Accessing from isCOBOL

isCOBOL uses the c-tree interface in one of the following cases:

1.	when the runtime framework property iscobol.file.index is set either to "ctreej"; or

2.	when the runtime framework property iscobol.file.index.FileName is set either to "ctreej"; or

3.	when CLASS "faircom.rtg.DynamicCtreeJ" is specified in the SELECT Clause.

The isCOBOL Framework becomes a client process that connects to a listening c-tree Server. To provide this connection, isCOBOL loads the ctree client library (ctree.dll on Windows, libctree.so on Linux) which must be available in the library path and must be the same version of the listening c-tree Server.

isCOBOL can create c-tree files directly into the c-tree SQL Server so they are available as database tables for external SQL tools. Consult Creating c-tree files into SQL Server from the COBOL Program chapter for details.

In order to bring existing c-tree files into the SQL Server, instead, ctutil utility must be used. Consult Registering existing c-tree files in c-tree SQL Server chapter for details.

Accessing through a File Connector

The c-tree File Connector allows to work on c-tree files managed by c-tree by separating ISAM native access from java process. This solution is suggested when working with third party application servers (e.g. Apache Tomcat).

isCOBOL uses the file connector interface in one of the following cases:

1.	when the runtime framework property iscobol.file.index is set either to "fscsc"; or

2.	when the runtime framework property iscobol.file.index.FileName is set either to "fscsc"; or

3.	when CLASS "com.iscobol.io.DynamicConnector" is specified in the SELECT Clause.

Accessing to previous c-tree versions

If you need to interface with a previous c-tree version, you can’t rely on the c-tree client library installed along with isCOBOL. You need to replace it with the proper c-tree library taken from the distribution of the c-tree that you wish to interface.

In addition, the file handler class and its alias may be different. The following table lists the file handlers available for the various c-tree versions:

c-tree version	available file handlers
	values for iscobol.file.index	classes usable in FILE-CONTROL
9.5.51961 or previous	• ctree	• com.iscobol.io.DynamicCtree
between 9.5.53702 and 10.4.0.39110	• ctree2 • fscsc	• com.iscobol.io.DynamicCtree2 • com.iscobol.io.DynamicConnector
10.4.0.39701 or later	• ctreej [A] • ctree2 [B] • fscsc	• faircom.rtg.DynamicCtreeJ [A] • com.iscobol.io.DynamicCtree2 [B] • com.iscobol.io.DynamicConnector

[A] Supported since isCOBOL 2016 R1.

[B] Deprecated since isCOBOL 2016 R1.