ACTG 475 Notes PDF

Database Reading Terms: - Database management system (DBMS): the program that manages and controls access to the data base - Data base system: combination of the data base, the DBMS, and the application programs that use the data base...

Database Reading Terms: - Database management system (DBMS): the program that manages and controls access to the data base - Data base system: combination of the data base, the DBMS, and the application programs that use the data base - Data base administrator (DBA): the person responsible for the data base - Logical view: how user or programmer conceptually organizes and understands the data - Physical view: how and where the data are physically arranged and stored on disk, tape, CD-ROM, or other media - Record layout: How a record is displayed or laid out in a system - Program-data independence: separation of the logical and physical views of data - Schema: logical structure of the database - Conceptual-level schema: organization-wide view of the entire database - External-level schema: contains set of individual user views of portions of the data base - Subschema: each individual view described in external-level schema - Internal-level schema: low-level view of the data base; describes how data is actually stored - Data dictionary: contains information about the structure of the data base - Data definition language (DDL): Used to o 1. Build data dictionary o 2. Initialize or create the data base o 3. Describe the logical views for each individual user or programmer o 4. Specify any limitations or constraints on security imposed on a data base records or fields - Data manipulation language (DML): used for data maintenance; updating, inserting, and deleting portions of the data base - Data query language (DQL): used to interrogate the data base - Report writer: a language that simplifies report creation - Data mode: an abstract representation of the contents of a data base - Relational data model: everything in the database being stored in the form of tables - Relations: the tables stored inside a relational data model - Tuple: each row in these relations; contains data about a specific occurrence of the type of entity represented by that table - Entity integrity rule: ensures every row in every relation must represent data about specific object in the real world - Foreign key: an attribute in one table that is the primary key of another table - Primary key: attribute or combination of attributes that uniquely identifies a specific row in a table - Referential integrity rule: Every foreign key must either be null or have a value corresponding to the value of a primary key in another relation - Normalization: the process of following the guidelines for designing relational tables to create the data storage scheme This study source was downloaded by 100000891139108 from CourseHero.com on 10-14-2024 03:21:44 GMT -05:00 https://www.coursehero.com/file/34603231/Database-Accounting-Study-Guidedocx/  -Requirements analysis: identifying user information needs, defining the scope of the proposed data base system, and determining preliminary hardware and software requirements - Conceptual design: involves translating data requirements of different users into a conceptual model of the database - Logical design: involves choosing the type of DBMS that will be used and translating the conceptual model into a model that can be implemented in that type of DBMS - Physical design: translate logical schema into a model that describes the actual physical structures and access methods that will be used to implement the system using a specific DBMS package Data Modeling: - Data Modeling: the process of defining a data base so that it faithfully represents all aspects of the organization - REA data model: a conceptual modeling tool specifically designed to provide structure for designing AIS data bases - Resources: things that have economic value to the organization - Events: various business activities about which management wants to collect information for planning or control purposes - Agents: the people and organizations that participate in events and about whom information is desired for planning, control, and evaluation purposes - Entity-Relationship (E-R) diagram: one method for portraying a data base schema; shows various entities being modeled and the important relationships among them - Cardinality (of a relationship): indicates how many occurrences of one entity in the relationship can be linked to a single occurrence of the other entity in the relationship - Minimum cardinality (of a relationship): the fewest number of rows that can be involved in that relationship - Maximum cardinality (of a relationship): the largest number of rows that can be involved in that relationship - Concatenated keys: multiple-attribute primary keys Microsoft Access Technology: - Relational: o Data in table format o Smaller storage space required o Ad-hoc (on the fly) queries o BUT: cannot handle complex data types - Object-Oriented: o Data and instructions are encapsulated o Code can be reused o Can handle complex data types o BUT: Ad-hoc queries are harder to do DBMS Languages: - DDL (Data Definition Language): o Builds the data dictionary This study source was downloaded by 100000891139108 from CourseHero.com on 10-14-2024 03:21:44 GMT -05:00 https://www.coursehero.com/file/34603231/Database-Accounting-Study-Guidedocx/  o Creates database o Describes logical views for each individual programmer o Creates internal controls in system o Used by DBA & Programmers - DML (Data Manipulation Language): o Inserts, deletes, and updates data in the database o Used by DBA & Programmers - DQL (Data Query Language): o Interrogates the database o Retrieves, sorts, orders, and presents subsets of the database o Users of system use DQL to ask queries SQL: - complex language but can do a lot with the basic syntax: o Select: lists columns that should be displayed in response o From: lists the names of tables that contain those columns and joins tables o Where: lists of field values to be chose o Order by: sorts rows in the response table o Group by: groups rows in the response table according to values in chosen columns - Convert from QBE to SQL: o Fill in later Systems Development Life Cycle (SDLC): - Stages (What do accountants do in each stage?): o Planning: help determine feasibility of the proposed project o Requirements Analysis:  Identify user info needs o Design  Develop logical and physical models  Specify controls o Coding  If have good IT skills, may participate in coding stage o Implementation  Test accuracy of new database and application programs that use the data o Operation  Use the system to process transactions Relational Database Requirements: - Primary key must be unique - Every foreign key must either be null or have a value corresponding to the value of a primary key in another relation - Each column in a table must describe a characteristic of the object identified by the primary key - Each column in a row must be single-valued - The values in every row of a specific column must be of the same data type This study source was downloaded by 100000891139108 from CourseHero.com on 10-14-2024 03:21:44 GMT -05:00 https://www.coursehero.com/file/34603231/Database-Accounting-Study-Guidedocx/  - Neither column order nor row order is significant Enforcement of Referential Integrity: - Every foreign key must either be null or have a value corresponding to the value of a primary key in another relation Segregation of Duties: - Separations between the execution, recording, and authorization of the accounting duties o Prevents employees from changing data for his or her own benefit o Prevents employees very familiar with program controls from circumventing controls o Prevents an employee from authorizing a fraudulent program change and then making that change themselves How Database Queries are processed and how tables joined: - Each operation filters the data into a smaller and smaller temporary table until the final answer is reached and displayed o This final answer is called a dynaset - How tables are joined: o Using the DBMS and DQL to create the right combination of attributes to find the answer the query is looking for Database Normalization: - What it is for: seeks to ensure there are no data anomalies in a database design - 3 kind of data anomalies: o Insert anomaly: inability to insert or add data to a table because of a design problem o Delete anomaly: deleting certain data from a table inadvertently results in the loss of other related data which the user would like to retain o Update anomaly: a change in a data item must be performed in multiple locations rather than just one - 3 forms of database normalization: o 1st Normal Form:  Has no repeating groups  Existence of multiple cell values in one or more non-key attributes for a single primary key nd o 2 Normal Form:  Must be 1NF  Non-key attributes in the relation are functionally dependent on the entire primary key  Transitive dependency: dependency between non-key attributes; OR any functional dependency that does not originate from the primary key rd o 3 Normal Form:  Must be 2NF  All functional dependencies in the relation originate from the primary key  AKA no transitive dependencies This study source was downloaded by 100000891139108 from CourseHero.com on 10-14-2024 03:21:44 GMT -05:00 https://www.coursehero.com/file/34603231/Database-Accounting-Study-Guidedocx/  o Summary of the 3  1NF: no repeating groups in the relation  2NF: every non-field key is functionally dependent on the entire primary key  3NF: all functional dependencies in the relation originate from the primary key o Database Schemas:  The different ways of viewing the structure of the database This study source was downloaded by 100000891139108 from CourseHero.com on 10-14-2024 03:21:44 GMT -05:00 https://www.coursehero.com/file/34603231/Database-Accounting-Study-Guidedocx/ Powered by TCPDF (www.tcpdf.org)