------+ | 5.1.36-community-log | +----------------------+ Has anyone ever successfully make index merge work for MySQL? I'll be glad to see successful stories here:)

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  • Do I need to drop index on temp table?

    - by Phil
    Hi, Fairly simple question, but I don't see it anywhere else on SO: Do indexes (indices?) on a temporary table get automatically deleted with the temporary table? I'd imagine they do but I don't really know how to check to make sure. Thanks, Phil

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  • Clustered index on frequently changing reference table of one or more foreign keys

    - by Ian
    My specific concern is related to the performance of a clustered index on a reference table that has many rapid inserts and deletes. Table 1 "Collection" collection_pk int (among other fields) Table 2 "Item" item_pk int (among other fields) Reference Table "Collection_Items" collection_pk int, item_pk int (combined primary key) Because the primary key is composed of both pks, a clustered index is created and the data physically ordered in the table according to the combined keys. I have many users creating and deleting collections and adding and removing items to those collections very frequently affecting the "Collection_Items" table, and its clustered index. QUESTION PART: Since the "Collection_Items" table is so dynamic, wouldn't there be a big performance hit on constantly resorting the table rows because of the clustered index ? If yes, what should I do to minimize this ?

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