The refresh rate of a display is the number of times per second that the image refreshes on the screen. For example, a 60Hz display will update the screen 60 times per second.

References

Windows Doc

To find the constraints in a table

ALL_CONSTRAINTS: Provides information about all constraints accessible to the user, across all tables in the database. It includes constraint types, status, and more, but doesn’t show column-specific details.

SELECT * FROM ALL_CONSTRAINTS 
WHERE TABLE_NAME='YOUR_TABLE_NAME' 
AND OWNER = 'OWNER_NAME';

To find the constarints referring to a table.

SELECT * FROM ALL_CONSTRAINTS 
WHERE R_CONSTRAINT_NAME IN ( 
    SELECT CONSTRAINT_NAME FROM ALL_CONSTRAINTS 
    WHERE TABLE_NAME='YOUR_TABLE_NAME' 
    )
AND OWNER = 'OWNER_NAME';

USER_CONS_COLUMNS: Shows details about columns associated with constraints for tables owned by the current user. It’s useful for checking specific columns involved in constraints like primary keys, foreign keys, or unique constraints.

SELECT CONSTRAINT_NAME, TABLE_NAME, COLUMN_NAME, POSITION
FROM USER_CONS_COLUMNS
WHERE TABLE_NAME = 'YOUR_TABLE_NAME';

Sometimes we want to load the CSS asynchronously to reduce the intial page load and you can do the same by adding media="print" onload="this.media='all' to the link as below.

<link rel="stylesheet" href="/path/to/my.css" media="print" onload="this.media='all'">

Let’s dive into the details of the above:

• The link’s media attribute is set to print.
• print is a media type that applies to print-based media or when the user tries to print the page.
• By using media="print", the CSS file loads asynchronously (since it’s not needed immediately for screen display).
• However, we still want to apply the styles to the page for screen use.
• To achieve this, we can use the onload attribute to change the link’s media to all once it finishes loading.

References

filamentgroup

The RETURNING INTO clause allows us to return column values for rows affected by DML statements. The returned data could be a single column, multiple columns or expressions.

INSERT INTO t1 VALUES (t1_seq.nextval, 'FOUR')
RETURNING id INTO l_id;

References

Oracle, dba-oracle, oracle base