I want to automate SQL statement creation for Oracle, and I've been looking into QueryDSL. I've been successful in creating a query with static columns using the code below.
My aim is to feed in a list of columns into QueryDSL and have them added to the SELECT statement. This would require a new object being created, then added to the SELECT statement and repeated for each column in the list.
From the documentation, it doesn't look like I can add more columns to the SELECT statement after it's been instantiated. I've only been able to create the SELECT statement once; any additional SELECT statements override the previous.
QDRnccell rnccell = new QDRnccell("rnccell");
FTnn0000xxx t032 = new QFTnn0000xxx("t032");
StringPath cellname = Expressions.stringPath(rnccell, "cellname");
SQLQuery sqlQuery = new SQLQuery(conn, configuration);
sqlQuery
.select(t032.starttime,
t032.cyyy.as("tp_0"),
t032.czzz.as("tp_1"))
.from(t032);
I was hoping to add additional columns to the select statement after the sqlQuery was created but as mentioned before, it just gets overwritten.
Related
I am trying to update 2 tables at the same time where the inserted index of the first should be inserted into the 2nd table.
The sql looks like this:
DECLARE #nrTable table (TXT_nr int)
IF NOT EXISTS (SELECT txt FROM tbl1 WHERE txt = (?))
INSERT INTO tbl1 (txt, new) OUTPUT INSERTED.nr INTO #nrTable VALUES((?), 1)
IF NOT EXISTS (SELECT txt FROM tbl1 WHERE txt =(?))
INSERT INTO tbl2 (TXT_nr, field1, field2)
VALUES((SELECT TXT_nr FROM #nrTable), (?), (?))
WHERE field3 = (?) AND field4 = (?)
I am trying to accomplish this using
this.jdbcTemplate.batchUpdate(sql, batch);
simply concatenating the lines in java using basic strings. This seems to only execute the first statement, though.
Now the reason I don´t want to do this transactionally is that I would have to do it using a loop just inserting one batch-object at a time, because of the ouput-clause. This would result in loads of calls to the sql-server.
Is there any known way to accomplish something like this?
You can't use batchupdate in this way. Please refer to this document http://tutorials.jenkov.com/jdbc/batchupdate.html
And to achieve your goal, if you are using a sequence in sql, then you need to get the new value in java and store it in your query. Like this :
long id = jdbcTemplace.queryForObject("select sequence_name.nextval from dual",Long.class);
I am absolutly new in Hibernate and I have the following problem.
I have this standard SQL query:
SELECT count(*)
FROM TID003_ANAGEDIFICIO anagraficaEdificio
INNER JOIN TID002_CANDIDATURA candidatura
ON (candidatura.PRG_PAR = anagraficaEdificio.PRG_PAR AND candidatura.PRG_CAN = anagraficaEdificio.PRG_CAN)
INNER JOIN TID001_ANAGPARTECIPA anagPartecipa ON(anagPartecipa.PRG_PAR = candidatura.PRG_PAR)
INNER JOIN anagrafiche.TPG1029_PROVNUOIST provNuovIst ON (provNuovIst.COD_PRV_NIS = anagPartecipa.COD_PRV_NIS)
WHERE anagraficaEdificio.FLG_GRA = 1 AND provNuovIst.COD_REG = "SI";
This works fine and return an integer number.
The important thing to know is that in this query the only
parameter that can change (inserted by the user in the frontend of a webappplication) is the last one (this one: provNuovIst.COD_REG = "SI").
So, the application on which I am working use Hibernate and the requirement say that I have to implement this query using Hibernate Native SQL, I have found this tutorial:
http://www.tutorialspoint.com/hibernate/hibernate_native_sql.htm
that show this example:
String sql = "SELECT * FROM EMPLOYEE WHERE id = :employee_id";
SQLQuery query = session.createSQLQuery(sql);
query.addEntity(Employee.class);
query.setParameter("employee_id", 10);
List results = query.list();
that, from what I have understand (correct me if I am doing wrong assertion), involves the use of an Employee model class. So th prvious query first define the query (using the :param_name syntax for the parameter), then create an SQLQuery Hibernate object, add the class used for the result, set the previous parameter neam and finally obtain a List (that I think Hibernate create as something like an ArrayList) with the retrieved object.
My problem is that I simply I have to obtain an integer value (because I have a SELECT count(*), so I will obtain an integer value and not a set of rows).
So how can I correctly use the Hibernate Native SQL to implement my SQL query into my Hibernate repository class?
Use SQLQuery.uniqueResult to retrieve a single value from the query:
String sql = "SELECT count(*) ...";
SQLQuery query = session.createSQLQuery(sql);
// set parameters...
int count = ((Number)query.uniqueResult()).intValue();
I'm building a select that has to get me all distinct values from a table.
The sql I would normally write would look like this: "SELECT DISTINCT ARTIST FROM MUSICLIB"
However, ebean is generating the following: "SELECT DISTINCT ID, ARTIST FROM MUSICLIB"
The finder is as such:
find.select("artist").setDistinct(true).findList();
I've found that ebean is generating this ID on every single query, no matter what options I set.
How do I accomplish what I'm looking for?
You can't do that, Ebean for objects mapping requires ID field, and if you won't include it you'll get some mysterious exceptions.
Instead you can query DB without mapping and then write your SQL statement yourself:
SqlQuery sqlQuery = Ebean.createSqlQuery("SELECT DISTINCT artist FROM musiclib");
List<SqlRow> rows = sqlQuery.findList();
for (SqlRow row : rows) {
debug("I got one: " + row.getString("artist"));
}
Of course if artist is a relation, you need to perform additional query using list of found IDs with in(...) expression.
Is it possible to create a sqlite prepared statement in OrmLite?
If so, how to bind the query values which may change across different queries.
Is it possible to create a sqlite prepared statement in OrmLite?
You need to RTFM since ORMLite's online documentation is pretty extensive. If you look in the index for "prepared statement" you find out about the QueryBuilder which #Egor pointed out.
how to bind the query values which may change across different queries.
A little further in that section you learn about select arguments which is how you bind query values that change across queries. This is in the index under "arguments to queries".
To quote from the docs here's how you prepare a custom query:
QueryBuilder<Account, String> queryBuilder = dao.queryBuilder();
Where<Account, String> where = queryBuilder.where();
SelectArg selectArg = new SelectArg();
// define our query as 'name = ?'
where.eq("name", selectArg);
// prepare it so it is ready for later query or iterator calls
PreparedQuery<Account> preparedQuery = queryBuilder.prepare();
When you are ready to run the query you set the select argument and issue the query:
selectArg.setValue("foo");
List<Account> accounts = dao.query(preparedQuery);
Later, you can set the select argument to another value and re-run the query:
selectArg.setValue("bar");
accounts = accountDao.query(preparedQuery);
I have a store program in java and a database made in access. I already have 2 tables in my database which are the customers table and the products table.
I want to add an orders table wherein it's primary key is an autonumber and an order_line table to complete this app. I want to have tables like this..
customer(cust_id, name, ....)
orders(order_no, cust_id, date_purchased,...)
order_line(order_no, product_id, ...)
products(product_id, product_name, price,....)
When the customer purchased the products, i could insert new values to the orders table. The thing that is not clear to me is how could i insert also in the order_line table, because the order_no I created in access is of type autonumber.
Would I make a select statement first to get the order_no value to put it to the order_no in order_line's table? Or I need to put this in one query only.
Anyone with experience to this? Any advice is appreciated.
The insertion into orders and order_line table should happen in a single transaction. While doing so, if you are using plain JDBC to insert record into orders table, you can register the order_no as an OUT parameter in your CallableStatement and get the value after the statement is executed and use to set the order_no attribute on the order_line records.
// begin transaction
connection.setAutoCommit(false);
CallableStatement cs = connection.prepareCall(INSERT_STMT_INTO_ORDERS_TABLE);
cs.registerOutParameter(1, Types.INT);
int updateCount = cs.execute();
// Check the update count.
long orderNo = cs.getInt(1);
// CallableStatement csLine for inserting into order_line table
// for (OrderLine line: orderLines) {
// Set the orderNo in line.
// set paramters on csLine.
// csLine.addBatch();
// }
// run the batch and verify update counts
connection.commit();
// connection.rollback() on error.
The JDBC-way (if you like database-independence), is to use the getGeneratedKeys() method of statement.
Use setAutoCommit(false), then execute the first query with the option Statement.RETURN_GENERATED_KEYS (eg for PreparedStatement).
Then use the getGeneratedKeys() method to retrieve the key (note: reference by column name, as the exact implementation and number of returned columns depends on the driver implementation.
And execute the second statement with that retrieved key.
Finally, commit().