unique-constraint

问题 I only just noticed that each uniqueness constraint in CoreData can have multiple attributes (comma,separated,properties). I don't actually know what it does to have multiple attributes in one constraint though. Does it mean that if any of them are unique then the constraint is not broken? The Apple documentation is not particularly helpful: Constraints: After adding attributes as shown in Configuring Attributes, optionally enter the name of an attribute (or comma-separated list of attributes

问题 I am using Remote Attribute validation The method is invoked successfully on textchange event. However, the parameters in the action method of the controller does not get the value of the field. Here is the Action Method in the HomeController.cs. When invoked the Name parameter remains null . I will be pleased if someone solve this problem [AcceptVerbs("Get", "Post")] public async Task<ActionResult> IsExist(string Name) { List<Keywords> keywords = new List<Keywords>(); HttpClient client =

问题 I am trying to model a simple tree structure in my database. I have a TreeNode table with the following columns: Id (int), Name (string), ParentId (int, nullable), ChildPosition (int) ParentId is a FK to a parent TreeNode, and ChildPosition is the TreeNode's position relative to its siblings: - Parent -- Child 1 (ChildPosition = 0) -- Child 2 (ChildPosition = 1) -- Child 3 (ChildPosition = 2) I'd like to place a composite unique constraint/index on the Parent + ChildPosition columns, because

问题 Assume the following table: CREATE TABLE zoo ( cage INTEGER, animal TEXT, ); Is there a real, effective difference between: ALTER TABLE zoo ADD CONSTRAINT x EXCLUDE USING gist (cage WITH =, animal WITH =) and: CREATE UNIQUE INDEX ON zoo(cage, animal) ? 回答1: I read this on the blog of the author of the exclude constraints: http://thoughts.davisjeff.com/2010/09/25/exclusion-constraints-are-generalized-sql-unique/ DROP TABLE IF EXISTS a; CREATE TABLE a(i int); ALTER TABLE a ADD EXCLUDE (i WITH =

问题 My Swing applications throws few exceptions. I tried to catch Integrity Constraint Violation Exception and display message "Duplicate ID". But when that happened, without catching it here: catch(MySQLIntegrityConstraintViolationException ex) it goes to catch (SQLException ex). What I want to do is, catch Integrity Violation exception and display user friendly message instead of technical message comes from ex.getMessage(). How do I do this? ShippmentTransfer shipTrns = new ShippmentTransfer

问题 A table contains the following data, is using INNODB , has a UNIQUE constraint on position/fk , and doesn't allow NULL for position . +----+----------+-----+ | id | position | fk | +----+----------+-----+ | 1 | 1 | 123 | | 2 | 2 | 123 | | 3 | 3 | 123 | | 4 | 4 | 123 | | 5 | 5 | 123 | | 6 | 6 | 123 | | 7 | 7 | 123 | | 8 | 8 | 123 | | 9 | 9 | 123 | | 10 | 10 | 123 | +----+----------+-----+ PHP receives a request to update the table to the following. The format of the request can be provided how

问题 This question have been asked by several people but my problem seems to be different. Actually I have to merge same structured tables from different databases in postgresql into a new DB. What I am doing is that I connect to remote db using dblink, reads that table in that db and insert it into the table in the current DB like below INSERT INTO t_types_of_dementia SELECT * FROM dblink('host=localhost port=5432 dbname=snap-cadence password=xxxxxx', 'SELECT dementia_type, snapid FROM t_types_of

问题 My Razor 3 web app is creating multiple rows for the same foreign key Id, when multiple input comes in for the same Id, and I would like help on how to avoid this. The SQL Server table stores data about records in another table (it's ratings users have given about certain things, where there is also a table of users and a table of rate-able things, so the ratings table has a foreign key id for user, a foreign key id for the thing rated, and a value for the rating). When no rating has been

问题 I'm new in Neo4j an I need some help. I'm trying to make constraint in multiple properties of nodes at once per two meanings: I need to specify as constraint many properties without typing again and again all over the properties with the command I need to define many properties as ONE- UNITY constraint like in SQL when 3 attributes is a primary key and not separably. How can I achieve it? 回答1: You are actually asking 2 questions. The APOC procedure apoc.schema.assert is helpful for

问题 EDIT: I seem to get the error listed below on every insert no matter what data I try to insert. So maybe my table was corrupted or something? Anyway, here's my question: I have a MySQL table CREATE TABLE `AcpConfig` ( `ndss_id` int(11) NOT NULL default '0', `acp_id` int(11) NOT NULL default '0', `run_date` date NOT NULL default '0000-00-00', `hw_5_threshold` tinyint(1) NOT NULL default '0', `stp_on` tinyint(1) NOT NULL default '0', `sort_on` tinyint(1) NOT NULL default '0', `afcs_ocr_message