postgresql-9.1

Similar to this question , how can I find if a NULL value exists in an array? Here are some attempts. SELECT num, ar, expected, ar @> ARRAY[NULL]::int[] AS test1, NULL = ANY (ar) AS test2, array_to_string(ar, ', ') <> array_to_string(ar, ', ', '(null)') AS test3 FROM ( SELECT 1 AS num, '{1,2,NULL}'::int[] AS ar, true AS expected UNION SELECT 2, '{1,2,3}'::int[], false ) td ORDER BY num; num | ar | expected | test1 | test2 | test3 -----+------------+----------+-------+-------+------- 1 | {1,2,NULL} | t | f | | t 2 | {1,2,3} | f | f | | f (2 rows) Only a trick with array_to_string shows the

I want to port the below SQL code from MS SQL-Server to PostgreSQL. DECLARE @iStartYear integer DECLARE @iStartMonth integer DECLARE @iEndYear integer DECLARE @iEndMonth integer SET @iStartYear = 2012 SET @iStartMonth = 4 SET @iEndYear = 2016 SET @iEndMonth = 1 ;WITH CTE AS ( SELECT --@iStartYear AS TheStartYear @iStartMonth AS TheRunningMonth ,@iStartYear AS TheYear ,@iStartMonth AS TheMonth UNION ALL SELECT --CTE.TheStartYear AS TheStartYear --@iStartYear AS TheStartYear CTE.TheRunningMonth + 1 AS TheRunningMonth --,CTE.TheStartYear + (CTE.TheRunningMonth / 12) AS TheYear ,@iStartYear + (CTE

I have a many-to-one relationship that I want to be nullable: @ManyToOne(optional = true) @JoinColumn(name = "customer_id", nullable = true) private Customer customer; Unfortunately, JPA keeps setting the column in my database as NOT NULL. Can anyone explain this? Is there a way to make it work? Note that I use JBoss 7, JPA 2.0 with Hibernate as persistence provider and a PostgreSQL 9.1 database. EDIT : I found the cause of my problem. Apparently it is due to the way I defined the primary key in the referenced entity Customer : @Entity @Table public class Customer { @Id @GeneratedValue @Column