Assignment 5: Logical Design Part II
Assignment 5: Logical Design Part II
Introduce the concept of normalization in a letter to the executive and explain the pros and cons.
The main purpose of normalization is to reduce data redundancy and avoid inconsistent data. The benefits on normalizing a database would be to prevent the appearance of modification anomalies in the data. The anomalies can lead to the loss of needed data. Normalization would help with organizing your data to prevent redundancy. It would also establish and maintain the integrity of your data tables as well as eliminating inconsistent data dependencies. Each table should describe only one type of entity.
Normalization leads to separation of unrelated entities into separate entities: The pros for normalization: The fully normalized expression of a data model is very close to the most compact possible representation of data in terms of bytes per unit of information, which would help with performance A well-normalized database is faster to write and to access for the same reason which would also be a plus for performance. Normalization would cause relational inconsistencies which would mean no redundancy.
The cons for normalization: Normalization requires skill to provide functional views and access methods that are comprehensible and streamlined for consumer …show more content…
OLTP applications Normalization requires discipline to maintain conceptually current and normalized Normalization requires skill and discipline to keep well-indexed They can be difficult & expensive to do well.
Explain the problems associated with data redundancy as it pertains to effectively using information for reporting and analysis.
Data redundancy occurs in database systems which have a field that is repeated in two or more tables.
Data redundancy leads to data anomalies and corruption and generally should be avoided by design. Normalization would prevent redundancy and make the best possible usage of storage. By following the principles of normalization you can achieve a design that is highly flexible allowing the model to be extended when needed to account for new attributes, entity sets, and relationships. With normalization we can reduce redundancy, both to save space and to avoid inconsistencies in data which could affect information for reporting and
analysis.
Discuss your rationale for normalizing from your E-R Model and demonstrate:
The main reason to normalize a database is to prevent the appearance of modification anomalies in the data. Anomalies can lead to the loss of needed data or the introduction of spurious data. The process usually entails splitting two or more tables that together contain the same information. Each table in a fully normalized database deals with only one ideas.a. How you derived at your 3NF from the earlier assignment
An entity is in the first normal form if it contains no repeating groups. In relational terms, a table is in the first normal form if it contains no repeating columns. Repeating columns make your data less flexible, waste disk space, and make it more difficult to search for data. To convert to third normal form, remove attributes that depend on other descriptor key attributes.
b. The process you took in arriving at your 3NF
c. The three (3) step technique of transforming your data model into first normal form, second normal form, and third normal form
First Normal Form (1NF): Table must be two-dimensional, with rows and columns. Each row contains data that pertains to one thing or one portion of a thing. Each column contains data for a single attribute of the thing being described. Each cell (intersection of row and column) of the table must be single-valued. All entries in a column must be of the same kind. Each column must have a unique name. No two rows may be identical. The order of the columns and of the rows does not matter.
Second Normal Form (2NF): Table must be in first normal form (1NF). All nonkey attributes (columns) must be dependent on the entire key.
Third Normal Form (3NF): Table must be in second normal form (2NF). Table has no transitive dependencies.
References: http://easy2teach.net/database/what-is-relational-model-advantages-and-disadvantages-of-relational-model http://www.inf.unibz.it/~franconi/teaching/2000/ct481/er-modelling/
http://www.dummies.com/how-to/content/sql-criteria-for-normal-forms.html
Ricardo, C. (2012). Databases Illuminated, Second Edition. Sudbury, MA.
Jones & Bartlett Learning (Chapter 6 pg. 211-241)
Introduce the concept of normalization in a letter to the executive and explain the pros and cons.
The main purpose of normalization is to reduce data redundancy and avoid inconsistent data. The benefits on normalizing a database would be to prevent the appearance of modification anomalies in the data. The anomalies can lead to the loss of needed data. Normalization would help with organizing your data to prevent redundancy. It would also establish and maintain the integrity of your data tables as well as eliminating inconsistent data dependencies. Each table should describe only one type of entity.
Normalization leads to separation of unrelated entities into separate entities: The pros for normalization: The fully normalized expression of a data model is very close to the most compact possible representation of data in terms of bytes per unit of information, which would help with performance A well-normalized database is faster to write and to access for the same reason which would also be a plus for performance. Normalization would cause relational inconsistencies which would mean no redundancy.
The cons for normalization: Normalization requires skill to provide functional views and access methods that are comprehensible and streamlined for consumer …show more content…
OLTP applications Normalization requires discipline to maintain conceptually current and normalized Normalization requires skill and discipline to keep well-indexed They can be difficult & expensive to do well.
Explain the problems associated with data redundancy as it pertains to effectively using information for reporting and analysis.
Data redundancy occurs in database systems which have a field that is repeated in two or more tables.
Data redundancy leads to data anomalies and corruption and generally should be avoided by design. Normalization would prevent redundancy and make the best possible usage of storage. By following the principles of normalization you can achieve a design that is highly flexible allowing the model to be extended when needed to account for new attributes, entity sets, and relationships. With normalization we can reduce redundancy, both to save space and to avoid inconsistencies in data which could affect information for reporting and
analysis.
Discuss your rationale for normalizing from your E-R Model and demonstrate:
The main reason to normalize a database is to prevent the appearance of modification anomalies in the data. Anomalies can lead to the loss of needed data or the introduction of spurious data. The process usually entails splitting two or more tables that together contain the same information. Each table in a fully normalized database deals with only one ideas.a. How you derived at your 3NF from the earlier assignment
An entity is in the first normal form if it contains no repeating groups. In relational terms, a table is in the first normal form if it contains no repeating columns. Repeating columns make your data less flexible, waste disk space, and make it more difficult to search for data. To convert to third normal form, remove attributes that depend on other descriptor key attributes.
b. The process you took in arriving at your 3NF
c. The three (3) step technique of transforming your data model into first normal form, second normal form, and third normal form
First Normal Form (1NF): Table must be two-dimensional, with rows and columns. Each row contains data that pertains to one thing or one portion of a thing. Each column contains data for a single attribute of the thing being described. Each cell (intersection of row and column) of the table must be single-valued. All entries in a column must be of the same kind. Each column must have a unique name. No two rows may be identical. The order of the columns and of the rows does not matter.
Second Normal Form (2NF): Table must be in first normal form (1NF). All nonkey attributes (columns) must be dependent on the entire key.
Third Normal Form (3NF): Table must be in second normal form (2NF). Table has no transitive dependencies.
References: http://easy2teach.net/database/what-is-relational-model-advantages-and-disadvantages-of-relational-model http://www.inf.unibz.it/~franconi/teaching/2000/ct481/er-modelling/
http://www.dummies.com/how-to/content/sql-criteria-for-normal-forms.html
Ricardo, C. (2012). Databases Illuminated, Second Edition. Sudbury, MA.
Jones & Bartlett Learning (Chapter 6 pg. 211-241)