'return false;'

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Monday, October 27, 2008

QUICK SQL/PLSQL

Basic SQL commands
1.DDL (data retrival language)
*select
2.DML (data mnupulation language)
*Insert
*Update
*Delete
*Merge
3.DDL (data definiton language)
*Create
*Alter
*Rename
*Truncate
*Drop
4.TCL (data transaction language)
*Commit
*Savepoint
*Rollback
5.DCL (data control language)
*Grant
*revoke

Creating Tables
You must create your tables before you can enter data into them. Use the Create Table command.

Syntax:     Create table tablename using filename
        (fieldname fieldtype(length), 
         fieldname fieldtype(length), 
         fieldname fieldtype(length));
Explanation:
  • A Select statement is a SQL statement that begins with the word "select."
  • Select statements are used to retrieve data from SQL tables.
  • An asterisk after the word "select" means retrieve all fields (columns).
  • The name of the table from which you are retrieving data is specified in the From clause.
  • Use a semicolon to signify the end of a SQL statement.
Create table TrnVendor using 'TVendor.dat' 
(VendId char(10), 
Name char(30), 
Add1 char(30), 
City char(30), 
State char(3), 
CurrBal float(8), 
ExpAcct char(10));

Retrieving All Data   

Select statements are used to retrieve data from  SQL tables. The Select statement illustrated below retrieves all of the columns and rows  from the named table.Syntax:    Select *  from tablename;

Explanation:
§  A Select statement is a SQL statement that begins with the word "select."
§  Select statements are used to retrieve data from SQL tables.
§  An asterisk after the word "select" means retrieve all fields (columns).
§  The name of the table from which you are retrieving data is specified in the From clause.
§  Use a semicolon to signify the end of a SQL statement.
Example:
Retrieve all of the data from the TrnVendor table.
Select * from TrnVendor; 

Inserting Rows

You can insert new rows into a table by using insert command in SQL

Syntax:   Insert into tablename ( fieldname, fieldname, fieldname)  values ( value, value, value);

Explanation:
Ø     When inserting data, use the Start Transaction command so that any errors can be rolled back.
Ø    You must specify the values to be inserted.
Ø  When performing an insert, enclose character values in single quotes.
Ø   Do not enclose numeric values in single quotes.
Ø   Use the Rollback Work command to undo changes.
Ø   Use the Commit Work command to finalize changes.
Example:   Insert the following vendor into the TrnVendor table
VendorId        TV055
Name               PartyGames
Address           POBox136
City                 Chicago
State                IL
Current Balance: 2498.62
Insert into TrnVendor (VendId, Name, Addr1, City, State,  CurrBal )
values ( 'TV055', 'Party Games', 'PO Box 136', 'Chicago', 'IL', 2498.62);


Updating Tables