SQL
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SQL is a language used to manage data in relational database management systems. It allows users to define, manipulate, and control access to data. Some key points about SQL: - SQL is used to query, insert, update, and manipulate data stored in tables. It represents data as rows and columns. - It works with many programming languages and applications. Data can be retrieved using SELECT statements and inserted using INSERT statements. - SQL databases store data in tables which can then be related to each other using operations like joins. This relational model allows flexible data retrieval and reporting.
SQL
- 1. 1 Harshad D. UmredkarHarshad D. Umredkar MCA-II (Sem-II)MCA-II (Sem-II) SQL
- 2. a.Overview b.Uses c.requirement d.Design e.Queries f. Types of Tables g.Table h.Conclusion i. Reference s IndexIndex
- 3. 3 An Overview ofAn Overview of SQLSQL • SQL stands forSQL stands for SStructuredtructured QQueryuery LLanguage.anguage. • It is the most commonly used relationalIt is the most commonly used relational database language today.database language today. • SQL works with a variety of different fourth-SQL works with a variety of different fourth- generation (4GL) programming languages,generation (4GL) programming languages, such as Visual Basic.such as Visual Basic. SQL
- 4. 4 SQL is used for:SQL is used for: • Data ManipulationData Manipulation • Data DefinitionData Definition • Data AdministrationData Administration • All are expressed as an SQL statementAll are expressed as an SQL statement or command.or command. SQL
- 5. 5 SQLSQL RequirementsRequirements • SQL Must be embedded in a programmingSQL Must be embedded in a programming language, or used with a 4GL like VBlanguage, or used with a 4GL like VB • SQL is a free form language so there is noSQL is a free form language so there is no limit to the the number of words per line orlimit to the the number of words per line or fixed line break.fixed line break. • Syntax statements, words or phrases areSyntax statements, words or phrases are always in lower case; keywords are inalways in lower case; keywords are in uppercase.uppercase. SQL Not all versions are case sensitive!Not all versions are case sensitive!
- 6. 6 SQL is a Relational DatabaseSQL is a Relational Database • Represent all info in database as tablesRepresent all info in database as tables • Keep logical representation of data independent from its physicalKeep logical representation of data independent from its physical storage characteristicsstorage characteristics • Use one high-level language for structuring, querying, andUse one high-level language for structuring, querying, and changing info in the databasechanging info in the database • Support the main relational operationsSupport the main relational operations • Support alternate ways of looking at data in tablesSupport alternate ways of looking at data in tables • Provide a method for differentiating between unknown values andProvide a method for differentiating between unknown values and nulls (zero or blank)nulls (zero or blank) • Support Mechanisms for integrity, authorization, transactions, andSupport Mechanisms for integrity, authorization, transactions, and recoveryrecovery A Fully Relational Database Management System must:A Fully Relational Database Management System must:
- 7. 7 DesignDesign • SQL represents all information in the form of tables • Supports three relational operations: selection, projection, and join. These are for specifying exactly what data you want to display or use • SQL is used for data manipulation, definition and administration SQL
- 8. 8 Rows describe the Occurrence of an Entity Table DesignTable Design SQ L Name Address Jane Doe 123 Main Street John Smith 456 Second Street Mary Poe 789 Third Ave Columns describe one characteristic of the entity
- 9. 9 Data Retrieval (Queries)Data Retrieval (Queries) • Queries search the database, fetch info,Queries search the database, fetch info, and display it. This is done using theand display it. This is done using the keywordkeyword SELECT SELECT * FROM publishersSELECT * FROM publishers pub_id pub_name address state 0736 New Age Books 1 1st Street MA 0987 Binnet & Hardley 2 2nd Street DC 1120 Algodata Infosys 3 3rd Street CA • TheThe ** Operator asks for every column inOperator asks for every column in
- 10. 10 Data Retrieval (Queries)Data Retrieval (Queries) • Queries can be more specific with a fewQueries can be more specific with a few more linesmore lines pub_id pub_name address state 0736 New Age Books 1 1st Street MA 0987 Binnet & Hardley 2 2nd Street DC 1120 Algodata Infosys 3 3rd Street CA • Only publishers in CA are displayedOnly publishers in CA are displayed SELECT *SELECT * from publishersfrom publishers where state = ‘CA’where state = ‘CA’
- 11. 11 Data InputData Input • Putting data into a table is accomplishedPutting data into a table is accomplished using the keywordusing the keyword INSERT pub_id pub_name address state 0736 New Age Books 1 1st Street MA 0987 Binnet & Hardley 2 2nd Street DC 1120 Algodata Infosys 3 3rd Street CA • Table is updated with new informationTable is updated with new information INSERT INTO publishersINSERT INTO publishers VALUES (‘0010’, ‘pragmatics’, ‘4 4VALUES (‘0010’, ‘pragmatics’, ‘4 4 thth Ln’, ‘chicago’,Ln’, ‘chicago’, ‘il’)‘il’) pub_id pub_name address state 0010 Pragmatics 4 4th Ln IL 0736 New Age Books 1 1st Street MA 0987 Binnet & Hardley 2 2nd Street DC 1120 Algodata Infosys 3 3rd Street CA Keyword Variable
- 12. 12 Types of TablesTypes of Tables • User Tables:User Tables: contain information that iscontain information that is the database management systemthe database management system • System Tables:System Tables: contain the databasecontain the database description, kept up to date by DBMSdescription, kept up to date by DBMS itselfitself There are two types of tables which make upThere are two types of tables which make up a relational database in SQLa relational database in SQL Relation Table Tuple Row Attribute Column
- 13. 13 Using SQLUsing SQL SQL statements can be embedded into a programSQL statements can be embedded into a program (cgi or perl script, Visual Basic, MS Access)(cgi or perl script, Visual Basic, MS Access) OROR SQ L Database SQL statements can be entered directly at theSQL statements can be entered directly at the command prompt of the SQL software beingcommand prompt of the SQL software being used (such as mySQL)used (such as mySQL)
- 14. 14 Using SQLUsing SQL To begin, you must first CREATE a databaseTo begin, you must first CREATE a database using the following SQL statement:using the following SQL statement: CREATE DATABASE database_nameCREATE DATABASE database_name Depending on the version of SQL being usedDepending on the version of SQL being used the following statement is needed to beginthe following statement is needed to begin using the database:using the database: USE database_nameUSE database_name
- 15. 15 Using SQLUsing SQL • To create a table in the current database, use the CREATE TABLE keyword CREATE TABLE authorsCREATE TABLE authors (auth_id int(9) not null,(auth_id int(9) not null, auth_name char(40) not null)auth_name char(40) not null) auth_id auth_name (9 digit int) (40 char string)
- 16. 16 Using SQLUsing SQL • To insert data in the current table, use the keyword INSERT INTO auth_id auth_name • Then issue the statement SELECT * FROM authors INSERT INTO authors values(‘000000001’, ‘John Smith’) 000000001 John Smith
- 17. 17 Using SQLUsing SQL SELECT auth_name, auth_citySELECT auth_name, auth_city FROM publishersFROM publishers auth_id auth_name auth_city auth_state 123456789 Jane Doe Dearborn MI 000000001 John Smith Taylor MI auth_name auth_city Jane Doe Dearborn John Smith Taylor If you only want to display the author’s name and city from the following table:
- 18. 18 Using SQLUsing SQL DELETE from authorsDELETE from authors WHERE auth_name=‘John Smith’WHERE auth_name=‘John Smith’ auth_id auth_name auth_city auth_state 123456789 Jane Doe Dearborn MI 000000001 John Smith Taylor MI To delete data from a table, use the DELETE statement:
- 19. 19 Using SQLUsing SQL UPDATE authorsUPDATE authors SET auth_name=‘hello’SET auth_name=‘hello’ auth_id auth_name auth_city auth_state 123456789 Jane Doe Dearborn MI 000000001 John Smith Taylor MI To Update information in a database use the UPDATE keyword Hello Hello Sets all auth_name fields to helloSets all auth_name fields to hello
- 20. 20 Using SQLUsing SQL ALTER TABLE authorsALTER TABLE authors ADD birth_date datetime nullADD birth_date datetime null auth_id auth_name auth_city auth_state 123456789 Jane Doe Dearborn MI 000000001 John Smith Taylor MI To change a table in a database use ALTER TABLE. ADD adds a characteristic. ADD puts a new column in the table called birth_date birth_date . . Type Initializer
- 21. 21 Using SQLUsing SQL ALTER TABLE authorsALTER TABLE authors DROP birth_dateDROP birth_date auth_id auth_name auth_city auth_state 123456789 Jane Doe Dearborn MI 000000001 John Smith Taylor MI To delete a column or row, use the keyword DROP DROP removed the birth_date characteristic from the table auth_state . .
- 22. 22 Using SQLUsing SQL DROP DATABASE authorsDROP DATABASE authors auth_id auth_name auth_city auth_state 123456789 Jane Doe Dearborn MI 000000001 John Smith Taylor MI The DROP statement is also used to delete an entire database. DROP removed the database and returned the memory to system
- 23. 23 Conclusion • SQL is a versatile language that can integrate with numerous 4GL languages and applications • SQL simplifies data manipulation by reducing the amount of code required. • More reliable than creating a database using files with linked-list implementation
- 24. 24 References • “The Practical SQL Handbook”, Third Edition, Bowman.
Editor's Notes
- #2: Frequently, presenters must deliver material of a technical nature to an audience unfamiliar with the topic or vocabulary. The material may be complex or heavy with detail. To present technical material effectively, use the following guidelines from Dale Carnegie Training®. Consider the amount of time available and prepare to organize your material. Narrow your topic. Divide your presentation into clear segments. Follow a logical progression. Maintain your focus throughout. Close the presentation with a summary, repetition of the key steps, or a logical conclusion. Keep your audience in mind at all times. For example, be sure data is clear and information is relevant. Keep the level of detail and vocabulary appropriate for the audience. Use visuals to support key points or steps. Keep alert to the needs of your listeners, and you will have a more receptive audience.
- #4: In your opening, establish the relevancy of the topic to the audience. Give a brief preview of the presentation and establish value for the listeners. Take into account your audience’s interest and expertise in the topic when choosing your vocabulary, examples, and illustrations. Focus on the importance of the topic to your audience, and you will have more attentive listeners.
- #5: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #6: In your opening, establish the relevancy of the topic to the audience. Give a brief preview of the presentation and establish value for the listeners. Take into account your audience’s interest and expertise in the topic when choosing your vocabulary, examples, and illustrations. Focus on the importance of the topic to your audience, and you will have more attentive listeners.
- #7: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #8: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #9: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #10: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #11: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #12: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #13: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #14: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #15: If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience.
- #24: Determine the best close for your audience and your presentation. Close with a summary; offer options; recommend a strategy; suggest a plan; set a goal. Keep your focus throughout your presentation, and you will more likely achieve your purpose.