hap 709 – healthcare databases sql data manipulation language (dml) updated fall, 2009
TRANSCRIPT
SQL Components
SQL
DCL DDL DML
DBA Activities
Create UsersDelete UsersGrant privilegesImplement AccessSecurity
RDBMS Structure
Create/Delete DBs
Create/Delete TablesAlter Tables
Data I/O
Create Record
Read Record
Update Record
Delete Record
SQL is non-procedural
You do not need to tell the computer how to do the tasks. All you need to tell the
computer is what you want to see and the computer will figure out how to produce the
results you want to see
Typical Commands
• Details of commands are provided online. Here we review a select few commands
• Key words are reserved for command specifications. These words cannot be used as names for fields or tables.
Data Type Must be Specified
• Number– Integer, Small integer, Big integer, Numeric data (with
fraction), Decimal (with precision)
• String– Character, Large character, National character
• Boolean• Date/times
– Date, Time with and without time zone, Timestamp with and without time zone
• Intervals
Data Manipulation Commands
• Combined numeric values
• Calculate intervals among dates/times
• Process a series of Boolean statements
• Concatenate strings together
Logical Connectives
• Allows you to build complex predicates out of simple ones
• Set functions– Count, Max, Min, Sum, Avg, Stdev
• Sub-queries
Using SQL with Microsoft Access
• Open database and select queries from objects
• Select create query in design view• Add tables and close add tables button• Choose SQL view• Delete the select statement and enter
commands you want• When finished save and enter a name for
the query
INSERT INTO Syntax
INSERT INTO <myTable> VALUES(<Field1> <DataType>, <Field2> <DataType>,…);
INSERT INTO PAT VALUES(983883,'JOHN','MARTINEZ');
UPDATE Statement (1)
UPDATE <myTable> SET<Field1> = <Value1> WHERE {condition};
UPDATE PAT SET PAT_FNM = 'JOHNNY' WHERE PAT_ID = 983883;
Updating Multiple Records(1)
A new field needs to be populated after modification of the original table structure
UPDATE Statement (2)
UPDATE <myTable> {join} SET<Field1> = <Value1> WHERE {condition};
UPDATE PAT INNER JOIN TEMP ON PAT.PAT_ID = TEMP.PAT_ID SET PAT.PAT_TITLE = TEMP.TITLE ;
UPDATE Statement (3)
UPDATE <myTable> SET<Field1> = <Value1> WHERE {condition};
UPDATE MED_PROCEDURE SET COST = 1.125 * COST ;
Reading the Data: the SELECT Statement
SELECT {fields || *} FROM <myTable> {condition};
SELECT PAT_LNM FROM PAT;
SELECT * FROM PAT;
SELECT MED_PROC_NM FROM MED_PROCEDURE WHERE COST > 20000;
Natural Join
SELECT PAT_FNM, PAT_LNM, CLNCIAN_NM FROM PAT, CLNCIANWHERE PAT.PAT_ID = CLNCIAN.PAT_IDAND PAT_FNM = 'MARY'AND PAT_LNM = 'LINDFORS';
Who is/are the primary physician(s) for patient Mary Lindfors?
Outer Joins: RIGHT JOIN
SELECT PAT.PAT_FNM, PAT.PAT_LNM, CLNCIAN.CLNCIAN_NMFROM CLNCIAN RIGHT JOIN PAT ON CLNCIAN.PAT_ID = PAT.PAT_ID;
Shows all the records from PAT and those records from CLNCIAN where the PAT_ID values are equal in both tables
LEFT JOIN
SELECT PAT.PAT_FNM, PAT.PAT_LNM, CLNCIAN.CLNCIAN_NMFROM CLNCIAN LEFT JOIN PAT ON CLNCIAN.PAT_ID = PAT.PAT_ID;
Shows all the records from CLNCIAN and those records from PAT where the PAT_ID values are equal in both tables
Union Operator
• The tables must have the same number of columns
• Corresponding columns must all have identical data types and lengths
• Command syntaxSelect * From <First Table name>
Union
Select * From <Second Table name>;
Intersect
• Only rows of data that appear in both source tables are selected
• Command SyntaxSelect * From <Table name>
Intersect Corresponding (<Fieldname>, <Fieldname>, …)
Select * From <Second Table name>;
Except
• Return all rows that appear in first table but not in the second table
Select * From <Table name>
Except Corresponding (<Fieldname>, <Fieldname>, …)
Select * From <Second Table name>;