Rushdi Shams, Dept of CSE, KUET 1
Database SystemsDatabase Systems
TablesTables
Data TypesData Types
Version 1.0Version 1.0
2Rushdi Shams, Dept of CSE, KUET
Basics of TableBasics of Table
 In a data model, table is a bucket where youIn a data mo...
3Rushdi Shams, Dept of CSE, KUET
Basics of TableBasics of Table
 In the table, the column goes on in a horizontalIn the t...
4Rushdi Shams, Dept of CSE, KUET
Basics of TableBasics of Table
 In the table, the row goes on in a vertical fashion.In t...
5Rushdi Shams, Dept of CSE, KUET
Basic of TableBasic of Table
 Books contain relatively disorganized dataBooks contain re...
6Rushdi Shams, Dept of CSE, KUET
Relation / TableRelation / Table
 In relational data model, the table is also calledIn r...
7Rushdi Shams, Dept of CSE, KUET
Relation / Table (continued)Relation / Table (continued)
5.5. Duplicate rows are not allo...
8Rushdi Shams, Dept of CSE, KUET
Characteristics of a TableCharacteristics of a Table
9Rushdi Shams, Dept of CSE, KUET
TerminologyTerminology
 The number of rows in a table is calledThe number of rows in a t...
10Rushdi Shams, Dept of CSE, KUET
Creating TableCreating Table
 This SQL command willThis SQL command will
create a table...
11Rushdi Shams, Dept of CSE, KUET
Creating Table (continued)Creating Table (continued)
 Each of the column hasEach of the...
12Rushdi Shams, Dept of CSE, KUET
Creating Table (continued)Creating Table (continued)
 Each column has someEach column h...
13Rushdi Shams, Dept of CSE, KUET
Creating Table (continued)Creating Table (continued)
 The NOT NULL field is theThe NOT ...
14Rushdi Shams, Dept of CSE, KUET
Data TypesData Types
 Now, we will plunge into data types for more.Now, we will plunge ...
15Rushdi Shams, Dept of CSE, KUET
Simple Data TypesSimple Data Types
 As the name mentions, they are really simplyAs the ...
16Rushdi Shams, Dept of CSE, KUET
Simple Data Types (continued)Simple Data Types (continued)
 If you limit the number of ...
17Rushdi Shams, Dept of CSE, KUET
Simple Data Types (continued)Simple Data Types (continued)
18Rushdi Shams, Dept of CSE, KUET
Simple Data Types (continued)Simple Data Types (continued)
 Numbers:Numbers: numerical ...
19Rushdi Shams, Dept of CSE, KUET
Simple Data Types (continued)Simple Data Types (continued)
 Fixed length decimals:Fixed...
20Rushdi Shams, Dept of CSE, KUET
Simple Data Types (continued)Simple Data Types (continued)
 Date and time:Date and time...
21Rushdi Shams, Dept of CSE, KUET
Simple Data Types (continued)Simple Data Types (continued)
22Rushdi Shams, Dept of CSE, KUET
About other data typesAbout other data types
 Complex and specialized data types- I wil...
23Rushdi Shams, Dept of CSE, KUET
Data DictionaryData Dictionary
 It is called database designer’s databaseIt is called d...
24Rushdi Shams, Dept of CSE, KUET
Data Dictionary (continued)Data Dictionary (continued)
25Rushdi Shams, Dept of CSE, KUET
ReferenceReference
 Beginning Database Design by Gavin Powell,Beginning Database Design...
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My slide tables & data types

  1. 1. Rushdi Shams, Dept of CSE, KUET 1 Database SystemsDatabase Systems TablesTables Data TypesData Types Version 1.0Version 1.0
  2. 2. 2Rushdi Shams, Dept of CSE, KUET Basics of TableBasics of Table  In a data model, table is a bucket where youIn a data model, table is a bucket where you pour data.pour data.  Data in a specific table is associated with allData in a specific table is associated with all other items in that table.other items in that table.  In a table, there are basically 3 things-In a table, there are basically 3 things- 1.1. Rows / Records / TuplesRows / Records / Tuples 2.2. Columns / Attributes / FieldsColumns / Attributes / Fields 3.3. DataData
  3. 3. 3Rushdi Shams, Dept of CSE, KUET Basics of TableBasics of Table  In the table, the column goes on in a horizontalIn the table, the column goes on in a horizontal fashion.fashion.  ISBN, AUTHOR, PUBLISHER, TITLE, GENRE,ISBN, AUTHOR, PUBLISHER, TITLE, GENRE, PRINTED are the column names for this tablePRINTED are the column names for this table
  4. 4. 4Rushdi Shams, Dept of CSE, KUET Basics of TableBasics of Table  In the table, the row goes on in a vertical fashion.In the table, the row goes on in a vertical fashion.  Every row in this table has data for ISBN, AUTHOR,Every row in this table has data for ISBN, AUTHOR, PUBLISHER, TITLE, GENRE, PRINTEDPUBLISHER, TITLE, GENRE, PRINTED
  5. 5. 5Rushdi Shams, Dept of CSE, KUET Basic of TableBasic of Table  Books contain relatively disorganized dataBooks contain relatively disorganized data  Organize information using modelOrganize information using model  Resulting in a neatly structured set of rows and columnsResulting in a neatly structured set of rows and columns
  6. 6. 6Rushdi Shams, Dept of CSE, KUET Relation / TableRelation / Table  In relational data model, the table is also calledIn relational data model, the table is also called relation. There are set of rules that are applied on therelation. There are set of rules that are applied on the relations. You must have to know them.relations. You must have to know them. 1.1. A database contains many relations. Every relations inA database contains many relations. Every relations in a database must have distinct namesa database must have distinct names 2.2. Every column in a relation must have distinct namesEvery column in a relation must have distinct names 3.3. Every entries in a column must be in the same domainEvery entries in a column must be in the same domain 4.4. The ordering of columns in a relation is insignificantThe ordering of columns in a relation is insignificant
  7. 7. 7Rushdi Shams, Dept of CSE, KUET Relation / Table (continued)Relation / Table (continued) 5.5. Duplicate rows are not allowed in a relationDuplicate rows are not allowed in a relation 6.6. The ordering of rows is insignificantThe ordering of rows is insignificant 7.7. Multiple values are not allowed in the cells of aMultiple values are not allowed in the cells of a relationrelation 8.8. 2 rows in a relation may contain the same2 rows in a relation may contain the same value for 1 columns but not in all (deviation ofvalue for 1 columns but not in all (deviation of 5)5)
  8. 8. 8Rushdi Shams, Dept of CSE, KUET Characteristics of a TableCharacteristics of a Table
  9. 9. 9Rushdi Shams, Dept of CSE, KUET TerminologyTerminology  The number of rows in a table is calledThe number of rows in a table is called CardinalityCardinality  The number of columns in a table is calledThe number of columns in a table is called DegreeDegree
  10. 10. 10Rushdi Shams, Dept of CSE, KUET Creating TableCreating Table  This SQL command willThis SQL command will create a table named Studentcreate a table named Student  Student will have 6Student will have 6 columns-columns- 1.1. IDID 2.2. NameName 3.3. AddressAddress 4.4. Date_of_BirthDate_of_Birth 5.5. YearYear 6.6. SemesterSemester CREATE TABLE Student (CREATE TABLE Student ( IDID VARCHAR(10)VARCHAR(10) NOTNOT NULL,NULL, NameName VARCHAR(20),VARCHAR(20), AddressAddress VARCHAR(20),VARCHAR(20), Date_of_BirthDate_of_Birth DATE,DATE, YearYear INTEGER(1),INTEGER(1), SemesterSemester INTEGER(1)INTEGER(1) ););
  11. 11. 11Rushdi Shams, Dept of CSE, KUET Creating Table (continued)Creating Table (continued)  Each of the column hasEach of the column has a definite Data Type.a definite Data Type. Different vendors ofDifferent vendors of DBMS have differentDBMS have different data types.data types.  In choosing themIn choosing them appropriately, you willappropriately, you will have to go through theirhave to go through their documentations! Theydocumentations! They are huge!are huge! CREATE TABLE StudentCREATE TABLE Student (( IDID VARCHAR(10)VARCHAR(10) NOT NULL,NOT NULL, NameName VARCHAR(20),VARCHAR(20), AddressAddress VARCHAR(20),VARCHAR(20), Date_of_BirthDate_of_Birth DATE,DATE, YearYear INTEGER(1),INTEGER(1), SemesterSemester INTEGER(1)INTEGER(1) ););
  12. 12. 12Rushdi Shams, Dept of CSE, KUET Creating Table (continued)Creating Table (continued)  Each column has someEach column has some predefined length onpredefined length on data types.data types.  As in ID, the ID of aAs in ID, the ID of a student can be withstudent can be with maximum length of 10maximum length of 10 and so on.and so on. CREATE TABLE StudentCREATE TABLE Student (( IDID VARCHAR(10)VARCHAR(10) NOT NULL,NOT NULL, NameName VARCHAR(20),VARCHAR(20), AddressAddress VARCHAR(20),VARCHAR(20), Date_of_BirthDate_of_Birth DATE,DATE, YearYear INTEGER(1),INTEGER(1), SemesterSemester INTEGER(1)INTEGER(1) ););
  13. 13. 13Rushdi Shams, Dept of CSE, KUET Creating Table (continued)Creating Table (continued)  The NOT NULL field is theThe NOT NULL field is the last thing to know here. Iflast thing to know here. If you think that any of youryou think that any of your columns of your tablecolumns of your table MUST NOT be NULL,MUST NOT be NULL, then you specify it.then you specify it.  If you don’t specify it,If you don’t specify it, during inserting data,during inserting data, anyone may leave thatanyone may leave that empty. But if you specifyempty. But if you specify NOT NULL, then theNOT NULL, then the column MUST have a valuecolumn MUST have a value for each of its row.for each of its row. CREATE TABLE Student (CREATE TABLE Student ( IDID VARCHAR(10)VARCHAR(10) NOTNOT NULL,NULL, NameName VARCHAR(20),VARCHAR(20), AddressAddress VARCHAR(20),VARCHAR(20), Date_of_BirthDate_of_Birth DATE,DATE, YearYear INTEGER(1),INTEGER(1), SemesterSemester INTEGER(1)INTEGER(1) ););
  14. 14. 14Rushdi Shams, Dept of CSE, KUET Data TypesData Types  Now, we will plunge into data types for more.Now, we will plunge into data types for more.  Though vendor to vendor data types vary, theyThough vendor to vendor data types vary, they have some generic types.have some generic types. 1.1. Simple data typesSimple data types 2.2. Complex data typesComplex data types 3.3. Specialized data typesSpecialized data types
  15. 15. 15Rushdi Shams, Dept of CSE, KUET Simple Data TypesSimple Data Types  As the name mentions, they are really simplyAs the name mentions, they are really simply applied on the data in a tableapplied on the data in a table  Strings:Strings: a string is a sequence of characters. Ita string is a sequence of characters. It can be fixed length strings and variable lengthcan be fixed length strings and variable length strings.strings.
  16. 16. 16Rushdi Shams, Dept of CSE, KUET Simple Data Types (continued)Simple Data Types (continued)  If you limit the number of characters in this kind ofIf you limit the number of characters in this kind of strings, then it takes exactly the same number ofstrings, then it takes exactly the same number of characters. CHAR is this type of data type. If you saycharacters. CHAR is this type of data type. If you say CHAR (3) and put NY there, then it will storeCHAR (3) and put NY there, then it will store NY<SPACE> in that columnNY<SPACE> in that column  In contrast, a variable length string allows you to putIn contrast, a variable length string allows you to put data up to a value defined by the user.data up to a value defined by the user. VARCHAR(10) means this column allows you toVARCHAR(10) means this column allows you to put 10 characters at mostput 10 characters at most TEXT (N) is another variable length string!TEXT (N) is another variable length string!
  17. 17. 17Rushdi Shams, Dept of CSE, KUET Simple Data Types (continued)Simple Data Types (continued)
  18. 18. 18Rushdi Shams, Dept of CSE, KUET Simple Data Types (continued)Simple Data Types (continued)  Numbers:Numbers: numerical data types. Should Inumerical data types. Should I say more about them?say more about them?   There are loads of numerical data types-There are loads of numerical data types- 1.1. SMALLINTSMALLINT 2.2. INTEGERINTEGER 3.3. LONGLONG 4.4. FLOATFLOAT 5.5. NUMBERNUMBER
  19. 19. 19Rushdi Shams, Dept of CSE, KUET Simple Data Types (continued)Simple Data Types (continued)  Fixed length decimals:Fixed length decimals: Sometimes, you will need to fix theSometimes, you will need to fix the number of characters in a decimal likenumber of characters in a decimal like DECIMAL (5,2). From vendor to vendorDECIMAL (5,2). From vendor to vendor this may differ.this may differ. With this, it can be like-With this, it can be like- 1.1. It will allow 12345.67 orIt will allow 12345.67 or 2.2. It will allow 123.45It will allow 123.45
  20. 20. 20Rushdi Shams, Dept of CSE, KUET Simple Data Types (continued)Simple Data Types (continued)  Date and time:Date and time: Date and time may be formatted asDate and time may be formatted as follows-follows- 1.1. dd/mm/yyyydd/mm/yyyy 2.2. timstamptimstamp
  21. 21. 21Rushdi Shams, Dept of CSE, KUET Simple Data Types (continued)Simple Data Types (continued)
  22. 22. 22Rushdi Shams, Dept of CSE, KUET About other data typesAbout other data types  Complex and specialized data types- I will try toComplex and specialized data types- I will try to discuss them when time will seem appropriatediscuss them when time will seem appropriate for me!for me! 
  23. 23. 23Rushdi Shams, Dept of CSE, KUET Data DictionaryData Dictionary  It is called database designer’s databaseIt is called database designer’s database  During creation of database tables, oftenDuring creation of database tables, often engineers keep track of their tables by dataengineers keep track of their tables by data dictionarydictionary  It is not mandatory but recommendedIt is not mandatory but recommended  Contains every possible information about theContains every possible information about the tables in a databasetables in a database
  24. 24. 24Rushdi Shams, Dept of CSE, KUET Data Dictionary (continued)Data Dictionary (continued)
  25. 25. 25Rushdi Shams, Dept of CSE, KUET ReferenceReference  Beginning Database Design by Gavin Powell,Beginning Database Design by Gavin Powell, Wrox Publications, 2005Wrox Publications, 2005  Database Systems: Design, ImplementationDatabase Systems: Design, Implementation & Management by Rob & Coronel, 6& Management by Rob & Coronel, 6thth EditionEdition

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