Posts tagged sql
ADF: The best way to indicate for records in a table the existence of details – or: the importance of up-to-date SQL knowledge
3An interesting discussion arose in one of the projects I am involved in. The functional requirement at stake: show records in a table. In one of the columns, show an indicator (checkbox for example) that signals whether or not that particular record has a specific type of details associated with it. You could say that it was the equivalent of a table of Departments with a checkmark for each Department that has employees (or employees of a certain type).
There are several ways of doing this – and several tiers in the application at which it can be done. One fairly straightforward way in ADF BC would be to create a ViewObject for the detail records, link them through a ViewLink to the master-VO and create a Transient Attribute in the master VO that uses a Groovy expression to count the number details.
However, when discussing the best approach, we came across other options and then took the discussion to a more generic level. One of my favorite guidelines, useful in situations like this, is to not bring data to where it is not really needed. In this, on the middle tier we do not really need the detail records. All we need is an indication of the existence of the detail records, More >
2 dagen seminar door Steven Feuerstein: Best of Oracle PL/SQL (8 en 9 december)
0Steven Feuerstein
In dit tweedaagse seminar neemt Steven Feuerstein je mee ver voorbij de basismogelijkheden van PL/SQL. Steven zal tijdens dit seminar de best practices behandelen die hij op tientallen plekken in de wereld heeft verzameld en die hij ook mede door zijn nauwe samenwerking met het PL/SQL product team van Oracle kan verifiëren en aanscherpen. Hij laat via code-voorbeelden en interactieve sessies zien hoe je als ontwikkelaar in staat bent om snel, hoogwaardige, goed onderhoudbare en uitbreidbare applicaties kunt maken.
Er is tijdens dit seminar voldoende ruimte om vragen te stellen en ideeën met Steven Feurestein uit te wisselen.
Bij dit seminar zijn de volgende zaken inbegrepen:
- Een exemplaar van het boek Oracle PL/SQL Programming (5th edition) van Steven Feuerstein (twv €71,-).
- Een PL/SQL quiz onder leiding van Steven Feuerstein met leuke prijzen.
- Ook ontvang je een gratis jaarabonnement op het PL/SQL Channel. Hiermee heb je toegang tot 27 uur videotraining (normaal $395).
Dit is de kans om in Nederland in een select gezelschap met één van de experts op PL/SQL gebied kennis te maken en je expertise in  Oracle PL/SQL verder te vergroten. Meer More >
OOW 2011 – What's New, Improved and Coming in Oracle Application Development
0
Currently at Tom Kyte’s session regarding topics new, improved or coming in Oracle Application Development. Tom told about the history APEX has gone thru and the current setup with the APEX Listener and even the “PL/SQL Gateway” was mentioned. I always have to laugh a bit because this last one touches the XDB Protocol Server which can do way more then only this PL/SQL extension for APEX which has been embedded in this XDB Protocol Server framework. There is a APEX book out there that touches a bit the possibilities of the framework, one of the reasons I will promote and explain it a bit more during conferences like UKOUG, because I think its a shame that people don’t know its full potential. Anyway. Tom stressed once again that APEX is a serious environment regarding the huge websites out there based on APEX supporting 1000th of user sessions. Also it nowadays had a better debug support (4.1) and use / support for ROWID, improved data upload and calendar wizard support and redesigned websheets in APEX 4.1.
Data Integriteit anno 2011 – Hands-on met Toon Koppelaars en RuleGen 3.0 bij AMIS op dinsdag 27 september
0datum: dinsdag 27 september; 16.30 uur
locatie: AMIS, Edisonbaan 15, Nieuwegein
sprekers: Toon Koppelaars en Lucas Jellema
Het belang van data integriteit behoeft geen toelichting – als het goed is. Vrijwel iedere enterprise applicatie is gebouwd op het fundament van een database. Robuustheid van die database en absolute betrouwbaarheid van de gegevens daarin zijn. essentieel. Het garanderen van die integriteit en robuustheid is lang niet altijd goed geregeld – en is ook geen triviale uitdaging.
De veelheid van toegangskanalen tot de database – batch jobs, web services, web applicaties in Java en .NET, PL/SQL modules en natuurlijk TOAD voor de applicatie beheerder – maakt wel duidelijk dat de integriteitsregels voor de data ofwel de business rules niet in de applicaties of in een service bus (alleen) kunnen worden geïmplementeerd. Integriteit in moderne applicatie-landschappen kan alleen worden gegarandeerd met implementatie van de business rules in de database zelf.
De Oracle database biedt naast de integrity constraints voor primary, unique en foreign keys weliswaar een veelheid aan mechanismen en constructies maar geen concrete, eenduidige, robuuste en More >
Update day to second interval column in selection from time gaps table by parsing strings containing time differences using REGEXP_SUBSTR
2An apparently trivial challenge that still took me bit longer than expected. What is the situation: I have a table with two columns (of interest). One is a column called gap, with values like these:
Each value represents a time difference. These values are strings – not much use to calculate with. Therefore a second column in the table – called timegap – is defined, of type INTERVAL DAY TO SECOND. The challenge I am facing is to set the value of this column timegap based on the time difference described by the string in column gap.
With a little bit of SQL agility, using for example some regular expressions and an interesting update on [the result of] an inline view, it turns out to be doable in a fairly simple SQL statement.
RuleGen 3.0 – the latest, leanest and most robust solution for complex data constraints in an Oracle Database
0No matter how complex the enterprise and application architectures become, no matter the number of tiers, services, devices and user interfaces – at the heart of most enterprises will be a relational database.
And no matter how hard we try to implement a fully service based architecture or a multi-purpose business tier (for example using EJBs) – we will have multiple routes to the database and the data in it. Data will be manipulated through web applications, web services, client/server applications, batch database jobs, application managers working directly against the database from the command line or TOAD-like tools. If for no other reason – that by itself is an overridding motivation for enforcing every data constraint at the lowest possible level – the one level that none of these channels can avoid: the database itself. In addition to the fact that only enforcement inside the database can provide real integrity (and what the hack would be semi-real integrity?), for most data rules (especially complex ones) implementation inside the database is the most performant, scalable, maintainable, managable, agile, elegant and easy to implement as well.
Note: I am not advocating that More >
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