Users' questions

How big should a VARCHAR be?

How big should a VARCHAR be?

Values in VARCHAR columns are variable-length strings. The length can be specified as a value from 0 to 65,535. The effective maximum length of a VARCHAR is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. See Section 8.4.

What does VARCHAR 500 mean?

I was doing some research on how SQL stores data on disk. MSDN states that when storring a varchar, only the length of the data itself is used plus two bytes. So, if you store “car” in a VarChar(50) it will take 5 bytes. But when you store “car” in a VarChar(500) it will also take 5 bytes.

How many bytes is VARCHAR?

2 bytes
The VARCHAR column will use 2 bytes or the VARCHAR column will use 1 byte, depending on the defined size in characters, and the character set. All VARCHAR columns defined such that it might require more than 255 bytes use 2 bytes to store the size.

Does VARCHAR max waste space?

3 Answers. A varchar will only use as much space as inputted as opposed to a char which will pad with white space. Traffic size on a varchar column, therefore, is considerably smaller than a char column. Correct, it will not make any difference.

Why varchar Max is bad?

In addition, varchar(max) prevents the ability to perform online indexes against the entire table which contains the varchar(max) field. Failure to do so is poor design and will lead to performance issues on any but the most trivial of systems.

What does varchar 100 mean?

varchar(100) means your variable FirstName can hold a value uuto hunder character, if the it is for 1000 it holds thousand characters. but unused characters do not consume storage. The storage will be n*1 byte+1= n1 bytes, in your case 100 = 100*1 byte +2 bytes=102 bytes.

What is varchar example?

VARCHAR is a variable length string data type, so it holds only the characters you assign to it. VARCHAR takes up 1 byte per character, + 2 bytes to hold length information. For example, if you set a VARCHAR(100) data type = ‘Jen’, then it would take up 3 bytes (for J, E, and N) plus 2 bytes, or 5 bytes in all.

Is it bad to use varchar Max?

Use varchar when the sizes of the column data entries vary considerably. Use varchar(max) when the sizes of the column data entries vary considerably, and the size might exceed 8,000 bytes. So varchar(MAX) is inappropriate fore columns like FirstName, where the value will never exceed 8,000 bytes.

Can VARCHAR be primary key?

It is perfectly acceptable to use a varchar column as the primary key. This is often the case when one uses a natural key that doesn’t happen to be an integer. Keep in mind that even if you introduce a surrogate as the pimary key, you’ll still need to create a unique constraint on product_id.

Does VARCHAR need length?

The answer is you don’t need to, it’s optional. It’s there if you want to ensure that strings do not exceed a certain length. From Wikipedia: Varchar fields can be of any size up to the limit.

Should I avoid nvarchar Max?

You cannot create an index on an nvarchar(MAX) column. You can use full-text indexing, but you cannot create an index on the column to improve query performance. For me, this seals the deal…it is a definite disadvantage to always use nvarchar(MAX).

Should I use varchar or text?

A VARCHAR can be part of an index whereas a TEXT field requires you to specify a prefix length, which can be part of an index. VARCHAR is stored inline with the table (at least for the MyISAM storage engine), making it potentially faster when the size is reasonable.

Why is everything varchar ( 255 ) and 511 ( 31 )?

That’s why everything was VARCHAR (255) and VARCHAR (31). Out of habit the 255 seems to have stuck around but the 31’s became 32’s and the 511’s became 512’s. That part is weird.

What’s the difference between varchar ( 1024 ) and 512?

So the difference between varchar (1024) and varchar (512) is, that your data gets truncated when you try to insert more than 1024 or 512 bytes. Note: bytes, not characters. How much bytes each character uses is dependent on the character set you’re using. There is a actually a difference.

When was 512 assigned as an area code?

Area code 512 serves the state of Texas. This area code was assigned on January 1st, 1947. On January 1st, 1947 it went into service. 512 is a General Purpose Code. 512 service area does overlap with 737 area codes. Dialing pattern for local calls within the same NPA (area code) is 10D. 1stel, Inc. – Tx 365 Wireless, Llc Air & Wire Netwo…

How many bytes are needed for varchar ( 255 )?

What I read ” With a maximum length of 255 characters, the DBMS can choose to use a single byte to indicate the length of the data in the field. If the limit were 256 or greater, two bytes would be needed.”