we have Spring Hibernate code which generates a Spring JPA data Specification object. This works well (we can use the Specification object to do things like get count). Is there a way to get a plain SQL where-clause from the specification object somehow?
The current code is:
// The line below builds the spec based on business logic. Won't go in the details here, but it is working.
Specification<Crash> querySpec = buildQuerySpec(query);
long count = myDataRepository.count(querySpec);
// Here is what I need: a simple plain T-SQL / Microsoft SQL Server where-clause to be used on other disconnected systems. So something like this:
String whereClause = query.Spec.getPlainSQLWhereClause(...); // e.g. weather in ("raining", "cold") and year in (2014, 2015)
Reason: the specification object (and its related repository) are used in the main system. Now we have other completely disconnected/separate enterprise systems (Esri GIS system), where its APIs can only use plain SQL where-clause.
P.S. I know there's not much code to work with, so some pointers/guides will be much appreciated.
I am using DataTables with the tables being generated in a java controller class that talks to the database. Given a category id, the controller class returns an unknown number of preformatted HTML tables, one for each section in the given category queried. Ideally I would like to display each table as a DataTable on the same page, but unsure if that's possible given that I don't know how many tables I will be getting back so I can't set up their behavior before the query.
Is there a way to format the tables when/as I get them from the controller? I attempted to prepend each table with its own .ready block but that didn't seem to do the trick though I'm fairly new to jQuery and could just be missing something. I used the barest of configuration to try to get it working first
$(document).ready(function(){
$("#results").dataTable({
"bJQueryUI" : true
});
});
$(document).ready(function() {
$('.dataTable').dataTable();
} );
Turns out to work after all, but ONLY if you specify the tables as class="dataTable" which isn't well documented or explained, hopefully this un-confuses someone else!
I have a web application build in Django + Python that interact with web services (written in JAVA).
Now all the database management part is done by web-services i.e. all CRUD operations to actual database is done by web-services.
Now i have to track all User Activities done on my website in some log table.
Like If User posted a new article, then a new row is created into Articles table by web-services and side by side, i need to add a new row into log table , something like "User : Raman has posted a new article (with ID, title etc)"
I have to do this for all Objects in my database like "Article", "Media", "Comments" etc
Note : I am using PostgreSQL
So what is the best way to achieve this..?? (Should I do it in PostgreSQL OR JAVA ..??..And How..??)
So, you have UI <-> Web Services <-> DB
Since the web services talk to the DB, and the web services contain the business logic (i.e. I guess you validate stuff there, create your queries and execute them), then the best place to 'log' activities is in the services themselves.
IMO, logging PostgreSQL transactions is a different thing. It's not the same as logging 'user activities' anymore.
EDIT: This still means you create DB schema for 'logs' and write them to DB.
Second EDIT: Catching log worthy events in the UI and then logging them from there might not be the best idea either. You will have to rewrite logging if you ever decide to replace the UI, or for example, write an alternate UI for, say mobile devices, or something else.
For an audit table within the DB itself, have a look at the PL/pgSQL Trigger Audit Example
This logs every INSERT, UPDATE, DELETE into another table.
In your log table you can have various columns, including:
user_id (the user that did the action)
activity_type (the type of activity, such as view or commented_on)
object_id (the actual object that it concerns, such as the Article or Media)
object_type (the type of object; this can be used later, in combination with object_id to lookup the object in the database)
This way, you can keep track of all actions the users do. You'd need to update this table whenever something happens that you wish to track.
Whenever we had to do this, we overrode signals for every model and possible action.
https://docs.djangoproject.com/en/dev/topics/signals/
You can have the signal do whatever you want, from injecting some HTML into the page, to making an entry in the database. They're an excellent tool to learn to use.
I used django-audit-log and I am very satisfied.
Django-audit-log can track multiple models each in it's own additional table. All of these tables are pretty unified, so it should be fairly straightforward to create a SQL view that shows data for all models.
Here is what I've done to track a single model ("Pauza"):
class Pauza(models.Model):
started = models.TimeField(null=True, blank=False)
ended = models.TimeField(null=True, blank=True)
#... more fields ...
audit_log = AuditLog()
If you want changes to show in Django Admin, you can create an unmanaged model (but this is by no means required):
class PauzaAction(models.Model):
started = models.TimeField(null=True, blank=True)
ended = models.TimeField(null=True, blank=True)
#... more fields ...
# fields added by Audit Trail:
action_id = models.PositiveIntegerField(primary_key=True, default=1, blank=True)
action_user = models.ForeignKey(User, null=True, blank=True)
action_date = models.DateTimeField(null=True, blank=True)
action_type = models.CharField(max_length=31, choices=(('I', 'create'), ('U', 'update'), ('D', 'delete'),), null=True, blank=True)
pauza = models.ForeignKey(Pauza, db_column='id', on_delete=models.DO_NOTHING, default=0, null=True, blank=True)
class Meta:
db_table = 'testapp_pauzaauditlogentry'
managed = False
app_label = 'testapp'
Table testapp_pauzaauditlogentry is automatically created by django-audit-log, this merely creates a model for displaying data from it.
It may be a good idea to throw in some rude tamper protection:
class PauzaAction(models.Model):
# ... all like above, plus:
def save(self, *args, **kwargs):
raise Exception('Permission Denied')
def delete(self, *args, **kwargs):
raise Exception('Permission Denied')
As I said, I imagine you could create a SQL view with the four action_ fields and an additional 'action_model' field that could contain varchar references to model itself (maybe just the original table name).
I have 4 tables involved in this query.
Campaign - many to one business
Business - one to many client
Client - one to one contact
Contact
In contact there is the field contact_name which is unique. I need to retrieve all campaigns related to contact(via client and business) which campaign field type equals 2.
What is the best way to do it with hibernate?
In SQL is will look like this:
select *
from campaign,contact, business, client
where campaign.type=2
and client.contact_id = contact.contact_id
and contact.name = 'Josh'
and client.business_id = business.business_id
and campaign.campaign_id = business.business_id
I think that the following should work.
from Compaign where Compaign.type=2 and compaign.business.client.contact.contact_name=:name
You can execute native SQL Queries too using createSQLQuery() method of Session.
You can also use Scalar Property to avoid the overhead of using ResultSetMetadata.
You can find more information on this from here
I am using the DisplayTag with pagination to display a List objects. The Transactions has a property called 'company' / getCompany() which is the Company object. The Company object contains a String called 'name' / getName().
My code looks like this:
<display:table name="${transactions}" id="transaction" pagesize="2" defaultsort="1">
<display:column property="id" title="ID" href="showTransactionDetails.html" paramId="id" />
<display:column property="company.name" title="Company Name" sortable="true" >
<display:column property="status" title="Status" sortable="true">
</display:table>
Here is the strange part.... Everything works great when the first page is displayed and there are a total of 11 pages with each page containing 2 records.
I can click on a page number and see the page advance. But for some strange reason, when I click on page (2-4) I get an exception:
org.apache.jasper.JasperException:
javax.servlet.ServletException:
javax.servlet.jsp.JspException:
Exception: [.LookupUtil] Error looking
up property "company.name" in object
type
"com.replacements.entity.Transaction".
Cause: null
(It's also important to note that all of the Transaction records contain a value for the company.name since its a required field in my DB)
Is it possible that the company is null. That is, you have a transaction with no company in the database.
I solved it by changing the company property in Hibernate mapping to "lazy=false"
I'm still not sure why the pagination worked from some pages and not all. But this fixed it.
Thank you all for your ideas.
As #Vincent says, likely company is null. You may have a value in your database, but maybe there is an issue where your Transaction class isn't properly reading the db value and setting its company member. Have you tried setting a breakpoint and looking at the Transaction instance?
My first guess is that there is an empty company list. I would suggest you print dump to output your transaction results before they get to the display part.
If that’s not the problem I’ve seen display problems caused by special characters. One of the company names might contain a control character or some other non-displayable character.
Try changing the name="${transactions}" in the display:table tag to name="transactions".
Assuming you have the transactions collection in the session or request or whatever.
The exception message literally tells that the Transaction is null. Thus, there's apparently a null item in the transaction list behind ${transactions}. Look like a fault in the loading/populating logic of the transaction list. Maybe the last item is null? Or maybe the list is request scoped and dependent from some request parameters which are missing in the subsequent request so that loading/populating the list failed?
For the interested, if Company was null as some suggests, EL would not have error'ed that way. It would have mentioned object type Company instead.
A requestURI tag...like so.... requestURI="
Make sure you have setters and getters methods for all attributes in your class and names matching attributes names.