Synonyms
Simplify access to objects by creating a synonym (another name for an object). With synonyms, you can:
• Ease referring to a table owned by another user
• Shorten lengthy object names
Query syntax
CREATE [PUBLIC] SYNONYM synonym
FOR object;
Eg:
CREATE PUBLIC SYNONYM dept
FOR alice.departments;
To find out Date, Time and Characterset format of Oracle server.
select * from v$nls_parameters;
NLS_LANGUAGE AMERICAN
NLS_TERRITORY
NLS_CURRENCY $
NLS_ISO_CURRENCY
NLS_NUMERIC_CHARACTERS .,
NLS_CALENDAR GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE AMERICAN
NLS_CHARACTERSET UTF8
NLS_SORT BINARY
NLS_TIME_FORMAT HH.MI.SSXFF AM
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY $
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_COMP BINARY
NLS_LENGTH_SEMANTICS BYTE
NLS_NCHAR_CONV_EXCP FALSE
FormUtils.setFormValues()
DynaActionForm dynaForm = (DynaActionForm) FormDefUtil.setFormValues("employeeForm", employee, this, mapping, request); The first parameter identifies the form definition that will be used.
The second parameter is the business object which contains the values that will be used to populate the form bean.
The last three parameters are the current Action object, the current action mapping, and the request being processed.
FormUtils.setFormValues() returns the populated form bean. This can then be placed by the caller in the proper scope with the proper name so that Struts can find it when rendering an HTML form.
Employee employee = (Employee) FormDefUtil.getFormValues(form, this, mapping, request); The first parameter is the form passed by Struts to the action object.
The next three parameters are the current Action object, the current action mapping, and the request being processed.
getFormValues() returns the business object populated with values from the form bean. If a factory is associated with the form definition, it is called to create the business object that will be populated. Otherwise, the business object's no-arg constructor will be used to create the object.
A foreign key means that values in one table must also appear in another table.
The referenced table is called the parent table while the table with the foreign key is called the child table. The foreign key in the child table will generally reference a primary key in the parent table.
A foreign key can be defined in either a CREATE TABLE statement or an ALTER TABLE statement.
The syntax for creating a foreign key using a CREATE TABLE statement is:
CREATE TABLE table_name
(column1 datatype null/not null,
column2 datatype null/not null,
...
CONSTRAINT fk_column
FOREIGN KEY (column1, column2, ... column_n)
REFERENCES parent_table (column1, column2, ... column_n)
);
For example:
| CREATE TABLE supplier | |||
| ( | supplier_id | numeric(10) | not null, |
| | supplier_name | varchar2(50) | not null, |
| | contact_name | varchar2(50), | |
| | CONSTRAINT supplier_pk PRIMARY KEY (supplier_id) | ||
| ); | |||
| CREATE TABLE products | |||
| ( | product_id | numeric(10) | not null, |
| | supplier_id | numeric(10) | not null, |
| | CONSTRAINT fk_supplier | ||
| | FOREIGN KEY (supplier_id) | ||
| | REFERENCES supplier(supplier_id) | ||
| ); | |||
In this example, we've created a primary key on the supplier table called supplier_pk. It consists of only one field - the supplier_id field. Then we've created a foreign key called fk_supplier on the products table that references the supplier table based on the supplier_id field.
example demonstrates how to manipulate text on the status bar. When you move the cursor over a hyperlink, the statusbar shows the destination URL. This is not very helpful. Fortunately, it is very easy to put our own brief description there.
The normal HTML code for a hyperlink might be something like this:
<A HREF="mylink.htm">Click here</A>
To display something on the status bar when the mouse is moved over this link, you need to add a little more:
<A HREF="mylink.htm" onMouseOver="window.status='Click
here to know more about me'; return true;" onMouseOut="window.status=''; ">Click here</A>
Simple query to find out the version of Oracle..
Select * from v$version;
Schema
A schema is a collection of objects, such as tables, views, database user and has the same name as that user.
Check this link for more info
http://www.oracle.com/technology/obe/2day_dba/schema/schema.htm#t1