November 21, 2019

Srikaanth

Check Point Software MySQL Interview Questions Answers

What Are Some Good Ideas Regarding User Security In Mysql?

There is no user without a password. There is no user without a user name. There is no user whose Host column contains % (which here indicates that the user can log in from anywhere in the network or the Internet). There are as few users as possible (in the ideal case only root) who have unrestricted access.

Explain The Difference Between Myisam Static And Myisam Dynamic. ?

In MyISAM static all the fields have fixed width. The Dynamic MyISAM table would include fields such as TEXT, BLOB, etc. to accommodate the data types with various lengths. MyISAM Static would be easier to restore in case of corruption, since even though you might lose some data, you know exactly where to look for the beginning of the next record.

What Does Myisamchk Do?

It compressed the MyISAM tables, which reduces their disk usage.

Explain Advantages Of Innodb Over Myisam?

Row-level locking, transactions, foreign key constraints and crash recovery.
Check Point Software Most Frequently Asked Latest MySQL Interview Questions Answers
Check Point Software Most Frequently Asked Latest MySQL Interview Questions Answers

Explain Advantages Of Myisam Over Innodb?


Much more conservative approach to disk space management - each MyISAM table is stored in a separate file, which could be compressed then with myisamchk if needed. With InnoDB the tables are stored in tablespace, and not much further optimization is possible. All data except for TEXT and BLOB can occupy 8,000 bytes at most. No full text indexing is available for InnoDB. TRhe COUNT(*)s execute slower than in MyISAM due to tablespace complexity.

What Are Heap Tables In Mysql?

HEAP tables are in-memory. They are usually used for high-speed temporary storage. No TEXT or
BLOB fields are allowed within HEAP tables. You can only use the comparison operators = and <=>. HEAP tables do not support AUTO_INCREMENT. Indexes must be NOT NULL.

How Do You Control The Max Size Of A Heap Table?

MySQL config variable max_heap_table_size.

What Are Csv Tables?

Those are the special tables, data for which is saved into comma-separated values files. They cannot be indexed.

Explain Federated Tables?

Introduced in MySQL 5.0, federated tables allow access to the tables located on other databases on other servers.

What Is Serial Data Type In Mysql?

BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT

SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE

What Happens When The Column Is Set To Auto Increment And You Reach The Maximum Value For That Table?

It stops incrementing. It does not overflow to 0 to prevent data losses, but further inserts are going to produce an error, since the key has been used already.

Explain The Difference Between Bool, Tinyint And Bit. ?

Prior to MySQL 5.0.3: those are all synonyms. After MySQL 5.0.3: BIT data type can store 8 bytes of data and should be used for binary data.

Explain The Difference Between Float, Double And Real. ?

FLOATs store floating point numbers with 8 place accuracy and take up 4 bytes.

DOUBLEs store floating point numbers with 16 place accuracy and take up 8 bytes.

REAL is a synonym of FLOAT for now.

If You Specify The Data Type As Decimal (5,2), What's The Range Of Values That Can Go In This Table?

999.99 to -99.99. Note that with the negative number the minus sign is considered one of the digits.

What Happens If A Table Has One Column Defined As Timestamp?

That field gets the current timestamp whenever the row gets altered.

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