Eastern Software Systems Interview Questions and Answers

Explanation of differences between PK & UK, Case & Decode, Procedure & Function, Cursor & Refcursor.

• PK (Primary Key) is a unique identifier for a record in a table, while UK (Unique Key) ensures uniqueness but allows null values.

• Case and Decode are conditional statements used to manipulate data based on certain conditions.

• Procedure and Function are both database objects used to perform a specific task, but Function ret...read more

Dual is a special one-row, one-column table in Oracle DB.

• Dual is used to perform calculations or execute functions without selecting from a table.

• It is often used to generate a sequence of numbers or to concatenate strings.

• For example, SELECT 1+1 FROM dual; will return 2.

• Dual is automatically created by Oracle and is always available in every Oracle database.

Collection in Oracle is a group of elements of the same data type. Types include VARRAY, Nested Table, and Associative Array.

• VARRAY is a fixed-size array that can hold a varying number of elements up to the specified limit.

• Nested Table is a dynamic array with no fixed size that can be stored in a database column.

• Associative Array is a collection of key-value pairs where the key is unique and used to access the correspo

A DB block is a unit of data storage in Oracle Forms that contains multiple rows of data from a database table.

• DB blocks are used to improve performance by reducing the number of times a form needs to access the database.

• Each DB block contains a fixed number of rows, which can be configured in the form's block properties.

• When a form needs to display data from a table, it reads one or more DB blocks into memory.

• If a for...read more

Call_Form is a built-in Oracle Forms procedure used to call another form from the current form.

• Call_Form is used to open a new form while keeping the current form open.

• It can be used to pass parameters between forms.

• The called form can be modal or non-modal.

• The called form can be in the same application or a different one.

• Syntax: Call_Form('form_name', [mode], [hide], [no_replace], [query_only], [params])

Types of Trigger in Oracle forms and their sequence of firing.

• Types of triggers include Key Triggers, Mouse Triggers, and Timer Triggers.

• Key Triggers fire when a key is pressed or released.

• Mouse Triggers fire when the mouse is clicked or moved.

• Timer Triggers fire at a specified interval.

• The sequence of trigger firing is Pre-Form, Pre-Block, Pre-Record, Post-Record, Post-Block, and Post-Form.

Canvas, LOV, and List button are UI components used in Oracle Forms.

• Canvas is a visual container used to display data or graphics.

• LOV (List of Values) is a drop-down list used to select a value from a predefined list.

• List button is a button used to display a list of values in a pop-up window.

• These components are commonly used in Oracle Forms to create user-friendly interfaces.

A placeholder column is a column that is used to reserve space for a future column in an Oracle report.

• Placeholder columns are used to ensure that the layout of a report remains consistent even if data is missing.

• They are typically used when a report is designed to display a fixed number of columns, but the data source may not always contain data for all of those columns.

• Placeholder columns can be added to a report by ...read more