Ch01 Access
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The document discusses preparing to automate data management through database design. The discovery phase involves gathering existing data, researching missing data, and talking to users about output needs. Key steps include organizing data into tables, identifying unique values for each record, and designing the database. Proper database design requires examining existing sources of data, researching missing sources, and planning how to organize data into logical groups and tables with appropriate field types and sizes. Factors like data duplication, redundancy, and naming conventions must also be considered to create an effective automated data management system.
Ch01 Access
- 1. Preparing to Automate Data Management1Chapter 1“You can use all the quantitative data you can get, but you stillhave to distrust it and use your own intelligence and judgment.” — Alvin Toffler
- 2. Chapter IntroductionDiscovery phase includesGathering all existing data Researching missing and incomplete dataTalking with users about data output needsSubsequent steps in process includePutting data into groups called tablesIdentifying unique values for each record in those tables Designing database to produce desired outputSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 2
- 3. Database Design Process: The Discovery PhaseSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 3
- 4. Level 1 Objectives: Examining Existing and Missing Sources of DataDiscover and evaluate sources of existing business dataResearch sources of missing or incomplete dataAssign data to tables and use field types and sizes to define dataSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 4
- 5. Discovering and Evaluating Sources of Existing DataIdentify information that organization needs to manage and organizeMight begin to see patterns that indicate how to organize dataDatabase management system (DBMS)Includes:Oracle ColdFusionMicrosoft AccessMySQLSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 5
- 6. Discovering and Evaluating Sources of Existing Data (cont’d)Data duplicationUndesirable Additional space required in database to store extra recordsLeads to inconsistent and inaccurate dataData redundancySame data repeated for different recordsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 6
- 7. Researching Sources of Missing DataPart of discovery phaseMust ask right questions of right people to get right answersSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 7
- 8. Assimilating the Available Information and Planning the DatabaseFirst step in database design Determine best way to organize data into logical groups of fieldsField Single characteristic of entityAlso called columnRecordValues in each field in tableAlso called rowSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 8
- 9. Assimilating the Available Information and Planning the Database (continued)TableCollection of fields that describe one entityAlso called entity or relationDatabaseCollection of one or more tablesRelational databaseContains related tables through fields that contain identical dataSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 9
- 10. Evaluating Field Values and Assigning Appropriate Data TypesData type Determines how to store data in fieldDBMSs use different names for some data typesHow do you determine which data type to assign each field? Depends on what function you want to derive from dataEach data type has different propertiesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 10
- 11. Common Data Types and Their DescriptionsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 11
- 12. The Text and Memo Data TypesText data typeLetters and numbersNot used in calculations or formulasStores maximum of 255 charactersDefault for all fields created in access databaseMemo data typeStore long passages of textDisplays only 64,000 charactersSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 12
- 13. The Number Data TypeStores both positive and negative numbers Contains up to 15 digitsUse for values used in calculationsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 13
- 14. The Currency Data TypeIncludes two decimal places and displays values with dollar signUse for monetary valuesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 14
- 15. The Date/Time Data TypeDisplay values in format mm/dd/yyyyCan also include time in different formatsUsed in calculations if necessarySucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 15
- 16. The AutoNumber Data TypeUnique to AccessNumber automatically generated by access Produces unique values for each recordUseful to distinguish two records that share identical informationProduces values of up to nine digitsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 16
- 17. The Yes/No Data TypeAssigned to fields requiring Yes/noTrue/falseOn/offTakes up one character of storage spaceMake data entry easyCheck boxSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 17
- 18. The OLE Object Data TypeUsed to identify files created in another program - Then linked or embedded in databaseAbbreviation for object linking and embeddingSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 18
- 19. The Hyperlink Data TypeAssigned to fields that contain hyperlinks to Web pagesE-mail addressesFiles that open in Web browserE-mail clientAnother applicationSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 19
- 20. The Lookup Wizard Data TypeCreates fields to look up data in Another tableOr list of values created for fieldMakes data entry easy Ensures that valid data entered into fieldSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 20
- 21. The Attachment Data TypeNew to Access 2007Lets you store one or more files for each record in the databaseSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 21
- 22. Selecting the Correct Data TypeHelps store correct data in correct format while using least amount of spaceEases data entry and interactivity with data Choosing certain data types results in user-friendly interactive featuresDrop-down menus Check boxesHyperlinksCorrectly manipulate dataSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 22
- 23. Assigning the Correct Field Size for Text FieldsImportant to consider field size when assigning data typesMinimize space reserved for each record by assigning smallest data type that will store dataBe conservative when assigning field sizesBut not too conservativeSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 23
- 24. Assigning the Correct Field Size for Number FieldsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 24
- 25. Dividing the Existing and Missing Data into TablesTables Single most important component of databaseMost databases contain Multiple tables Hundreds or even thousands of recordsPrimary key One field that creates unique value in each record Used to identify each record in tableMay be a combination of fieldsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 25
- 26. Database Design Process: Planning the TablesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 26
- 27. Naming ConventionsDatabase tables must Have unique namesFollow established naming conventions General rules for naming objectsObject names cannot exceed 64 charactersObject names cannot include period, exclamation point, accent grave, or bracketsObject names should not include spacesMost developers capitalize first letter of each word when table name includes two wordsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 27
- 28. Leszynski/Reddick Naming Conventions for Database ObjectsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 28
- 29. Level 1 SummaryDiscovery phaseIdentify existing and missing dataDetermine tablesDetermine data typesFollow naming conventionsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 29
- 30. Level 2 Objectives:Understanding and Creating Table RelationshipsUnderstand relational database objects and conceptsCreate table relationshipsUnderstand referential integritySucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 30
- 31. Understanding Relational Database ObjectsUsers can view data in tables by:Opening table Creating other objectsFour main objects in database TablesQueriesFormsReportsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 31
- 32. TablesData in relational database stored in one or more tablesView data in table Open it and scroll through recordsMost of the time, three other main database objects used to display data normallySucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 32
- 33. QueriesQuery Question asked about data stored in databaseQuery resultsLook similar to tableFields displayed in columns Records displayed in rowsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 33
- 34. Queries (continued)Select query Most commonly used queryData selected from table on which query basedAction queryPerforms action on tableSelect specific records in table and update them Crosstab query Performs calculations on values in field and displays results in datasheetSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 34
- 35. FormsUsed to view add delete, update and print records in databaseBased on table or queryInterface more attractive than table datasheetCustomize form’s appearance with instructions and command buttonsSwitchboard Form displayed when database openedProvides controlled method for users to open objects in databaseSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 35
- 36. Form Based on a TableSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 36
- 37. ReportsFormatted presentation of data from table or query Created as printout or to be viewed on screenData displayed by report usually based on queryDynamicReflect latest data from objectCannot be used to modify dataSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 37
- 38. Accounts Receivable ReportSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 38
- 39. Other Database ObjectsMacro Set of instructions Automate certain database tasksUsually automates simple tasksModule Contains instructions to automate database taskWritten in Visual Basic for Applications (VBA)Performs more sophisticated actions than macroSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 39
- 40. Understanding Relational Database ConceptsFlat file databaseSimple database Contains single table of informationRelational databaseContains multiple tables to store related informationCommon field Field that appears in two or more tables and contains identical data to relate tablesPrimary key in first tableForeign key in second tableSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 40
- 41. Creating Table RelationshipsTake advantage of interrelated objectsGoal in good database design Create separate tables for each entityEnsure each table has primary keyUse common field to relate tablesRelate two (or more) tablesQuery them as though they are one big tableJoin Specifies relationship between tables and properties of relationshipSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 41
- 42. One-to-Many RelationshipsAbbreviated as 1:MOne record in first table matches zero one or many records in related tablePrimary tableOne sideRelated tableMany sideSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 42
- 43. One-to-Many Relationship Between Customers and PrescriptionsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 43
- 44. One-to-One RelationshipsAbbreviated as 1:1Exists when each record in one table matches exactly one record in related tableSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 44
- 45. One-to-One Relationship Between Physical and Billing AddressesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 45
- 46. Many-to-Many RelationshipsAbbreviated as M:NEach record in first table matches many records in second tableEach record in second table matches many records in first tableJunction tableSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 46
- 47. Many-to-Many Relationship Between Employees and ClassesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 47
- 48. Understanding Referential IntegrityNull valueField does not contain any valueEntity integrityGuarantee that there are no duplicate records in tableEach record uniqueNo primary key field contains null valuesReferential integrity If foreign key in one table matches primary key in second table Values in foreign key must match values in primary keySucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 48
- 49. Understanding Referential Integrity (continued)When database does not enforce referential integrity Problems occur that lead to inaccurate and inconsistent dataOrphanedNo longer match between primary key in primary table and foreign keys in related tableSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 49
- 50. Referential Integrity ErrorsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 50
- 51. Overriding Referential IntegrityMight want to override referential integrity Intentionally change primary key Delete parent recordCascade updatesChange primary key value so that DBMS automatically updates appropriate foreign key values in related tableCascade deletesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 51
- 52. Level 2 SummaryMain database objects:TableQueryFormReportRelationship types:One-to-manyOne-to-oneMany-to-manySucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 52
- 53. Level 3 Objectives: Identifying and Eliminating Database Anomalies by Normalizing DataLearn the techniques for normalizing dataEvaluate fields that are used as keysTest the database designSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 53
- 54. Normalizing the Tables in the DatabaseNormalizationDesign processGoalsReduces space required to store data by eliminating duplicate data in databaseReduces inconsistent data in database by storing data only onceReduces chance of deletion update and insertion anomaliesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 54
- 55. Normalizing the Tables in the Database (continued)Deletion anomaly User deletes data from database Unintentionally deletes only occurrence of data in databaseUpdate anomaly Due to redundant data in databaseUser fails to update some records or updates records erroneouslyInsertion anomaly User cannot add data to database unless preceded by entry of other dataSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 55
- 56. Normalizing the Tables in the Database (continued)Functional dependencyColumn in table considered functionally dependent on another column If each value in second column associated with exactly one value in first columnPartial dependency Field dependent on only part of primary keyComposite primary keyPrimary key uses two or more fields to create unique records in tableSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 56
- 57. Normalizing the Tables in the Database (continued)DeterminantField or collection of fields whose value determines value in another fieldInverse of dependencyNatural keyPrimary key that details obvious and innate trait of recordArtificial keyField whose sole purpose is to create primary keyUsually visible to usersSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 57
- 58. Normalizing the Tables in the Database (continued)Surrogate key Computer-generated primary key Usually invisible to usersSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 58
- 59. First Normal FormRepeating groupField contains more than one valueFirst normal form 1NFDoes not contain any repeating groupsSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 59
- 60. Second Normal Form2NFTable must be in 1NF Must not contain any partial dependencies on composite primary keyTables in 1NF and contain primary key with only one field Automatically in 2NFSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 60
- 61. Third Normal Form3NFOnly determinants must be candidate keysCandidate key Field or collection of fields that could function as primary key but was not chosen to do soTransitive dependency Occurs between two nonkey fields both dependent on third fieldTables in 3NF should not have transitive dependenciesSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 61
- 62. Level 3 SummaryNormal formsFirst (1NF)Second (2NF)Third (3NF)Succeeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 62
- 63. Chapter SummaryDiscovery:Identify existing and missing dataOrganize data into tablesDetermine data types for each fieldTable relationshipsEstablished through common fieldsTypes1:M1:1M:NSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 63
- 64. Chapter Summary (continued)NormalizationReduces duplication and inconsistencyForms:1NF2NF3NFSucceeding in Business with Microsoft Office Access 2007: A Problem-Solving Approach 64