Principles for conversion

• You must have an "interpreted" version of the database (xxxx.4DB file for the structure), as well as the Designer password to perform a conversion;

• Make a copy of your database before conversion;

• Perform a syntax check. Even if you do not want to compile your database, this check can help warn you about possible errors;

• Use the Maintenance and Security Center to check and repair the structure and data;

• Check whether you have any PICTs using the GET PICTURE FORMATS command (or the 4D Pack _o_AP Is Picture Deprecated command) and convert them using the CONVERT PICTURE command (in 4D v14, there is still the possibility of using QuickTime in 32-bit versions by means of a selector for the SET DATABASE PARAMETER command);

• (Optional) Possible to implement primary keys if data journaling is needed (starting with version 14) (see Primary keys in the Design Reference manual).

• Since version 13.5, it is mandatory for Unique fields to be indexed. You will no longer be allowed to create/modify any records for a non-indexed Unique field: attempting to save the record will generate an error (-9998 Unique record exists, 1088 Index is invalid or missing). To create missing indexes, or generate a disk file listing all the non-indexed fields, refer to the Appendix: Useful methods for conversion of the "Conversion to 4D v15" document.

Databases created with version 15 of 4D or 4D Server (as well as ones created in v11, v12, v13 and v14) are compatible with 4D version 16 (structure and data files). You can convert any interpreted structure file. To do this, just launch 4D v16 and open your structure file (xxx.4DB file) in interpreted mode.

A dialog warns you that the structure and data files are going to be converted:

After your structure file is converted to 4D v16, it can no longer be opened using a former version.

Data files are not converted for databases in 4D v15 or 4D v15 Rx. However, they are converted for databases in 4D v14 and earlier versions. In this case, a second dialog box is displayed:

This data file is also converted to version 16 but it can still be opened and used with 4D v14.4 and higher or 4D v15 (4D v14 R5).

Use the Maintenance and Security Center (MSC) again to check and repair the structure and data.

As a reminder, on the structure:

• orphan methods (__Orphan__xxxxx) are indicated by warnings in the log file of the MSC and can be deleted using the Explorer (after checking that their code is no longer useful);
• forms cannot contain duplicate object names: they are signaled by warnings in the log file of the MSC. You can perform a repair operation on the database in order to modify these names (in this case, make sure you check the programming of object names).

New feature concerning the structure:

• Detection of pictures in the structure that contain a PICT format. See Verifying the application in the MSC chapter.

New features concerning the data: detection of duplicates in Unique fields. Additional information is provided:

• When using the MSC or a command such as VERIFY DATA FILE, the log files generated now include the names of the tables and fields concerned, as well as each duplicate value.
  Note: When entering data, the "Duplicate key" error dialog box now includes the names of the tables and fields concerned, as well as the dpulicate value, and the GET LAST ERROR STACK command also includes detailed information about any duplicates found.
  When 4D opens a data file, if it is necessary to build (or rebuild) an index, duplicates are now detected automatically in any associated field(s) which are declared unique. In this case, a specific alert dialog box is displayed before opening the database, providing the user with the information needed to identify and remove the duplicates:
  
  

During the upgrade to 4D v16 and because of the update of the Unicode library (ICU - International Components for Unicode), all text and keyword indexes in 4D were rebuilt. This oepration is performed automaticaly when the database is opened for the first time (warning: this operation may take a significant amount of time).

Similarly, when you re-open a v16 database with a 4D v15 R5 or earlier version, this automatically triggers the rebuilding of the text and keyword indexes.

Note: With 4D v16, we have significantly optimized the global reindexing algorithm for the data of the database. All its processes were reviewed and this operation can now be up to twice as fast. Global reindexing is required, for example, after repairing the database or when the .4dindx file has been deleted.