IBM U2
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| Developer(s) | IBM |
|---|---|
| Stable release | UniData 7.2, UniVerse 10.2 |
| Operating system | Cross-platform |
| Type | MultiValue Database |
| License | Proprietary |
| Website | http://www.ibm.com/ |
IBM U2 is a family of database management software (DBMS) marketed by IBM. It includes two MultiValue database platforms: IBM UniData and IBM UniVerse.[1] Both products are operating environments that run on the major Unix and Linux systems and on Windows NT/2000.[2][3] They are both derivatives of the Pick operating system.[4][citation needed] The family also includes developer and web-enabling technologies such as IBM SystemBuilder, RedBack, and wIntegrate.[1]
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[edit] History
UniVerse was originally developed by Vmark Systems for vertical application development. UniData was originally developed by the UniData Corporation for embedding in vertical software applications. In 1997, the UniData Corporation merged with Vmark Systems to form Ardent Software.[5] In March of 2000, Ardent Software was acquired by Informix.[5] IBM subsequently acquired the database division of Informix in April 2001,[6] making UniVerse and UniData the two pieces of IBM's U2 product family.
[edit] System structure
[edit] Accounts
- Systems are made up of 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, file name, keyword, alias, script, and other pointers. Accounts can also contain a set of related files created by a user.
- A system may have one or multiple accounts.
[edit] Files
- Accounts are made up of files. Files are similar to tables in a traditional 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 up of two parts: a data file and a file dictionary (DICT). The data file contains records that store the actual data. The file dictionary contains the metadata used to describe the contents of the file.
[edit] Hashed files
- For hashed files, a U2 system uses a hashing algorithm to sort the file's records into groups based on the record IDs. The algorithm then stores the address of each group in a hash table. When searching for data in a hashed file, the system only searches the group where the record ID is stored, making the search process run more efficiently and more quickly than searching through the whole file.
[edit] Nonhashed files
- Nonhashed files are used to store data with little or no logical structure such as program source code or plain text. This type of file is stored as a subdirectory within the account directory on the host operating system.
[edit] Records
- Files are made up of records, which are similar to rows within tables of a traditional relational database. Each record has a unique key (called a "record ID" in U2) 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 the following string:
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- 123-45-6789^JOHN JONES^jjones@company.com^432100^...
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- might represent a record in the EMPLOYEE file with 123-45-6789 as the Record ID, JOHN JONES as the first field, jjones@company.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 take up 49 bytes of storage. Also notice that a given value only takes up as many bytes as are necessary. For example, in another record of the same file, JOHN JONES (10 bytes) might be replaced by MARJORIE Q. HUMPERDINK (21 bytes) yet each name only consumes as much storage as it requires (plus one for the field mark).
- Fields may be broken down into values and even sub-values. Values are separated by value marks (character xFD); sub-values are separated by subvalue marks (character xFC). Thus, if John Jones happened to get a secord email address, the record might be updated to:
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- 123-45-6789^JOHN JONES^jjones@company.com]johnnyjones@aol.com^432100^...
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- 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.
[edit] 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.
[edit] Programmability
Both UniVerse and UniData have a BASIC language (UniVerse Basic and UniBasic, respectively) similar to Pick/BASIC which naturally operates on the structures of the MultiValue database.
IBM provide a set of Client Tools to allow software developers to access U2 databases from other software languages. [7]
IBM Client Tool interfaces include:
- ODBC / JDBC
- UniOLEDB - OLEDB Driver
- UniObjects (COM)
- UniObjects (.NET)
- UniObjects (Java)
- Native XML
- U2 Web Services
[edit] Professional Certification
IBM offers seven professional certification designations related to the U2 product family.[8] All carry the title IBM Certified Solutions Expert.
- U2 Family Application Development
- U2 UniData V5.2 Administrator
- U2 UniData V6.1 Administration
- U2 UniData V7.1 Administration
- U2 UniVerse V9.6 Administration
- U2 UniVerse V10.1 Administration
- U2 UniVerse V10.2 Administration
[edit] User Group & Other Third Party Support
There is a recognized international user group, the U2UG
There are two magazines which cover the market with business and technical information: International Spectrum and Database Trends and Applications.
[edit] Notes
- ^ a b 'U2 Product Family', IBM Corporation
- ^ 'U2 Product Family - U2 Library', IBM Corporation
- ^ 'UniVerse System Description, Version 10.2' page 1-3, IBM Corporation
- ^ 'UniVerse Guide for Pick Users, Version 10.2' page 1-3, IBM Corporation
- ^ a b 'Ardent Definition', PC Magazine
- ^ 'Informix Definition' PC Magazine
- ^ 'IBM Client Tools', IBM Corporation
- ^ 'IBM Information Management - Product Certifications', IBM Corporation
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