Differences from the Anchor Modeling and an Entity Relationship Database

International Journal of Advanced Research in Computer Engineering & Technology (IJARCET) Volume 7, Issue 8, August 2018, ISSN: 2278 – 1323

Differences from the anchor modelingand an entity relationship database

Nguyễn Thị Thùy Trang

 independent way and proposes a naming convention, Section Abstract—Challenges have been facing to when designing 3 introduces a brief comparison between entity relationship database nowadays is that traditional model cannot adapt to modeling and anchor database (relying on Anchor modeling), store, maintain and evolve data warehouse that is a complex, Section 4 concludes the article and suggests directions for error prone, and time consuming activity. Thus, data models of further research. warehouse have to be modular, flexible, and track changes in the handled information. The concept of Anchor modeling is Highlight a section that you want to designate with a aimed to solve the above problems with many essential benefits. certain style, and then select the appropriate name on the style Anchor modeling is a temporal database modeling technique menu. The style will adjust your fonts and line spacing. Do which allows designers to model large systems needed to record not change the font sizes or line spacing to squeeze more the history of data. With anchor modeling, its information or text into a limited number of pages. Use italics for data is under evolution as well as the automatic generation of emphasis; do not underline. corresponding database implementations. This approach helps to solve the restrictions of recording pieces of historical data of other information systems modeling methods. Currently, most of databases over the world are developed by II. ANCHOR DATABASE AND ITS ADVANTAGES entity_relationship model. While companies, business, schools, Anchor Modeling [2] is a graphical data modeling bank… want to store the historical data and how to convert their entity relationship database to anchor modeling quickly, technique with a number of modeling patterns that are safely and costly. In this paper, from the theory of anchor embodied in a set of novel constructs capturing aspects such modeling, we will compare the differences between anchor as historization and fixed sets of entities. In addition, Anchor modeling with relational structure. Modeling [2]enables robust and flexible representation of changes in the form of extensions, which makes different Index Terms—anchor modeling, entity relational model; versions of a model continuously available as subsets of the latest model.Anchor Modeling provides effortless cross-version querying as well as brings a key benefit in data I. INTRODUCTION warehouse environments, as applications remain unaffected It is not denying the fact that an ER model becomes a by the evolution of the data model. Furthermore,it is possible popular model in the world. In software engineering, an to decompose data models into small, stable and manageable entity–relationship model (ER model) is a data model for components based on evolution through extensions (instead describing and managing the data or information of a of modifications). business domain or its process requirements. There are a lot There are many evolutions in anchor modeling [3]. Firstly, of software developers that choose this model in order to anchor modeling provides full support both 6NF and time of design and manage their database. However, this model change. The designers can store a body of information under exists many negative issues such as can not able to evolution and allow historical searches over it. Thus, anchor non-destructively evolve the model, allowing to null values, modeling can be known as a temporal database. Then, the and do not keep the information free from redundancies are structure in Anchor modeling experiences many changes. gained. Thus, it is necessary to replace a new model that aims Next, changing constrains in Anchor modeling has minimal to solve the advantages of ER model. support (there are only primary and foreign key). Besides, Anchor modeling was created in order to avoid its evolution in anchor modeling is that changing interpretation drawbacks and take the advantage of the benefits from a high and changing origins. Finally, the restricted support results to degree of normalization. Anchor model that is applied in changer reliability in anchor modeling. many countries is aimed to solve record the history of data. Anchor modeling has four basic modeling concepts: Anchor modeling [1] can both evolve information that is anchors, attributes, ties, and knots that will represent detail in implementable in current relational databases and combines section A normalization and emulation to provide an agile database A. The basis notions of Anchor Modeling modeling technique. The article is organized as follows. Section 2 defines the 1) Anchors - entities basic notions of Anchor Modeling in a technology An anchor represents a set of entities, such as a set of actors or events. Name of anchors [1] consists of two letter mnemonic and descriptor and it is unique in the model.

Nguyen ThiThuyTrang, Danang University of Technology and Education, Danang, Vietnam

International Journal of Advanced Research in Computer Engineering & Technology (IJARCET) Volume 7, Issue 8, August 2018, ISSN: 2278 – 1323

a) A knotted static tie is used if the instances of a relationship belong to certain categories, otherwise use a static tie. b) A knotted historized tie is used if a instances of a relationship belong to certain categories and the relationship may change over time.

Fig. 1. Example of Anchor

2) Knots – shared properties A knot represents a fixed, typically small, set of entities that do not change over time. While anchors are used to represent arbitrary entities, knots are used to manage properties that are shared by many instances of some anchor. Fig. 4. Example of Tie Name of knots [2] is based on three letter mnemonic and descriptor and it is also unique on the anchor. B. Benefits of Anchor Modeling Anchor modeling is open source database modeling technique that has many benefits [2]. This modeling can handle evolving information easily that based on keeping the integrity intact. Moreover, the lifetime of databases improves significantly and databases can exit with long life expectancy. Besides, with simplified modeling concepts, Fig. 2. Example of Knot anchor modeling is hard to make mistakes with and less prone to error. This model enables modular and iterative 3) Attributes - properties development as well as no need translation logic to the Attributes are used to represent properties of anchors. physical layer. Other advantages of anchor modeling are that Name of attribute [2] includes inherited anchor mnemonic, it automates the generation of SQL scripts and no downtime three letter mnemonic, inherited anchor descriptor, and when upgrading databases. Finally, anchor modeling can descriptor. There are four kinds of attributes: static, scan only relevant data during searches and sparse data cause historized, knotted static and knotted histories [1]. no gaps (no null value). [1]represents the essential benefits of a) Static attribute: properties of entities (anchors), anchor modeling by categorizing and listing details in Table where it is not needed to keep the history of changes to the attribute I. values b) A historized attribute is used when changes of the TABLE I. ESSENTIAL BENEFITS OF ANCHOR MODELING attribute values need to record. This means that a historized attribute is used if versioning of attribute values are of importance, Ease of Expressive - Using a small otherwise use a static attribute modeling concepts and number of c) A knotted static attribute is used to represent notation expressive relationships between anchors and knots. It can explain another concepts and definition that a knotted static attribute is used if attribute values modeling represent categories or can take on only a fixed small set of values, guidelines in order otherwise use a static attribute, to decrease the d) A knotted historized attribute is used when the number of options relationship with a knot value is not stable but may change over time. Its another definition is that a knotted historized attribute is available and the used if attribute values represent categories or a fixed small set of risk of introducing values and the versioning of these are of importance. errors in an anchor model Historization - It is simple to by design manage different versions of information in the form of historized attributes and ties - Allowing Fig. 3. Example of Attribute Agile development independent work 4) Ties - relationships on small subsets of Ties represent an association between two or more anchor the model under entities and optional knot entities. Name of ties [2] is based consideration and on inherited anchor and knot mnemonics separated by the later can be roles they play in the relationship. Tie has four kinds [2]: integrated into a static, historized, knotted static and knotted historized tiers. A global model. historized tie is used if a relationship may change over time, - Do not affect otherwise use a static tie the existing parts

of a model if there Less index - Most index is a changing space needed clustered and only requirements rearrange the which i handled by actual data additions - Tables are Reusability - Having a high narrow and automation degree of structure relied on the small number of III. THE COMPARATION BETWEEN ER MODEL AND modeling that ANCHOR MODEL constructs together There are many differences between Anchor Modeling and with the naming ER modeling. Their difference is represented in table II [4] conventions Simplified Ease of - Enabling to TABLE II. COMPARISON BETWEEN ER MODEL AND ANCHOR MODEL Database attribute facilitate tracing ER Model Anchor Modeling Maintenance changes attribute changes Single positor Multiple positors directly because Only certain statements Reliability ranging data is historized from being certain of a on an attribute statement to its level rather than opposite row level No history of versions Complete history of Absence of - Do not exits No history of versions and null values null values in order corrections corrections to save storage space In particularly, entities in a relational database which is Simple index - Representing database tables can become an anchor or knots. A knot design attribute, anchor represents an attribute with constant value or attribute with a and knot tables for small range value. Thus, entities which have one primary key the clustered and have two attributes (2 columns) can be knots. Besides, indexes entities consist of strong and weak entities; strong entities - Do not analysis will be the anchor in anchor modeling; weak ones which of what columns to depend on two tables will be the anchor with the tie index connected to its related tables; tables formed by many Update-free - Data can be relationships will be a tie, if it hasn’t attribute except of asynchrony handled in a simple primary key and/or foreign key. If it has other attributes then way such as adding it will be an anchor [5]. In anchor modeling, static attribute late arriving data represents attribute with a fixed value, no change by time, and storing data for while attributes that value is increasing or decreasing or a single attribute in change regularly are grouped into historized attributes. a table of its owns Finally, relationships between entities among anchors will be High High run-time - Achieving a ties. performance performance much better TABLE III. THE TRANSFORMATION FROM RELATIONAL SCHEMA NOTIONS database performance for TO THE ANCHOR RELATIONAL SCHEMA many types of queries Efficient - Having small Relational database Anchor Database storage size than less 1.Entities have one primary normalized key and only have 2 attributes Knots (Domain) database because (2 columns) of the absence of 2. Entities apart from the null values Anchors entities in (1) Parallelized - It is possible to 3. Relationships between physical media parallelize Ties entities in (2) access physical media ace 4. Attributes can store time based on the high Histories Attributes degree (value change regularly) 5. Attributes can not store decomposition and Static Attributes table elimination time (with a fixed value) when using views and functions

International Journal of Advanced Research in Computer Engineering & Technology (IJARCET) Volume 7, Issue 8, August 2018, ISSN: 2278 – 1323

IV. CONCLUSION

From the advantages of Anchor modeling and requirement of converting the ER model to Anchor modeling, the author will focus on researching appreciate algorithm aimed to build a tool that can convert entity relationship database to Anchor database. This tool can solve some issue such as generating automatically design and coping whole data from entity relationship database to Anchor modeling

REFERENCES

[1] Lars Rönnbäck, "Anchor Modeling - A technique for information underevolution", 2011. [2] L. R¨onnb¨ack, O. Regardt, M. Bergholtz, P. Johannesson, and P. Wohed, "Anchor Modeling - agile information modeling in evolving data environment," 2010. [3] Lars Rönnbäck, "Anchor modeling (with temporal data)", 2012 [4] Lars Rönnbäck, "Anchor modeling - Introduction", 2015. [5] HumasakSimanjuntak, Marcella Tambunan, KamaruddinManullang, Hanna Panjaitan,“An Automatic tool for Anchor Model Data warehouse Development”, InternetWorking Indonesia Journal, Vol.8, No.2, 2016 [6] http://www.anchormodeling.com/modeler/latest/