{"id":1409,"date":"2019-02-15T10:32:08","date_gmt":"2019-02-15T10:32:08","guid":{"rendered":"http:\/\/kusuaks7\/?p=1014"},"modified":"2023-07-14T11:51:12","modified_gmt":"2023-07-14T11:51:12","slug":"next-and-prior-pointing-in-data-models","status":"publish","type":"post","link":"https:\/\/www.experfy.com\/blog\/bigdata-cloud\/next-and-prior-pointing-in-data-models\/","title":{"rendered":"Next and Prior: Pointing in Data Models"},"content":{"rendered":"

Ready to learn Data Science? Browse\u00a0Data Science Training and Certification<\/a> courses developed by industry thought leaders and Experfy in Harvard Innovation Lab.<\/em><\/strong><\/p>\n

Pointers\u00a0have been in and out of data models. From the advent of the rotating disk drive in the 60s and until around 1990, pointers were all over the place (together with \u201chierarchies\u201d, which were early versions of aggregates of co-located data). But relational and SQL made them go away, only to reappear around year 2000 as parts of Graph Databases.<\/p>\n

Although summer is over, this post is easy going and comes around. Join me on a hopefully fascinating journey of the history of pointers in data models.<\/p>\n

Pointing at Things<\/strong><\/h4>\n

Pointing is a very basic gesture for humans.<\/p>\n

\"experfy-blog\"<\/a><\/p>\n

by\u00a0Hillebrand Steve<\/a>, U.S. Fish and Wildlife Service [Public domain], via Wikimedia Commons.<\/em><\/p>\n

Nobody is in doubt about what the intention is, regardless of culture, language and circumstance. Pointers are one of the strongest visualization tools in our possession. That is why I am so much in favor of directed graphs, as in e.g. concept maps and property graphs.<\/p>\n

Now I am pointing at pointers \u2013 over there, please!<\/p>\n

Episode 1: Pointer DMBS\u2019s<\/strong><\/h4>\n

One of the very first data stores was from IBM (in 1960). Its predecessor, which ran on magnetic tape, was called BOMP. It stands for Bill of Materials Processor. It was developed specifically for some large manufacturers, who needed to be able to do what later became materials requirements planning.<\/p>\n

Once BOMP was adapted for the new, revolutionary disk storage technology, it changed name to DBOMP, this time meaning \u201cDatabase Organization and Maintenance Processor\u201d! This happened in 1960. It was generalized somewhat and it does qualify as one of the first disk-based data stores.<\/p>\n

It was based on the concept of pointers which was the new very exciting possibility of rotating disks. Some added common sense was also added \u2013 the developers soon went away from raw disk addresses to schemes with blocks of data and index-numbers for rows on the block. Plus some free space administration. The blocks (and with them the data) could then be moved around on the disk. (In the beginning there was typically only one disk).<\/p>\n

Here is a greatly simplified bill of materials structure (tree) of a bicycle:<\/p>\n

\"experfy-blog\"<\/a><\/p>\n

Now, when you read and manipulate bills of materials, you need to:<\/p>\n