1. 1 DBS201: More on SQL Lecture 2

2. 2 Agenda Select command review How to create a table How to insert data into a table

3. 3 SQL Select Command SELECT statement Used to list contents of table Syntax SELECT Field1, Field 2,… FROM tablename WHERE Condition 1 AND/OR Condition 2 ORDER BY Field1, Field 2,…

4. 4 SQL Select Command BOOK_CODETITLEPUBLISHER_CODETYPEPRICEPAPERBACK 180A Deepness in the SkyTBSFI7.99Y 189Magic TerrorFAHOR7.99Y 200The StrangerVBFIC8.00Y 378Ve niceSSART24.50N 790Second WindPUMYS24.50N 808The EdgeJPMYS6.99Y 1351DreamcatcherSCHOR19.60N 1382Treasure ChestsTAART24.46N 1390BelovedPLFIC12.95Y Book Table:

5. 5 SQL Select Command 1. Write the select command to display all records 2. Write the select command to list all books that cost $24.50 3. Write the select command to list all books that are paperback and sort them by title

6. 6 How to Create a Table Now ready to convert an ER Model into a Database Structure Create a Data Dictionary of your table ColumnTypeLengthPKFK referenceReq’d ? Unique ? Validation

7. 7 How to Create a Table Type: Numeric Decimal Character Varchar Date Time Length: Specify positions to the left of the decimal point and positions to the right of the decimal point

8. 8 How to Create a Table Primary Keys For concatenated Primary Keys, pay close attention to the order of the attributes within the Primary Key Indexing starts with the first attribute mentioned, then proceeds to the next attribute and so on PK: Specify ‘Y’ if this column name is a PK, otherwise leave blank

9. 9 How to Create a Table FK Reference: Specify the table name and the column name where this field is a PK Req’d?: PKs, by default are required If this column must be present, specify ‘Y’ Means that this column can not be left blank or NULL – enforces data integrity

10. 10 How to Create a Table Unique?: Means only that the value in this column can only appear once Validation: Specify the range of values or the specific values that are allowed for this column

11. 11 Definition of a Table Format for defining the table PAINTER: ColumnTypeLenPKFKReq’dUniqueValidation PTR_NUMCHAR4YYY PTR_LNAMECHAR15 Y PTR_FNAMECHAR15Y PTR_AREACODECHAR3 PTR_PHONECHAR8

12. 12 Creating a ‘Database’ CREATE COLLECTION Used to create a ‘database’ Syntax CREATE COLLECTION ‘database name’

13. 13 Creating a ‘Database’ To remove a ‘database’, use the DROP COLLECTION statement Syntax DROP COLLECTION ‘database name’

14. 14 Creating Tables in SQL CREATE TABLE Used to create a table Syntax CREATE TABLE tablename column 1 data type, column 2 data type, …. CONSTRAINT …

15. 15 Definition of a Table Format for defining the table PAINTER: ColumnTypeLenPKFKReq’dUniqueValidation PTR_NUMCHAR4YYY PTR_LNAMECHAR15 Y PTR_FNAMECHAR15Y PTR_AREACODECHAR3 PTR_PHONECHAR8

16. 16 Creating Tables in SQL Create statement for painter might look like: CREATE TABLE painter ( ptr_num char (4) not null with default, ptr_lname char (15) not null with default, ptr_fname char (15) not null with default, ptr_areacode char (3), ptr_phone char (8), Constraint ptr_num_pk Primary Key(ptr_num) Constraint ptr_num_un Unique(ptr_num))

17. 17 Creating Tables in SQL Constraints: CHECK option when creating a table Specified as follows: Use comparison operators (i.e. =) Can use AND as well as OR Can use BETWEEN (to specify a range of values) i.e. ….CHECK (fieldname BETWEEN 1 AND 50) (assumes fieldname is a numeric type) i.e. ….CHECK (fieldname BETWEEN ‘1’ AND ’50’) (assumes fieldname is a char type)

18. 18 Dropping Tables in SQL DROP TABLE Used to delete a table Syntax DROP TABLE tablename

19. 19 DATE Data Type On the AS/400, date type is expected in the format: ‘mm/dd/yy’ Do not specify a length

20. 20 Creating Tables in SQL Rules for creating tables Parent tables must be defined before child tables Conversely, child tables must be deleted before parent tables Primary Key must always be NOT NULL (and unique)

21. 21 Inserting Data into a Table INSERT Used to insert data into a table Syntax INSERT into tablename (fieldname1, fieldname2,….) VALUES (value1, value2…)

22. 22 Inserting Data into a Table Rules for Inserting: Include all column names and provide values for each column If table was created allowing NULLs, then indicate the word NULL in place of that column when specifying the values

23. 23 More on Creating Tables Constraints: Specified as follows: Use comparison operators (i.e. =) Can use AND as well as OR Can use BETWEEN (to specify a range of values) i.e. ….CHECK (fieldname BETWEEN 1 AND 50) (assumes fieldname is a numeric type) i.e. ….CHECK (fieldname BETWEEN ‘1’ AND ’50’) (assumes fieldname is a char type)

24. 24 More on Selecting Tables Using WHERE clause: Specifying conditions to be met: Can use comparison operators (i.e. =) Can use AND as well as OR Can use BETWEEN (to specify a range of values) i.e. ….WHERE fieldname BETWEEN 1 AND 50 (assumes fieldname is a numeric type) i.e. ….WHERE fieldname BETWEEN ‘1’ AND ’50’ (assumes fieldname is a char type)