Remove Null from For loop of ArrayList

I am currently converting an ArrayList to a String to send it to a DB so I can retrieve it on the other end and convert it back to an ArrayList later. My thought process is to convert it to a string …

Query Java doesn’t execute

I’m trying to execute a query on eclipse at my Java program, but it always exit with a exception and don’t execute the query, I read a lot of posts here but no one of them could help me with this. …

Get previous months first and last date

I need to query last month data from a database. So I need the first and last date of previous month to be able to make the “between” SQL query. First date starts always from 1 of course, …

SQL query is only returning one entry, when it should be returning several

I am creating a book tagging system and I am trying to call all the books with the same tag. My query is only turning up the first book, and not any of the following books with the same tag. Here is …

Is it possible to create a prepared statement and reuse it later with Java under postgres?

I am trying to test a few things out with postgres. I want to know if it’s possible to create define a PreparedStatement such as String statement = “Insert into table_one values (?)”; …

JOOQ materialized views

is it possible to create materialized views using the JOOQ builder? Something like this DSL.createMaterializedView().execute()

Load the ResultSet of query in dataframe using Spark / java

I want to load the Result Set of a select query in dataframe Spark. I’m using the following code : public static void func (Dataset df){ df.repartition(20); //one connection per …

Apache Flink – External Jar

i’m trying to create a Flink application using maven and an extra dependency : com.microsoft.sqlserver mssql-jdbc</…

What to use: sql migration or entity setups in Spring/Hibernate?

I am little confused, when see, why most programmers use annotation-based setup for database table constraints. For example @Column(unique=true, nullable=false) Why do we need that, if(as I heard) …

Prepared statement with some where condition in case of any value

I have prepared statement like select * from books where author = ? and theme = ? and i cant figure out what to do, if user select option “any author” or “any theme”, what should i set to prepared …