unique-constraint

问题 I have a table with a column that must have UNIQUE values (but it could be also a multiple-column UNIQUE index, the problem is the same). In my PHP script I have to insert a row in that table. I'm searching for a way, not MySQL-specific, to exit the PHP script if there's a problem, and the problem is not a violation of a UNIQUE constraint. To make things more easy I don't want to use a SELECT query before :D Currently I'm doing something like this: try { $stmt = $dbh->prepare($someinsertquery

问题 I wonder if anyone can help me with this. I ran the whole thing in sql but its gives me this error: Error report: SQL Error: ORA-00001: unique constraint (GAMES.ATHLETE_PK) violated 00001. 00000 - "unique constraint (%s.%s) violated" *Cause: An UPDATE or INSERT statement attempted to insert a duplicate key. For Trusted Oracle configured in DBMS MAC mode, you may see this message if a duplicate entry exists at a different level. *Action: Either remove the unique restriction or do not insert

问题 How can I create unique constraint when I need to treat null values as equals. For alter table T1 add constraint T1_UN unique (nvl(C1, ' ')) i get ORA-00904: : invalid identifier points on nvl Thanks! 回答1: NOT NULL seems like a better idea, but you could make a function-based index unique: create unique index idx_t1 on t1 (nvl(C1, ' ')); 回答2: Just make the column NOT NULL . The nature of NULL is that it is never equal to anything. Hence every NULL value in your column is already UNIQUE in a

问题 Here is a code for trigger and it have a for loop. When trigger is fired (INSERT OR UPDATE) there's another table data must include it is MICL_SUP OPEN projMgrsCursor; LOOP FETCH projMgrsCursor INTO projMgr; select micl_sup_id_seq.nextval into SUPID from dual; insert into MICL_SUP VALUES ((SUPID), (SELECT SYSDATE FROM DUAL), :NEW.ENTRYADDEDBY_EMP_NO, 3000, 0,projMgr, NULL,:NEW.EMP_NO); END LOOP; CLOSE projMgrsCursor; This is the table structure. Sup_ID primary and unique key . I can't make

问题 What I want to do: Add a unique constraint on the attribute photoID in the entity PhotoUpload . Problem: I tap on constraints and add photoID . When I navigate to a different file and come back to the xcdatamodeld file, the constraint is not present. It is automatically removed. And so the unique constraint is not working. What I have done so far: I have tried deleting the xcdatamodeld file and re-created it, but the same problem persists. Screenshot: Versions: Xcode - 7.3.1 回答1: I believe

问题 I have a table, something like FieldsOnForms( FieldID int (FK_Fields) FormID int (FK_Forms) isDeleted bit ) The pair (FieldID,FormID) should be unique, BUT only if the row is not deleted (isDeleted=0). Is it possible to define such a constraint in SQLServer 2008? (without using triggers) P.S. Setting (FieldID, FormID, isDeleted) to be unique adds the possibility to mark one row as deleted, but i would like to have the chance to set n rows (per FieldID,FormID) to isDeleted = 1, and to have

问题 I use session.merge in SqlAlchemy to insert data to the table with UniqueConstraint , which is common for several columns, for example, my ORM class has the following: UniqueConstraint("attr_1", "attr_2", "attr_3", name="attributes_uix") Should I use filter or filter_by with _and to check, if data, which I'm going to insert will violate this unique constraint, or is it the proper way to catch IntegrityError by try - except construction? 回答1: No an sql-alchemy expert but have struggled with

问题 I'm using Sybase ASE 15.5 and a stranger to this database. Straight to the point--> I'm looking for a sql query that would help me get the primary keys for all tables in sybase along with the column names on which the primary key is declared. For example, if I have the following tables, organization having primary key PK_org_id on the column org_id org_alias having primary key PK_alias_id on the column alias_id org_temp having primary key PK_org_temp_id on the columns (org_id,org_name) then

问题 Is there a way in postgres to create a constraint that works like so: I have an entity that has a value "time_of_day". This value can either be morning, afternoon, evening, day, night or anytime. SO I am trying to figure out how to allow the following combinations: Anytime (cannot have anything else) i.e. there can only be one row if anytime is chosen Morning, or Afternoon - can be many rows, but none can contain 'Anytime'. Also cannot be two rows of the same type e.g. two 'morning' rows. (2)

问题 On insert I am catching the unique constraint mysql_errno() 1062. This works fine but I want to find the existing row to re-instate or modify it. Is there are method to obtain the row id on insert fail? I tried mysql_insert_id() but realised that would only return the row I'm inserting (or failed to insert) therefore, I get 0. Is there no option but to issue another mysql_query and simply perform a select on the duplicate value? I just want to make sure there is no better, quicker, more