Retrieving data from a database involves using a query to filter information from a given table or several tables that are related. In the health industry, databases would be created to store information is areas such as hospital demographics and staffing, patients data, electronic health records, health information exchanges, data for research and advocacy and pharmaceutical records [ CITATION CEB14 l 1033 ]. Commonly used queries and pseudo-queries would involve logical commands that filter and display the required information at a given time. Some of the common queries used in retrieving data are: equal to, greater than, less than, less or equal to, and greater or equal to mainly used when filtering number values logical queries such as AND, OR, NOT, containing the letter “e” , having the word “patient” and action queries such as delete, make table, append, and update.
Supposea hospital has a database table named patient which has the followinginformation: patient (patientnum,last name, first name, age, gender, street, city), to retrieve datafor patients who are aged 50 years and above, a query like “>=50” would be created in the age key. This would result in adisplay of all patients aged 50 years and above.
Sharing information from different fields in different tables can be coordinated by the use of relationships created between the tables. Such relationships can be grouped as on-to-one, one-to-many, or many-to-many relationship. In the implementation of a many-to-many relationship within the physical design, the keys are worked out such that several records in one table can be matched or related with several other matching records on another table. To create a many-to-many relationship between two given tables, the primary keys in the tables are determined first. A new table is then created that within which the keys in the table are the primary keys of the other tables to be related. Consider a case where a table named department and another table named employee are to be related. Suppose the third table to be created is named departmentemployee. Then creating a many-to-many relationship will involve using the primary key for the table department and the primary key for the table employee as foreign keys in the table departmentemployee [ CITATION Pra l 1033 ]. The table departmentemployee is a representation of the fact that a department could have many employees and an employee can work in many departments in the hospital [ CITATION CEB14 l 1033 ]. The departmentemployee table therefore gives us a many-to-many relationship. A primary key can be natural, artificial or surrogate and it is the foreign key in the new table that creates the required relationship between the tables. Note that the relationship between the employee and departmentemployee table is a one-to-one relationship.
There are several ways in which data can be collected or gathered and stored in a database. Each method of data collection has its own pitfall and there is no single method sufficient enough to solely satisfy database requirements in an institution like a hospital. The main methods of data collection include focus groups, key informant interviews, community forums and public meetings, surveys and community resource inventories. Key pitfalls that should be avoided in such cases include making decisions from data collected from a small group or sample and assuming that it would be significant to the larger population issuing threats to the key informants when conducting an interview advancing preconceived notions and ideas and being insensitive to contradictions and counter ideas from informants especially in community forums and public meetings [ CITATION Min14 l 1033 ] forcing customers to respond to too many questions on assumption that they have read the questions before responding to them.
Ifsuch pitfalls are not avoided, then the threshold of databaserequirements from the customers might not be met because such datawould be inaccurate leading to insufficient databases. Respondentscan also be unfaithful, sketchy and unrealistic in their responses.
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Minessota department of health. (n.d.). Retrieved june 26, 2014, from state.mn: www.health.state.mn.us/communityeng/…
Pratt, & J.P. concepts of database management. cengage learning.