System structure
Accounts
Systems are made of one or more accounts. Accounts are directories stored on the host operating system that initially contain the set of files needed for the system to function properly. This includes the system's VOC (vocabulary) file that contains every command, filename, keyword, alias, script, and other pointers. Each of these classes of VOC entries can also be created by a user.
Files
Files are similar to tables in a relational database in that each file has a unique name to distinguish it from other files and zero to multiple unique records that are logically related to each other.
Files are made of two parts: a data file and a file dictionary (DICT). The data file contains records that store the actual data. The file dictionary may contain metadata to describe the contents or to output the contents of a file.
Hashed files
For hashed files, a U2 system uses a hashing algorithm to allocate the file's records into groups based on the record IDs. When searching for data in a hashed file, the system only searches the group where the record ID is stored, making the search process more efficient and quicker than searching through the whole file.
Nonhashed files
Nonhashed files are used to store data with little or no logical structure such as program source code, XML or plain text. This type of file is stored as a subdirectory within the account directory on the host operating system and may be read or edited using appropriate tools.
Records
Files are made of records, which are similar to rows within tables of a relational database. Each record has a unique key (called a "record ID") to distinguish it from other records in the file. These record IDs are typically hashed so that data can be retrieved quickly and efficiently.
Records (including record IDs) store the actual data as pure ASCII strings; there is no binary data stored in U2. For example, the hardware representation of a floating-point number would be converted to its ASCII equivalent before being stored. Usually these records are divided into fields (which are sometimes called "attributes" in U2). Each field is separated by a "field mark" (hexadecimal character FE).
Thus this string:
123-45-6789^JOHN JONES^jjones@example.com^432100^...
might represent a record in the EMPLOYEE file with 123-45-6789 as the Record ID, JOHN JONES as the first field, jjones@example.com as the second field and $4321.00 as a monthly salary stored in the third field. (The up-arrow (^) above is the standard Pick notation of a field mark; that is, xFE).
Thus the first three fields of this record, including the record ID and trailing field mark, would use 49 bytes of storage. A given value uses only as many bytes as needed. For example, in another record of the same file, JOHN JONES (10 bytes) may be replaced by MARJORIE Q. HUMPERDINK (21 bytes) yet each name uses only as much storage as it needs, plus one for the field mark.
Fields may be broken down into values and even subvalues. Values are separated by value marks (character xFD); subvalues are separated by subvalue marks (character xFC). Thus, if John Jones happened to get a second email address, the record may be updated to:
123-45-6789^JOHN JONES^jjones@example.com]johnnyjones@example.net^432100^...
where the close bracket (]) represents a value mark.
Since each email address can be the ID of a record in separate file (in SQL terms, an outer join; in U2 terms, a "translate"), this provides the reason why U2 may be classified as a MultiValued database.
Data
Raw information is called Data. A record is a set of logical grouped data. e.g. an employee record will have data stored in the form of fields/attributes like his name, address etc.
A relational database is a database based on the relational model of data, as proposed by E. F. Codd in 1970. A system used to maintain relational databases is a relational database management system (RDBMS). Many relational database systems are equipped with the option of using SQL for querying and updating the database.
Informix is a product family within IBM's Information Management division that is centered on several relational database management system (RDBMS) and multi-model database offerings. The Informix products were originally developed by Informix Corporation, whose Informix Software subsidiary was acquired by IBM in 2001.
Ingres Database is a proprietary SQL relational database management system intended to support large commercial and government applications.
Db2 is a family of data management products, including database servers, developed by IBM. It initially supported the relational model, but was extended to support object–relational features and non-relational structures like JSON and XML. The brand name was originally styled as DB/2, then DB2 until 2017 and finally changed to its present form.
Informix-4GL is a 4GL programming language developed by Informix during the mid-1980s. At the time of its initial release in 1986, supported platforms included Microsoft Xenix, DEC Ultrix, Altos 2086, AT&T 3B2, AT&T 3B5, AT&T 3B20 and AT&T Unix PC.
FileMaker is a cross-platform relational database application developed by Claris International, a subsidiary of Apple Inc. It integrates a database engine with a graphical user interface (GUI) and security features, allowing users to visually modify a database. Versions for desktops, servers, iOS and web-delivery have been released.
Adabas, a contraction of “adaptable database system," is a database package that was developed by Software AG to run on IBM mainframes. It was launched in 1971 as a non-relational database. As of 2019, Adabas is marketed for use on a wider range of platforms, including Linux, Unix, and Windows.
The Pick Operating System, also known as the Pick System or simply Pick, is a demand-paged, multi-user, virtual memory, time-sharing computer operating system based around a MultiValue database. Pick is used primarily for business data processing. It is named after one of its developers, Dick Pick.
Comma-separated values (CSV) is a text file format that uses commas to separate values. A CSV file stores tabular data in plain text, where each line of the file typically represents one data record. Each record consists of the same number of fields, and these are separated by commas in the CSV file. If the field delimiter itself may appear within a field, fields can be surrounded with quotation marks.
The Integrated Database Management System (IDMS) is a network model (CODASYL) database management system for mainframes. It was first developed at B.F. Goodrich and later marketed by Cullinane Database Systems. Since 1989 the product has been owned by Computer Associates, who renamed it Advantage CA-IDMS and later simply to CA IDMS. In 2018 Broadcom acquired CA Technologies, renaming it back to IDMS.
The following tables compare general and technical information for a number of relational database management systems. Please see the individual products' articles for further information. Unless otherwise specified in footnotes, comparisons are based on the stable versions without any add-ons, extensions or external programs.
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IBM InfoSphere DataStage is an ETL tool and part of the IBM Information Platforms Solutions suite and IBM InfoSphere. It uses a graphical notation to construct data integration solutions and is available in various versions such as the Server Edition, the Enterprise Edition, and the MVS Edition. It uses a client-server architecture. The servers can be deployed in both Unix as well as Windows.
Microsoft Identity Integration Server (MIIS) is an identity management (IdM) product offered by Microsoft. It is a service that aggregates identity-related information from multiple data-sources. The goal of MIIS is to provide organizations with a unified view of a user's/resources identity across the heterogeneous enterprise and provide methods to automate routine tasks.
A MultiValue database is a type of NoSQL and multidimensional database, typically considered synonymous with PICK, a database originally developed as the Pick operating system.
SB/XA is a 4GL development and runtime environment originally written for the Pick family of computer databases/environments and now part of the Rocket U2 software suite.
IBM Data magazine is a U.S.-based custom, online magazine published by TDA Group for IBM Corp. With a worldwide readership of more than 100,000, the magazine provides how-to information about Db2, Informix, UniVerse, and UniData, along with coverage of related tools, software, and solutions.
An embedded database system is a database management system (DBMS) which is tightly integrated with an application software; it is embedded in the application. It is a broad technology category that includes:
Informix Corporation was a software company located in Menlo Park, California. It was a developer of relational database software for computers using the Unix, Microsoft Windows, and Apple Macintosh operating systems.
Distributed Data Management Architecture (DDM) is IBM's open, published software architecture for creating, managing and accessing data on a remote computer. DDM was initially designed to support record-oriented files; it was extended to support hierarchical directories, stream-oriented files, queues, and system command processing; it was further extended to be the base of IBM's Distributed Relational Database Architecture (DRDA); and finally, it was extended to support data description and conversion. Defined in the period from 1980 to 1993, DDM specifies necessary components, messages, and protocols, all based on the principles of object-orientation. DDM is not, in itself, a piece of software; the implementation of DDM takes the form of client and server products. As an open architecture, products can implement subsets of DDM architecture and products can extend DDM to meet additional requirements. Taken together, DDM products implement a distributed file system.
