Install Packages

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Revision as of 07:50, 16 May 2012 by BigChimp (talk | contribs) (Overview: Database components present by default)

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Overview

Due to popular demand here is a small "Install package HOW-TO".

We're going to look at installing database components, which weren't installed by default in old Lazarus versions. They are still not present in the minimal IDE, but are there in the normal IDE. Though database components are nowadays present in Lazarus by default, the concepts of finding and installing packages can still be nicely illustrated.

We are going to look for and install the components to connect to a database (server) and to retrieve data from this database?

Well, let's have a look to see if we can find some of this stuff.

Files installed with Lazarus

Under Linux Lazarus gets installed by default in /usr/bin/lazarus, on Mac OS X Lazarus is installed in /usr/local/share/lazarus, and with Windows the installer gives you a choice where to install the files, as long as there are no spaces in its path. On my Windows PC Lazarus got installed in G:/Lazarus. Whatever the base path of your Lazarus installation is, there you will find some subdirectories. In this case the first (alphabetically) subdirectory looks rather promising as it is called components.

As you can see there are a few subdirectories there, which remind us of databases. One sees an Interbase, a mysql, a sqlite and a sqldb directory. The first three contain database connection components and TDataset descendants for the respective databases. The last one, sqldb, is more generic, as it consists of TSQLQuery (a TDataset) and TSQLTransaction which are used for all types of databases and a T??Connection to make the connection to the database. In this article we will install the sqldb package together with the connection for Interbase.

The real work

First: the why

Before we start installing a package I would like to discuss the why of Lazarus not installing database connection components. Database connection components need the client libraries to be available on the PC where the components are used. Because Lazarus does not currently support dynamic linking, all libraries have to be compiled into the IDE. As you cannot expect every developer to have all databases installed it is not possible to install the connection components by default.

Second: But Delphi ...?

Delphi also only installs the database components which are readily available on the computer (ADO components) and components which do not need any client libraries (BDE: Paradox, DBase) to be installed.

Third: Let's install some stuff

To install a package one goes to "Components -> Open Package File (.lpk)". In the following dialog you navigate to /usr/share/lazarus/components/sqldb or the corresponding directory under OS X or Windows and choose the sqldblaz.lpk file. If everything works out as planned you will see the Package Manager. The Package Manager is showing a treeview with the files in the package and the required packages. Now press Compile if you don't want to install the component into the IDE, otherwise you should press Install. Next we get a warning about Lazarus only supporting static linked libraries and the question if you want to rebuild Lazarus. Just press Yes and sit back. Lazarus will be rebuilt, and depending on your configuration restarted.

If everything went well you'll see a new tab called SQLdb. This tab will contain two components a TSQLConnection and a TSQLQuery. What we need next is a Connection component. Once again go to Components -> Open Package File and navigate to /usr/share/lazarus/components/sqldb/interbase. Open the ibconnectionlaz.lpk file and again press Compile and Install and Yes. :)

Next time Lazarus is started the SQLdb tab also contains a component TIBConnection.

in the meantime all supported components.

Anything else?

Well that is all there is to it. You're now set to make your first program connecting to an Interbase server. See this sources to download a small example. If you have any questions, go to the lazarus forum or post it to the lazarus mailing list.

Compile an IDE with packages at command line

There is no command line tool yet, to configure and setup the IDE config files to add/remove packages. You must setup this with an IDE, copy the configs and adapt the path. See here for details: Install IDE packages without the IDE. But the rest can be done on command line:

First build a normal IDE and LCL

 make clean all

Then compile the IDE with packages

This will build the packages to be installed, then the IDE and finally link all together:

lazbuild --build-ide=

The --build-ide parameter can take some options, for example -gh for heaptrc or '-gh -gt'.

See also