DBS201: More on SQL Lecture 2

Agenda Review How to create a table How to insert data into a table Terms Lab 2

Review Data Anomalies What is a database? What is a DBMS? What are three categories of SQL statements Use three letters to describe each category On IBM i platform What command is used to initiate an interactive SQL session? How do you construct a container for Tables and Views A collection is also called two other names - ?

How to Create a Table First write a Database Structure chart. We can also call this a Data Dictionary of your table. Column Type Length PK FK reference Req’d ? Unique ? Validation

How to Create a Table Type: Length: Numeric Decimal Character Varchar Date ‘yyyy-mm-dd’ Do not specify a length Time Length: Specify positions to the left of the decimal point and positions to the right of the decimal point

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 part of the PK, otherwise leave blank

How to Create a Table FK Reference: Req’d?: 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

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

Definition of a Table Format for defining the table PAINTER: Column Type Len PK FK Req’d Unique Validation PTR_NUM CHAR 4 Y PTR_LNAME 15 PTR_FNAME PTR_CITY 20 PTR_PHONE DEC 10

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

Deleting a ‘Database’ To remove a ‘database’, use the DROP COLLECTION statement Syntax DROP COLLECTION ‘database name’

Creating Tables in SQL CREATE TABLE Syntax Used to create a table CREATE TABLE tablename (field1 datatype fieldsize, field2 datatype fieldsize, …. CHECK …, PRIMARY KEY (fieldname(s)), FOREIGN KEY (fieldname) REFERENCES tablename (PKfieldname))

Creating Tables in SQL CREATE TABLE painter ( p_num char (4) not null with default, p_lname char (15) not null with default, p_fname char (15) not null with default, p_city char (20), p_phone dec (10), Constraint Painter_p_num_PK Primary Key (p_num) )

Creating Tables in SQL INSERT INTO WS201J40/PAINTER (P_NUM, P_FNAME, P_CITY) VALUES('111', 'BILL', 'TORONTO') 1 rows inserted in PAINTER in WS201J40. SELECT * FROM PAINTER

Creating Tables in SQL

Creating Tables in SQL CREATE TABLE painter ( p_num char (4), p_lname char (15) not null, p_fname char (15) not null, p_city char (20), p_phone dec (10), Constraint Painter_p_num_PK Primary Key (p_num) )

Creating Tables in SQL INSERT INTO WS201J40/PAINTER (P_NUM, P_FNAME, P_CITY) VALUES('111', 'BILL', 'TORONTO') Null values not allowed in column or variable P_LNAME

Creating Tables in SQL Primary Key Constraint initially not done: Table created without a primary key constraint p_phone dec (10) ) ALTER TABLE PAINTER ADD CONSTRAINT PAINTER_p_num_PK PRIMARY KEY (p_num)

Dropping Tables in SQL DROP TABLE Syntax Used to remove a table DROP TABLE tablename

Inserting Data into a Table Used to insert data into a table Syntax INSERT INTO tablename (fieldname1, fieldname2,….) VALUES (value1, value2…) or INSERT INTO tablename VALUES (value1, value2…), (value1, value2…) Single row added Multiple rows added

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

Primary Keys in SQL Primary Key Primary Key must always be NOT NULL (and unique) What happens if you create the table without specifying a primary key, insert rows and then apply the primary key constraint?

Inserting a Row INSERT INTO PAINTERA40/PAINTER VALUES('111', 'Smith', 'Bill', 'Oakville', 905477333) INSERT INTO PAINTERA40/PAINTER VALUES('222', 'Brown', 'Nancy', 'Mississauga', 9055666633)

Inserting Data into a Table INSERT INTO PAINTERA40/PAINTER (p_num, p_lname, p_fname, p_city, p_phone) VALUES('111','Wong', 'Ben', 'Newmarket', 9058876644) Can we add the primary key constraint ? ALTER TABLE PAINTER ADD CONSTRAINT Painter_p_Num_PK PRIMARY KEY (P_Num) Unique index cannot be created because of duplicate keys.

SQL Terminology S C H E M A A group of related objects that consists of a library, a journal, a journal receiver, an SQL catalog, and an optional data dictionary. A schema enables the user to find the table, view and index objects by name. Another name for a schema is collection.

SQL Terminology Transaction Control Language The journal and journal receiver in a DB2 schema, support TCL statements With before and after images of transactions stored, multi table operations are supported with a Commit or Rollback TCL statement

SQL Terminology T A B L E A set of columns and rows. R O W The horizontal part of a table containing a serial set of columns. C O L U M N The vertical part of a table of one data type

Equivalent SQL Terminology L I B R A R Y A group of related objects that enables the user to find the objects by name. A schema is treated the same as a library by some native commands. P H Y S I C A L F I L E A set of records. A Table is treated the same as a Physical File by native and SQL commands

Equivalent SQL Terminology R E C O R D A set of fields. F I E L D One or more bytes of related information of one data type. In SQL this is referred to as a column.

PART Table – What can you identify? PART NUMBER PART DESC ON HAND CLASS WAREHOUSE PRICE AX12 Iron 104 HW 3 23.95 AZ52 Dartboard 20 SG 2 12.95 BA74 Basketball 40 1 29.95 BH22 Cornpopper 95 24.95 BT04 Gas Grill 11 AP 149.99 BZ66 Washer 52 399.99 CA14 Griddle 78 39.99 CB03 Bike 44 299.99 CX11 Blender 112 22.95 CZ81 Treadmill 68 349.99

Table Exercise 1: Create a table called AGENT using the following data dictionary: Insert the following data into your table: Column Type Len PK FK Req’d Unique Validation AGT_NUM CHAR 3 Y AGT_LNAME 25 AGT_FNAME 20 AGT_AREACODE AGT_PHONE 7 AGT_NUM AGT_LNAME AFT_FNAME AGT_AREACODE AGT_PHONE 5 Andrews Mark 416 123-3456 10 Chen Terry 250 333-4059 15 DaSilva Lila 234-5837 20 Edwards George 444-5959 25 Eustace Gina 519 948-8494

Table Exercise 2: Create a table using the following data dictionary: Insert the following data into your table: Column Type Len PK FK Req’d Unique Validation CUST_NUM DEC 3 Y 1-100 CUST_LNAME CHAR 25 CUST_FNAME 20 CUST_AREACODE AGENT_NUM AGENT (AGENT_NUM) CUST_NUM CUST_LNAME CUST_FNAME CUST_AREACODE CUST_PHONE 5 Andrews Mark 416 123-3456 10 Chen Terry 250 333-4059 15 DaSilva Lila 234-5837 20 Edwards George 444-5959 25 Eustace Gina 519 948-8494

Agenda Lab 2