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Mini EECS User's Guide for SQL*Plus
T. J. Teorey Table of Contents
Oracle/logging-in SQL create table/naming rules Update commands Select commands Set operations Built-in functions 1 2 3 3 4 4 Nested subqueries Complex functions Save a query/perm table Special commands SQL views Index 5 6 6 6 9 10
Oracle
Oracle 8.1.6 resides on a Sun Sparc10 node. However, you do not need to login directly to this machine, but think of it as a database server to be accessed from another machine, for example, canoe.engin.umich.edu.
Logging in to UNIX and Oracle SQL*Plus
login: <your Unix login-id> password: <your Unix login-password> your-unix-node% source /usr/caen/oracle/local/muscle your-unix-node% sqlplus Enter user-name: <your-oracle-id> Enter password: <your-oracle-password> /*You are now in SQL*Plus and can start issuing SQL*Plus commands*/ SQL> select * from employee; /*example of an sqlplus command*/ SQL> grant connect to your-oracle-id identified by your-new-password; /*change password*/
Input and Output Files for Oracle
To save the transcript of an sqlplus session or part of a session: SQL> set echo on; /*displays SQL code with results of the query*/ SQL> spool <filename>; /*filename will be appended with .1st if a postfix is not provided*/ SQL> spool off; /*will turn off the transcript spooling. You can now print the file with the instructions provided below*/ To read in a file: SQL> start <filename>; or SQL> @<filename>; where filename must be a OpSys file ending with .sql (the .sql may or may not be supplied to Oracle, but must be part of the name of the file).
Print Oracle Results
To print on a Sun or IBM the users can say: lpr -P<printer_name> <filename> printer_names (2340eecss2,2341eecsh1,4327eecss1,4327eecss2,4440eecss1,4440eecsm1) HP: lp -d<printer_name> <filename>
Access from any computer:
1. To any UNIX machine, by typing "telnet <node_name>" 2. To any UNIX machine from a Merit terminal (where you see the "Which Host?"prompt), by doing a "telnet <host>@engin.umich.edu" Note: use "telnet hostinfo" to see a selection of free nodes.
Oracle SQL*Plus Programming Examples
Naming rules:
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1-30 characters long (a-z, 0-9,_,$,#), begin with a letter No quotation marks No duplicates of Oracle reserved words, no duplicate of another Oracle object of the same type Basic example: suppliers, parts, and shipments. create table supplier (snum number not null, sname char(12), /*max is 240 characters*/ city char(12), status number, primary key (snum)); /*must be defined as a primary key before it is defined as a foreign key*/ create table part (pnum number not null, pname char(10), length number, weight number, primary key (pnum)); /*cannot have both "unique" and primary key*/ create table shipment (snum number not null, pnum number not null, qty number, shipdate date not null, primary key (snum, pnum,shipdate), foreign key (snum) references supplier, foreign key (pnum) references part);
Syntax Rules
1. Semicolon needed, no continuation character needed. 2. not => !, ~(hat), not(.....) 3. Constraints on create table not null - null not allowed for this column (attribute) unique - attribute may not have duplicate values primary key - explicitly designates simple or composite primary key foreign key - explicitly specifies referential integrity check - specifies range constraints or specific values (see 5-39) 4. Logical operators used with "where" clause: and, or, not, !=, () 5. Comparison operators: (),=,!=,~=,<,<=,>,>= in - equal to any member of, same as "=any" not in - same as "!= all" => false of any member of set (select...) is null any - same as "in" all - compares a value to every value returned by a list 6. Set operators union - combines queries to display any row in each subquery intersect - combines queries to display distinct rows common to all subqueries minus - combines queries to return all distinct rows returned by the first query but not the second 7. Order by: asc, desc 8. Basic definitions create table - defines a table alter table - add a new column, lengthen the width of a column /*enlargements only*/. drop table - destroys an existing base table create view, drop view create index, drop index..........create index x on t (p,q desc, r); create integrity, drop integrity 9. Data types:
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number (integer, 31 bits), smallint (15 bits) (p[q]), p digits total, q to the right of the decimal point float, real (not in Oracle), double precision (not in Oracle) char(n), character(n), varchar(n), date
Update Commands
alter table: alter table supplier modify (sname varchar(12)); alter table supplier add (address char(20) not null); insert (a single row): insert into supplier values (1,'Smith','Detroit',10); delete (one or more rows): delete from supplier where status > 1; update: update shipment set qty = 450 where qty = 500 and snum =3 and pnum = 31;
Select commands
/*display the entire supplier table*/ select * from supplier; /*display supplier number, status for all suppliers in London ..... Note: case sensitive within the quotes*/ select snum, status from supplier where city = 'London'; /*display all supplier and shipped part information, but omitting suppliers with status of 40*/ select s.*, sh.* from supplier s, shipment sh where s.snum = sh.snum and s.status != 40; /*use multiple table invocations to determine manager's name, one level above employee*/ select f.ename from emp e, emp f where e.ename = 'Smith' and f.empno = e.mgrno;
Set operations
/*which parts (part numbers) are shipped by supplier 1 or supplier 2?*/ select pnum, snum from shipment -ORselect pnum, snum from shipment where snum = 1 where snum = 1 or snum = 2; union select pnum, snum from shipment -ORselect pnum, snum from shipment where snum =2; where (snum = 1 or snum =2); /*which parts (part numbers) are shipped by both suppliers 1 and 3?*/ select pnum from shipment CANNOT DO THIS: where snum =1 select pnum from shipment intersect where snum = 1 and snum = 3; select pnum from shipment
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where snum = 3;
Built-in functions
/*display the total number of suppliers*/ select count(*) from supplier; /*display the total number of suppliers actually shipping parts*/ select count (distinct snum) from shipment; /*display the average quantity of a shipment of part number 31*/ select avg (qty) from shipment where pnum = 31; /*order by attribute names -- note that asc is the default*/ select pnum, snum, qty from shipment order by pnum asc, snum desc; /*order by column number as specified in the select line*/ select pnum, snum, qty from shipment order by 1, 2; /*for each part shipped, display the part number, the total shipment quantity, and the count of orders for each part; note that pnum in the select line must be in a "group by" command*/ select pnum, sum(qty), count(qty) from shipment group by pnum; /*note: the group by orders items ascending by default*/ /*display part numbers for all parts supplied by more than one supplier*/ select pnum from shipment group by pnum having count(distinct snum) >1; /*group by primary, secondary columns*/ select pnum, snum, max(qty) from shipment group by pnum,snum; /*find greatest and least values among attributes within each row, for all rows*/ select greatest(empno,mgrno), ename from emp;
Nested subqueries
/*display supplier names who supply part 32.....and equivalent query*/ select s.sname select s.sname from supplier s from supplier s, shipment sh where s.snum in where s.snum = sh.snum (select snum and sh.pnum = 32; from shipment sh where sh.pnum = 32); /*note indentation for nested query*/
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/*display supplier names who supply at least one part with weight over 20.....&...equiv query*/ select s.sname select s.sname from supplier s from supplier s, shipment sh, part p where s.snum in where s.snum = sh.snum (select sh.snum and sh.pnum = p.pnum from shipment sh and p.weight > 20; where sh.pnum = any (select p.pnum from part p where p.weight > 20)); /*which suppliers are currently not shipping any parts with weight over 20? select s.sname from supplier s where s.snum not in (select sh.snum from shipment sh, part p where sh.pnum = p.pnum and p.weight > 20);
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Complex computational functions
/*how much has Smith made while working for this company?*/ select sum(s.monsal*months_between(sh.enddate,sh.startdate)) from emp e, salhist sh, salary s where e.ename = 'Smith' and e.empno = sh.empno and sh.sallevel = s.sallevel; /*same query, but what if the last enddate is null?*/ select sum(s.monsal*(months_between(nvl(sh.enddate,sysdate),sh.startdate))) emp from e, salhist sh, salary s where e.ename = 'Smith' and e.empno = sh.empno and sh.sallevel = s.sallevel; Note: nvl(expr1, expr2) = expr1 if it is not null, or expr2 if expr1 is null greatest(expr1, expr2,..........) returns the greatest value among the given expressions least (expr1, expr2, ..........) returns the least value among the given expressions
Save a query result into a permanent table or just rename columns
create table supplier_part(suppname, shipqty, shipdate, partname) as (select s.sname, sh.qty, sh.shipdate, p.pname from supplier s, shipment sh, part p where s.snum = sh.snum and sh.pnum = p.pnum);
Special commands in SQL*Plus
1. Look at table schema: List tables you can access Look at your table privileges: SQL> desc table_name; SQL> select owner, table_name from all_tables; SQL> select * from user_tab_privs where table_name = '...........'; /*UC*/
2. How to rename tables from the all_tables list available to you; SQL> create synonym emp for teorey.emp; 3. How to copy a permitted (granted) table into your personal account: SQL> create table new_table_name as (select * from old_table_name); 4. Grant permission for read-only for a new public file: SQL> grant select on table_name to public; 5. Change password in SQL*Plus: SQL> grant connect to user_id identified by new_password; 6. Help commands: SQL> help; SQL> help commands; SQL> help select; /*general help information*/ /*lists commands you can get help on*/ /*any command or clause such as from, joins*/
7. Using a prompt to input data: SQL> select * from emp where job = '&which_job' and sal= '&&salary'; /*does prompt*/ SQL> run; /*for & - repeats prompt*/
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SQL> run; /*for && - redoes query with same value as before*/ Note: & means prompt with value, not saved; && means prompt with value, value is saved. 8. Setting up a report title, suppress the title, and set up special column headings: SQL> ttitle [right|left] 'This is a Title of a Report' ; /*default is center persists until you execute "ttitle off"*/ SQL> column schema_column_name heading new_column_name ; /*This will produce special column names as specified in quotes, but does not SQL> select ename "Employee Name", sal "Employee Salary" from emp; SQL> select ename empnane, sal empsalary from emp; 9. Report formatting: SQL> break on deptno skip 1; /*do not repeat deptno, skip a line between deptno's*/ SQL> break on deptno on mgr skip 1; /* do not repeat deptno or mgr, skip a line*/ SQL> run; /*execute the previous select with the new breaks*/ /*Note: you need to leave a blank line between the end of the query and the "run". This will cause echoing of the query. */ SQL> clear break; SQL> clear column; /*resets break and column settings*/ SQL> set pagesize 54; /*overrides default of 14 lines/page*/ 10. Data Formats: set column settings to override defaults, in-line format specifications SQL> column avg(sal.monsal) format $99,999.99; SQL> column deptname format A6; SQL> column deptno format 99999; SQL> ..........where to_char(shipdate, 'yy') = 94..........etc. SQL> select to_char(monsalary, '$99,999.99').......etc. SQL> alter session set NLS_DATE_FORMAT = DD-MON-YYYY; /*display 4-digit year*/ 11. Recursive hierarchy access in SQL*Plus (top-down hierarchy) SQL> select lpad(' ',2*level)||ename organization_chart from emp connect by prior empno = mgrno start with ename = 'King'; Note: a bottom-up hierarchy can be obtained by reversing the attributes after "connect by 12. Partial matching (see also SOUNDEX for words that sound like something else) /* Look for names with "a" as the second letter and any string afterwards */ SQL> select ename from emp where ename like '_a%'; 13. Size check -- determine the count of rows satisfying the query before displaying the results select count(*) from shipment where pnum = 31; Size check -- limit display of rows before displaying the results of the whole query. select snum, pnum from shipment where pnum = 31 and rownum <= 15; 14. Create sequence command to set up artificial primary key, max. number is 10*e**27 -1.
persist. Quote
prior" and spec
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SQL> create sequence myseq increment by 1 start with 1; /*defaults incr to 1 start with 1*/ SQL> create table mytable (myseq, attri1....., attr2 ....., attr3); SQL> insert into mytable values (myseq.nextval, value for attr1, .........) SQL> alter sequence mseq increment by 5; 15. Create index commands for B+-tree SQL> create [unique] index indexname on supplier(snum [asc|desc]); /*unique=> hashing*/ SQL> create unique index indexname on supplier(snum); /*unique index on primary key*/ SQL> create index indexname on shipment (shipdate); /*non-unique index on non-key*/ SQL> create index index2 on shipment (pnum, shipdate); /*non-unique concatenated index*/ 16. Check clause in create table commands. check (status>10), check (status between 10 and 40), check (city in ('Athens','London'), check (city != 'Paris' or status = 20); 17. SQL editing line-by-line SQL> select * from supplier 2 where snum = 14 3 and sname = 'Smith'; no rows selecte...