c# - Why is the unique constraint missing when filling the datatable? -


i have following table in sql server

projects    id(pk, int, not null)    name (varchar(255), not null)    public_key_token (varchar(50), null)

i have added unique constraint name column using

alter table dbo.projects   add constraint name_unique unique (name);

which results in unique, non-clustered index on table (trusting ssms).

in code i'm retrieving table data using

using (sqldataadapter adapter = new sqldataadapter("select * " + dbtabname, con)) {     using (datatable table = new datatable(dbtabname))     {          datatable dt = adapter.fillschema(table, schematype.source);          pkcolumns = dt.primarykey.select(c => c.columnname).tolist();          autoincrementcolumns = dt.primarykey.where(c => c.autoincrement).select(c => c.columnname).tolist();          uniquecolumns = dt.columns.cast<datacolumn>().where(c => c.unique).select(c => c.columnname).tolist();           ...     } }

the pks , autoincrement columns ok in uniquecolumns pk column again. name column arrives in c# without unique constraint.

changing schematype mapped did not alter result.

why lose constraint on way c#? missing on sql server side or in c#?

[update] @tim-schmelter's answer solves problem half way.

just adding index did not work. adding index when pk on id column exists doesn't work.

the way got work delete table, recreate without key , indexes , add unique index in tim's answer. however, after adding pk id column once more i'm old behaviour id listed unique column. weird.

use create unique index or use the gui of ssms.

create unique nonclustered index [name_unique] on [dbo].[projects] (     name asc )

you have added unique constraint not unique index.

your code retrieves uniquecolumns(the single column name).


Comments

Post a Comment

Popular posts from this blog

PHP and MySQL WP -

i trying accomplish 2 things here code. writing php directly wp page using insert php plugin. 1) query mysql database , return results 1 column 4 columns. 2) make each result own hyperlink directs user new wp page runs new query on page. i able query show results , turn results dynamic hyperlink, cannot formatting down. right returns result 1 column. here have: [insert_php] $servername = "localhost"; $username = "login"; //edited privacy $password = "password"; //edited privacy $database = "database"; //edited privacy // create connection $conn = new mysqli($servername, $username, $password, $database); // check connection if ($conn->connect_error) { die("connection failed: " . $conn->connect_error); } echo "connected successfully"; //get results database $result = mysqli_query($conn,"select mine mines order mine"); $all_property = array(); //declare array saving property //showing proper...
Read more

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m...
Read more

go - golang pprof for c library code -

i have been trying profile golang application pprof, seems details of c code(linked static library) missed in output result. flame graph from frame graph can see c code time consuming reported within "runtime._externalcode", no details @ all. , sure static library compiled debug enable. so there way make pprof details(like stack trace) of 3rd party c code? or there other golang profiling tool this?
Read more