I am using the scalikejdbc library to access my Postgres database. The driver I am using is the default org.postgresql.Driver. I am trying to introduce query/result caching but I cannot find any evidence whether scalalike does this by default or if it even supports this. I skimmed through the TypesafeConfigReader class but could not find any configuration property indicative of such a functionality. My last resort would be to implement a simple application level cache but I want to know if this is supported somehow by default. In their official docs I could not find something definitive either.
The question was answered in the scalikejdbc issue tracker. So I'm quoting
There is no built-in query cache/result support at this moment. I would suggest using a different cache library such as https://github.com/cb372/scalacache to reduce method calls.
I'm running a Camel application on Liberty Profile server. I'm taking a message from a queue, unmarshalling, mapping then marshalling. This was working fine but now I'm getting an error that JAXBDataBinding method getContextualNamespaceMap is not found.
I think this is because there is an older version of the jar in the server libs but I don't know why it started using it.
IBM Jar: com.ibm.ws.org.apache.cxf-rt-databinding-jaxb.2.6.2_1.0.12
The issue is resolved if I switch to parent last class loading but its a very hacky way to fix it and is not a great option. Any other ideas? I'm thinking some feature or other dependency in my build may have pulled this jar in.
So it does look like getContextualNamespaceMap is only available in newer versions of the org.apache.cxf-rt-databinding-jaxb JAR than what is available in Liberty.
It might be that parentLast is the best option then. (You already know how to do this but it's documented (here). If it leads to some other issues then do follow-up with another question.
I suppose it's conceivable you might be able to look at whatever is packaged within your application and try removing a set of things and picking them up from the Liberty runtime, to avoid running in parentLast mode. E.g. if you are only referencing getContextualNamespaceMap because you have other code in your app but there is some alternative path you could have gone down entirely in the Liberty-provided modules, then in theory you could be OK.
I'm not familiar enough with the code paths in the modules in the CXF or Camel "stack" to guess whether that's a real-world likelihood though.
The javaee7 feature contained a jaxsw version that clashed with the server version. Removing the javaee7 feature has resolved this issue. Remains to be seen whether or not I will to add it back in.
As some of us have noted, parse.com will be shut down in January 2017. In the current version of parse4cn1, all requests go to https://api.parse.com, using the constant ParseConstants.API_ENDPOINT. Will it be possible to supply a custom URL here, pointing to a different Parse Server? If not, can I build parse4cn1 from source myself? Or should I be looking for an alternative to Parse?
See these related questions:
Will Parse4cn1 still work after Parse server retirement?
parse4cn1 has some issue when working with Node JS and parse-server open source
I now have some time available and intend to make the change you proposed within the coming month or so and make a release that is compatible with the open source Parse server. If that's too late for you, consider making the changes yourself and contributing back via a Github pull request. The Contributing section of the parse4cn1 repo provides useful tips.
Regarding looking at Parse alternatives, that's a decision you'll have to make yourself based on your needs and timeline. My gut feeling is that the Open Source Parse Server will mature and grow in features in the months leading up to the official retirement of Parse.com.
I am currently investigating possible options of a migration framework/tool. I like the idea of ruby migrations on which the above frameworks are based.
So I am asking for your experience, opinions and maybe a comparison between them. Are you using them in production?
thanks for responses. The goal of this question was to get a feeling about which tools is used most in the developer community but it seems that migrations are not a hot topic here.
Anyway, I have decided to go with MigSharp as the codebase seem to be pretty clean and it is quite easy to handle and had build in support for MS SQL CE. Second runner up would have been FluentMigrator where I was not able to produce a working example for compact edition.
Cheers
I use FluentMigrator in production, and am a longtime contributor to FM. I think your question is to general; be more specific. Also, FM has a google group which is fairly active if you want FM information.
FM is derived from migrator.net, as I recall. It uses a fluent-syntax, and supports multiple databases. We have taken some inspiration from rails migrations, but it's definitely not a port. Worth checking out.
One thing I've learned is not to put your migrations in the same assembly as you app code. Separate them into a migration assembly, and use that for migrating your databases.
Also, you should always work on multiple environments to avoid problems with migrations run straight against production. I always have at least a development and production environment, and most of the time there is a testing environment as well.
I use mig#.
It works well, but you will need to have some guidelines for usage - as migrations can get complicated.
We use sequence number on the end of our migrations rather than a date-time stamp. This is because we don't know when the date time stamp was set (when they begun the source code change-set; just before committing; some time inbetween) different developers could use different approaches.
Names such as Migration_0000034.cs give you plenty of space.
At this point, I would stick with migrator.net. I like the promise of FluentMigrator, but it seems to not have any better active development than migrator.net (see the issues and pull requests that have languished on their github site).
There is also no easy way to do an ExecuteScalar(). I'd add it, but I don't want to create my own fork, and I see no reason that a pull request would actually land in the master. (Execute.WithConnection is an Action so it will fire on demand rather than when I need it to fire)
So for me, I'm heading back to migrator.net.
I cannot access ANY database by ANY means from within Delphi XE Professional. What I mean by accessing the data base is:
having the live database appear via
components in the Object Inspector,
when the connected property is set
to true
using the Data Explorer to create
and explore database connections
EDIT:
SORTED !!
The core problem is that communication into the database, including specifically the communication generated by the IDE and any code built using the drivers was problematic.
Confounding and masking sub-issues were:
Missing or misplaced DLLs.
The Data Explorer does not fully support dbExpress drivers.
There is a bug within the 2009 IDE code, found by Chee-Yang Chau when writing the dbxFirebird driver, which limits static linking of drivers into Delphi. It is not known if this bug extends to 2010 or XE.
When using the Object Inspector, it is easy to cause the IDE to revert changed connection parameters to their default values.
Some drivers had incorrect default values (eg assuming the client dll was always gdb32.dll irrespective of whether the database was Interbase or Firebird).
Installation of two versions of Interbase led to some clashes in database communication - server names generated by the tools were odd; and the view of the databases depended on which installation of the Interbase tools were used.
The documentation available is of varying dates; refers to different versions; and as a result often appears contradictory.
END EDIT:
Approaches tried:
Multiple databases
Multiple different drivers/components
Accessing the database through other external tools, such as IBSQL and Flame Robin.
Raising questions (here and here) on SO.
Raising questions on the support forums for Firebird, Embarcardo, and Flame Robin.
Environment:
OS: Windows 7 Ultimate 64bit:
Delphi Embarcadero® RAD Studio XE Professional Version 15.0.3953.35171
Database: W1-V2.5.0.26074 Firebird 2.5 (64 bit)
Connection technology: dbExpress
Delphi Professional does not support Firebird with the native dbExpress drivers that come with Delphi. You need the Enterprise or Architect version of Delphi in order for the native firebird dbExpress driver to work.
I have Delphi 2010 Professional. I didn't want to spend the extra money on the E or A version and I failed to read the feature matrix to see that the Firebird dbExpress driver is not available with the Pro version.
I have found a few really nice videos that show how to connect to Firebird using Delphi. However, when I tried to follow along with my Professonal version nothing worked.
Shame on me and more shame on Embarcadero for touting that Delphi supports Firebird in big bold print but not mentioning that you need the Enterprise or Architect version except in the tiny fine print.
I can now write code to access Firebird within the IDE. I have (limited, but sufficient) access to the drivers within the IDE. Specifically, the drivers appear in the Data Explorer, which can be used to generate default values for the SQLConnection (dbExpress component). These can be accessed and used within the Object Inspector. The workaround to the IDE bug quoted below is necessary to ensure the communication parameters are correct. When writing database code, it is necessary to compile in the source for the dbExpress driver.
The following code is the minimum, with minimum parameter set, necessary to establish and test a database connection:
unit Unit2;
interface
uses Classes, SqlExpr, Dialogs, dbxDevartInterbase;
var SQLConnection1 : TSQLConnection;
implementation
{$R *.dfm}
begin
SQLConnection1 := TSQLConnection.Create(nil);
with SQLConnection1 do
begin
ConnectionName := 'TestConnection';
DriverName := 'DevartInterBase';
LibraryName := 'dbexpida40.dll';
VendorLib := 'fbclient.dll';
GetDriverFunc := 'getSQLDriverInterBase';
Params.Clear;
Params.Add('User_Name=SYSDBA');
Params.Add('Password=masterkey');
Params.Add('Database=localhost:C:\Program Files\Firebird\Firebird_2_5\examples\empbuild\employee.fdb');
Open;
If Connected then ShowMessage('Connection is active');
Free;
end;
end.
The workaround, courtesy of Bob Swart on one of the Codegear forums is:
The trick is to select a
ConnectionName value, which will then
assign a value to the Driver property
and all other properties like
LibraryName, VendorLib and
GetDriverFunc.
Then, make changes - if needed - to
the subproperties of the Driver
property, and finally clear the name
of the Driver property.
This will leave all your changes in
the Params list (which you can also
manually edit if you wish).
Note: leave the ConnectionName set -
if you clear that one, the parameters
will be cleared again.
Now you can compile your application
and deploy it without the need for
dbxdrivers.exe or dbxconnections.ini
(but you need to deploy the DLLs
specified in the LibraryName and
VendorLib, of course).
Also make sure to set LoginPrompt to
False and leave LoadParamsOnConnect
set to False, too.
BOUNTY AWARD
I have awarded the bounty to this answer as it was the one that pointed me away from investigation of the IDE, its installation and configuration, to investigation of the connection into the database.
END
DK about Firebird 64 bit - -no experience. But I've always had a lot of trouble with dbExpress. Never any problem with the included IB components suite. But there is a lot of confusion with IB versions...
But IMO you're best served using the ADO ('DBGo') components as opposed to any proprietary IB or Delphi specific drivers. What you need is an ADO provider for IB, available #:
http://www.ibprovider.com/eng/ - and as others have said, avoid using localhost, use 127.0.0.1, or better still, determine the true IP address of your workstation (ping machine-name...) And are you sure you don't have some kind of firewall or intrustion protection that may be involved?
You also need to make sure that your IB connection is configured properly - local or TCP, and no, don't use quotation marks for your names, pwrds, etc. The error message you got seems to indicate that you're trying to connect via TCP and it's not properly configured. What happened between the time it worked and the time it didn't work? Shut down Delphi? Reboot the machine? Explain please....
No 'special permissions' are needed - you simply need to ensure that your database server and client are properly installed and configured. In terms of functionality you can do everything with the pro version - just that the drivers etc aren't included in the package.
Again, IMO go for ADO and you'll never look back.
HTH,
MNG
Have you tried Paradox via the Borland Database Engine (BDE) and related components: TTable TQuery TStoredProc TDatabase and TSession?
If memory serves me correctly, at least as far back as Delphi 3, the distinguishing factor between "professional" and the "higher-level" editions has been the type of database development "out the box".
In Delphi 1, the BDE was the only way to do out-the-box database development.
Delphi 2 permitted a custom database layer by abstracting parts of the database component hierarchy.
Delphi 3 Professional provided BDE and drivers for file-based databases and Interbase.
One level up (Enterprise?*) they provided BDE drivers for typical client-server database access: SQL Server, Sybase, Interbase, Oracle,... (and native drivers for Interbase)
Another level up (Architect?*) introduced multi-tier development with Midas. Unfortunately, Borland took a step back with Midas, because the multi-tier components were again hard-wired to the BDE. (This was resolved in Delphi 4.)
?* Please note, I may be mistaken about the exact naming of these editions. Around about that time I formed the opinion that Borland was merely coming up with "grander" names in order to charge more for features that didn't really offer as much benefit as the 'big-cheque-writing-CIOs' came to believe - leaving developers to deal with the fallout. (Yes, I have battle-scars from Midas I.)
Rant aside, the theory was....
If one embarked on entry-level database development, you would purchase Delphi ?? Professional. Develop your system against a file-based database or Interbase via the BDE.
If you later needed to scale-up: you would upgrade Delphi, purchase your chosen SQL RDBMS, switch your connectivity via the TDatabase component, and apply the few necessary tweaks.
NOTE: In Delphi 3, you could switch to Native Interbase (personally not recommended) or use third-party components for non-Midas development. From Delphi 4 up, ADO and DevExpress started receiving more attention and nowdays, the BDE seems to be pretty much forgotten.
Of course theory & practice seldom frequent the same pubs. However, with a few cautionary pointers, you should be able to develop a significant file based solution that can be upgraded relatively painlessly.
Keep your business logic out of the database. This is quite possibly the biggest and most frequently encountered error. Huge chunks of systems are often written in triggers and stored procedures, making it more difficult to maintain or migrate a system.
Avoid platform-specific database techniques. This should go without saying, but if you don't explicitly look out for them, you will encounter problems.
Particularly relevant to file based database systems, many support special locking mechanisms - avoid them! They don't scale well to large multi-user systems in any case.
Generating of artificial keys often varies by platform: Generators, IDENTITY columns, how you get the new value.
Plan your system for large volumes of data. Identify the high-transaction tables, and avoid using uncontrolled retrieval of all records. I'd also avoid the TTable in this situation - BDE does a lot of interesting background things with TTable, and behaviour can vary according to driver and platform.
Disclaimer: All this was a long time ago, so some of the details may be a bit sketchy.
Disclaimer2: I don't have any experience with Delphi XE specifically. I currently use D5 professionally, and D2009 in my personal capacity.