Product New info in 4D Maintenance and security center MSC

New info available in MSC dialog

If you are using a huge database with a lot of data, you should be very familiar with the 4D MSC dialog. The Maintenance and Security Center contains all the tools needed for information, verification, analysis, maintenance, backup & compacting of data and structure files.

Based on recent feedback from some of our users, we have enhanced this dialog in three ways:

  • A link to the path of the log file has been added
  • New global information on the data is accessible
  • Information about tables are now available in both maintenance and standard modes
Product 4D Database: Search in array attribute

Search by linking array attribute query arguments

Object fields, introduced with 4D v15, allows to store and index unstructured data. This could be a common set of data, like first name, last name, birthday. It could be different data in each record, such as a shop that will need different attributes for shoes (size, color), computers (CPU, memory), printers (color, ink), a list of values or all in any combination.

Here is a real User Story from a 4D customer :

My badge application manages the access rights for each person to a building and for a time slot. This information is stored in a database as an array of objects ( e.g.: {access right, building, time slot} ). I want to be able to look for people who have access to a building during a time slot.”

4D provides several ways to query for data, using index and so extremely fast.

Product 4D Database: Sort records by object attribute

Sort records by object attribute

At each 4D release, object fields become more and more powerful.

A new 4D command for sorting your record selections according to one or more attributes is now available with 4D v16 R2. The new command ORDER BY ATTRIBUTE works the same as the command ORDER BY; you just have to pass an attribute path by which you want to order your selection – easy!


Detailed analysis of your database structure

Did you know that you can retrieve very detailed information on a table, field, indexes, relation or even on the complete database structure? This kind of information is always very useful for analysis or introspection purposes. Of course, you could use the 4D Pack deprecated commands: _AP Get field infos and _AP Get table info. Another option is to use the SQL system tables.

None of them allows you to retrieve all information. So why use a plug-in or SQL when you could use a 4D command? The EXPORT STRUCTURE command returns the complete database structure definition in an XML tree. This command exists since 4D v14 R4.


Take Control of the Cache Manager

4D v16 introduced a new fully optimized cache manager for the 64-bit product line. 4D v16 R2 is giving power to our advanced 4D developers to take control by themselves!

The cache manager internal algorithm is based on a priority concept associated to each object type to store in the cache memory. By default, the cache manager algorithm assigns a higher priority value for an index than for records. And recently used objects (records or indexes) have a higher priority to remain in the cache than objects that have not been used in the last two days, etc…


Boost your performance with the new cache manager

The 4D v16 version has definitely been designed for better performance and scalability. In addition to major features like preemptive multi-threading, 4D v16 64-bit is embedding a brand new cache manager for a optimized handling of objects in cache memory avoiding any fragmentation issues.

The new cache manager improves the usage of very large cache for modern computers (with 64 or even 128 GB of Cache) allowing to take advantage of low RAM prices to have even large databases fully in memory. It also improves the situation of small cache size with very large data files, by decreasing the amount of unloading memory with increased support of priorities for data objects to be hold or released from cache.


Go further with Object fields

Object fields introduced with v15 allows unstructured data bases, similar to schemaless database (NoSQL). 4D v16 goes a big step further. Get a dynamic structure for unstructured data… Confused?

Imagine you use an object field to allow your customers to store custom data, where they can create their own fields. This works well and is one of the most interesting reasons for using an object field. The problem is, how to allow your customer to query this unstructured data? You don’t know which ‘fields’ they used, you cannot build a query editor on top or offer a drop down with used values.


Database mirroring

When integrating the log file, 4D stops at the first error and doesn’t return any error message. Reasons for integration errors could be a damaged log, by example because of a bad hard disk or software error during writing. If that error happens at the end, no problem; but it could also be at the start or in the middle of the log. In this case, the data after the error might be useful.

Now, when the integration fails in standard mode, you can try integration in auto-repair mode. In this case, 4D tries to resolve the error encountered, doesn’t stop the integration, and returns the error list.


JSON export for Journal

In 4D applications, the data file is important, so all the activity of the database is stored in the log file. As you all know, the log file is a vital element for the restoration of your database following an unfortunate contingency. However all the information on the database activity may also be useful for analysis. For example, to check the activity on a table, to see the changes made by a user, and to follow a record’s history.