Most Frequently Asked Informix interview questions
The Informix database was designed by Roger Sippl in the late 1970s and was initially developed in his company Informix Corporation and later in April 2001; IBM acquired it.
A chunk is a physical portion of the disk on which the Informix stores its data. A fragment can be a raw partition or a file system file.
An Informix instance is a database server which manages the one or more than one Informix databases.
The Database object is a table or a view or any other type of objects supported by Informix. The Database objects are created using a statement SQL CREATE for these types of objects, and the database objects have owners.
A large binary object which is also known as a Blob is a collection of the binary data which is stored as a single entity in a database management system. Blobs are the audio or the images or the other multimedia objects.
Informix database uses a concept which is called key-value locking. Key Value locking is used to lock the deleted row. When the server deletes a row, then the critical values in the indexes of the table are not removed immediately. Instead, each key value is marked as deleted, and a lock is placed on the critical value.
Informix 4GL is a fourth-generation database which was developed in the mid-'80s. Informix 4GL provides the flexibility to work without the use of third generation programming languages like COBOL. Informix 4GL is mostly used in developing business applications.
- Informix 4GL database can handle the NULL values as the inputs and outputs within an Informix 4GL function.
- Informix 4GL database does not require the input or output parameters when publishing or subscribing to a web service.
- Informix 4GL database clients can also process structured data such as ARRAYs and RECORDs from the other 4GL applications.
- Informix 4GL database now includes the direct support for file I/O
A light scan is the sequential data scan of the data tables when the number of pages in the table is more than the number of buffers in the buffer pool.
There are four joins in the Informix:-
- INNER JOIN
- LEFT / RIGHT OUTER JOIN
- FULL OUTER JOIN
- CROSS JOIN
- DIRTY READ: Dirty Read Reads the data without checking whether the data is committed or not. During the read, no locks are held.
- COMMITTED READ: Committed Read reads only the determined data. During the read, no locks are held.
- REPEATABLE READ: Reads only the committed data. In this read, a shared lock is held on the rows. Other sessions can get the shared locks on those rows, but no one can get an exclusive lock.
- CURSOR STABILITY