Each Recital table can have one or more data dictionaries to provide a central repository for constraints and other metadata.
Here's how to set up field validation for a field with a small static number of acceptable values.
Using the example.dbf table from the southwind sample database, validation can be added to the title field to ensure it matches one of a list values.
If you have access to the Recital Workbench, you can use the modify structure worksurface to add and alter your dictionary entries, including a customized error message if required.
Here's how to set up field validation for a field with a small static number of acceptable values.
Using the example.dbf table from the southwind sample database, validation can be added to the title field to ensure it matches one of a list values.
open database southwindThe inlist() function checks whether the specified expression exists in the comma-separated list which follows. An attempt to update title with a value not in the list will give an error: Validation on field 'TITLE' failed.
alter table example add constraint;
(title set check inlist(alltrim(title),"Miss","Mr","Mrs","Ms"))
If you have access to the Recital Workbench, you can use the modify structure worksurface to add and alter your dictionary entries, including a customized error message if required.
- For building shared libraries on the MAC the following need to be set
-
- The shared library file extension should be .dylib
- The compile flag is -dynamic
- For accessing the shared libraries at runtime
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- DYLD_LIBRARY_PATH needs to be set to the location of the shared libraries
- Useful utilities for shared library support
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- The following command will display the table of contents of the dynamically linked library
otool -TV sharedlibraryfile.dylib
There is a good article here this describes agile software development techniques. This is what we have always been doing but it's nice to see it defined formally.
We use this technique ourselves on our development portal.
Recital 10.0 introduced the COPY DATABASE <name> TO <name> command.. The full syntax is;
COPY DATABASE <name> TO <name> [ IF [ NOT ] EXISTS ]This command is used to copy an existing database to a new database. By default an error will be returned if the target database already exists. Specifying the optional IF NOT EXISTS keywords no error will be returned if the target database already exists. If the optional IF EXISTS keywords are specified and the target database already exists, then it will be removed before the copy. Both the databases must be closed before they can be copied.
Opening SSH to the outside world is a security risk. Here is how to restrict SSH access to certain IP addresses on a machine.
- Edit the /etc/hosts.allow file to include these lines, assuming your machine is on the 192.168.2.x nonrouting IP block, and you want to enable an external address of 217.40.111.121 IP block: Remember to add the period on the end of each incomplete IP number. If you have another complete IP address or range, add a space and that range on the end.
sshd,sshdfwd-X11: 192.168.2. 217.40.111.121
- Edit your /etc/hosts.deny file to include this line:
sshd,sshdfwd-X11:ALL
- These lines refuse SSH connections from anyone not in the IP address blocks listed.
Additionally you can restrict SSH access by username.
- Edit the /etc/ssh/sshd_config file and add the following lines
PermitRootLogin no
AllowUsers user1 user2 user3 etc
PasswordAuthentication yes
Now restart the ssh daemon for these changes to take effect
service sshd restart
Key features of the Recital database include:
- SQL-92 and a broad subset of ANSI SQL 99, as well as extensions
- Cross-platform support
- Stored procedures
- Triggers
- Cursors
- Updatable Views
- System Tables
- Query caching
- High-performance
- Single-User and Multi-User
- Multi-Process
- ACID Transactions
- Referential Integrity
- Cascading Updates and Deletes
- Multi-table Joins
- Row-level Locking
- BLOBs (Binary Large Objects)
- UDFs (User Defined Functions)
- OLTP (On-Line Transaction Processing)
- Drivers for ODBC, JDBC, and .NET
- Sub-SELECTs (i.e. nested SELECTs)
- Embedded database library
- Database timelines providing data undo functionality
- Fault tolerant clustering support
- Hot backup
Recital 10 introduced the REQUIRE() and REQUIRE_ONCE() statement.
The REQUIRE() statement includes and executes the contents of the specified file at the current program execution level.
When a file is included, the code it contains inherits the variable scope of the line on which the include occurs. Any variables, procedures, functions or classes declared in the included file will be available at the current program execution level.
The REQUIRE_ONCE() statement is identical to the REQUIRE() statement except that Recital will check to see if the file as already been included and if so ignore the command.
The full syntax is:
The REQUIRE() statement includes and executes the contents of the specified file at the current program execution level.
When a file is included, the code it contains inherits the variable scope of the line on which the include occurs. Any variables, procedures, functions or classes declared in the included file will be available at the current program execution level.
The REQUIRE_ONCE() statement is identical to the REQUIRE() statement except that Recital will check to see if the file as already been included and if so ignore the command.
The full syntax is:
REQUIRE( expC ) REQUIRE_ONCE( expC ) e.g. REQUIRE_ONCE( "myapp/myglobals.prg" )
Recital 10 introduced the PIPETOSTR() function. This function operates in a similar fashion to the FILETOSTR() function but it can be used to capture the output from externally executed operating system commands. e.g.
// determine how many Recital users are on the system
nusers = pipetostr("ps -ef | grep db.exe | wc -l")
When using Recital on linux you can integrate your favorite linux shell commands and use then directly inside Recital using the alias command. This can be particularly useful when you ssh into a remote system and run recital. You can then issue linux commands without having to open another terminal session. Several aliased shell commands are predefined in /opt/recital/conf/config.db. You can add others to suit your needs.
On my system i have these commands aliased.
The alias command handles parameter substitition.
alias pwd "? default()"
alias cp "copy file "
alias mv "rename "
alias rm "erase "
alias ls "run('ls $0')"
alias ps "run('ps $0')"
alias grep "run('grep $0')"
alias cd "set default to $1"
alias cls "clear screen"
These commands can now be used inside the Recital command window just as you would use them at the linux prompt, including the ability to pipe commands together.
ls -l | grep .prg ps -elf | grep db.exeThe run() function that is used to run the shell command as specified in the alias command will capture output and display it in a text viewer. If you want to run the command and display the contents full screen, then specify true as the third parameter to the run().
run("command", true, true)
The arguments to run() are as follows.
| Argument | Description |
|---|---|
| 1 | the command line to run |
| 2 | True if output should be displayed in a text area (default True) |
| 3 | True if the output should be displayed full screen (default False) |
| Macro | Description |
|---|---|
| $0 | the command line following the command name |
| $1..$n | the arguments given to the command |