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DeepDive Application's Structure and Operations |
A DeepDive application is a directory that contains the following files and directories:
This file can be thought as the blueprint of a DeepDive application. DDlog declarations and rules written in this file tell DeepDive:
- What each relation looks like and how one is derived from others.
- What user-defined functions are there, what input/output schema they expect, and their implementation details.
- What random variables are to be modeled, how they are correlated.
Extra configuration not expressed in the DDlog program is in this file. Extractors, and inference rules can also be written in HOCON syntax in this file, although DDlog is the recommended way. See the Configuration Reference for full details.
A URL representing the database configuration is supposed to be stored in this file.
Environment variable $DEEPDIVE_DB_URL overrides the URL stored this file.
For example, the following URL can be the line stored in it:
postgresql://user:password@localhost:5432/database_name
SSL connections for PostgreSQL can be enabled by setting parameter ssl as true in the URL, e.g.:
postgresql://user:password@localhost:5432/database_name?ssl=true
If you use a self-signed certificate, you may want to disable validation with an extra sslfactory parameter:
postgresql://user:password@localhost:5432/database_name?ssl=true&sslfactory=org.postgresql.ssl.NonValidatingFactory
Any data to be processed by this application is suggested to be kept under this directory.
Any user-defined function (UDF) code is suggested to be kept under this directory. They can be referenced from deepdive.conf with path names relative to the application root.
Each run/execution of the DeepDive application has a corresponding subdirectory under this directory whose name contains the timestamp when the run was started, e.g., run/20150618/223344.567890/.
All output and log files that belong to the run are kept under that subdirectory.
There are a few symbolic links with mnemonic names to the most recently started run (run/LATEST), last successful run (run/FINISHED), last failed run (run/ABORTED) for handy access.
Data-Definition Language (DDL) statements for setting up the underlying database tables should be kept in this file. This may be omitted when the application is written in DDlog.
In addition to the data files, there should be an executable script that knows how to load the data here to the database once its tables are created.