Introduction

Jinx is an interactive tool for manipulating simple databases.

A Jinx-database consists of an arbitrary number of records. A record consists of fields. A field may contain arbitrary ASCII printable data (no newlines or tabs). All records in a single database have the same number of fields. A database may therefore be viewed as a row of columns. Associated with each column is a unique name (the fieldname). There is no limit on the number of columns in a Jinx-database. In a picture:

Associated with each column is a regular expression which is used as a constraint on the data that may be entered in the column. Users may override constraints when entering or modifying data.

With Jinx you can manipulate at most one database at a time. This database is called the current database. Jinx enables the user to

• define a new database by adding fields to an existing or empty database.
• open a database on disk to make that database the current one. The current database is a copy of the database on disk.
• look at the raw data in the current database and move around in it by specifying a search pattern, setting a record number or paging back and forth.
• inspect the current database at record-level. Records can be modified, added, copied and deleted. You can move around by searching for a specified pattern in the data etc.
• create a new database by selecting certain columns from the current database. This is called projection.
• create a new database by selecting records from the current database by specifying regular expressions for one or more fields. Any record with a field matching the given expression for that field is selected. This is called extraction.
• create a new database by joining the current database with another database.
• sort the current database.
• copy records in from another database.
• check the uniqueness of entire records or the combination of one or more fields.
• compute new values by specifying a Perl expression for one or more fields.
• write the current database to disk. This is called saving the database.

Jinx marks the current database as modified or not modified. A database is only marked not modified if it is an exact copy of a database on disk. After opening a database or saving one, the current database is marked not modified. Newly created databases are all marked modified initially. When the current database is marked modified and the user requests an action (like quiting Jinx, joining, projecting) that will scratch the current database, Jinx will ask permission first.

When on disk, a Jinx-database consists of two files: name.des containing the descriptor and name.dat containing the data (see section 5 for a description of their contents). Jinx uses name to identify a database. When opening a database a name has to be specified. That name becomes the name associated with the current database. Newly created databases are nameless. Changing the descriptor (fieldnames and/or patterns) will make the current database nameless. The user must specify a name when a nameless database is to be saved. That name becomes the name associated with the current database.
You can use Jinx by typing:

If a namelist is given, Jinx tries to open database name1. The other names are are presented as defaults when the opening of another database is requested. If no namelist is given, Jinx just starts up without a current database. With the L-option information is logged to the specified logfile. By default, Jinx will log activities like opening and saving of databases. Loglevel 1 or 2 are only there for debugging purposes and will log many activities related to the presentation.
The D-option will make Jinx dump core for undump-purposes. The v-option will show version and copyright information.

When in Jinx, you usually see the following things on the screen. At the top is information about the current database. At the bottom of the screen are a menu, the status line and a command line. The rest of the screen is used for presenting info in the database. The amount of info shown depends on the size of the screen.