In common usage, validation is the process of checking whether something satisfies a certain criterion or not. Examples include checking whether a statement is true (validity) or not, whether an appliance works as intended or not, whether a computer system is secure or not, or whether computer data is compliant with an open standard or not.

Validation implies that one is able to document that a solution or process is correct or is suited for its intended use.

According to computer terminology, validation refers to the process of data validation, ensuring that data inserted into an application satisfies per-determined formats or complies with stated length and character requirements and other defined input criteria. It may also ensure that only data that is either true or real can be entered into a database.

With Validation function web database builder has become a really powerful tool. With the help of this service you can increase your database fields greatly. When you make a form by means of a Form Builder module click on Validation link, you will see the window, in which you can select a required validation type.

Detailed description of form creator validations types :

• No duplicate entries

This option allows you to check record uniqueness (in field string); presence in database alike importance (for fields integer, float); make sure that the files and images are conducted with alike names (for fields file, image); also for fields language, country, time zone validation uniqueness allows you to check presence of such a record; for field check box the given option allows you to choose a particular element from the list only once.

• Validate only on Submit.

The given option is additional to all. Having chosen it a user indicates that check by field is produced only after clicking on the button "Create".

• Can't be blank

The User installs check of record presence in a field.

• Number of characters

It is possible to set the necessary length of a field. The length option has three parameters (Is, Minimum, Maximum);

• Format 

You can add regular expression here. 

• Inclusion

Inclusion validation (for fields string, text) enables a user to define an introduced text in the forms fields strictly. A User can indicate what kind of text must be entered in a record field not allowing entering other words/phrases. The option has three additional parameters (Partial match, Case sensitive, Allow null): Partial match – using this parameter a user allows to enter a word or a phrase, which contains a record in field Within; Case sensitive provides a possibility to include/disconnect register; Allow null – a user can leave the field empty.

• Exclusion

Exclusion validation (for fields string, text) enables a user to define an introduced text in the forms fields strictly. A User can indicate what kind of text can not be entered in a record field, allowing entering other words/phrases. The option has three additional parameters (Partial match, Case sensitive, Allow null): Partial match - using this parameter a user allows to enter a word or a phrase, which contains a record in field Within; Case sensitive provides a possibility to include/disconnect register; Allow null - a user can leave the field empty.

• Only upload (default value)

This is an option for fields File, Images. Files or images are loaded from the Forms page and are important for a base by default.

• Acceptance

The given option is used for a field check box in events if it is necessary to accept some information on a form.

Regular expressions

You can use this validation for mobile number checking.
Example:

/^[ 1 ]\d{6,15}$/ – USA phone number format. Starts with the 1 then from 6 to 15 digit.

/^([ 2 ][ 1 ][ 2 ]|[ 3 ][ 1 ][ 5 ]|[ 3 ][ 4 ][ 7 ]|[ 5 ][ 1 ][ 6 ]|[ 5 ][ 8 ][ 5 ]|[ 6 ][ 0 ][ 7 ]|[ 6 ][ 3 ][ 1 ]|[ 6 ][ 4 ][ 6 ]|[ 7 ][ 1 ][ 6 ]|[ 7 ][ 1 ][ 8 ]|[ 8 ][ 4 ][ 5 ]|[ 9 ][ 1 ][ 4 ]|[ 9 ][ 1 ][ 7 ])\d{7}$/ – NY phone codes.

/^([ 0 ][ 8 ][ 0 ][ 0 ]|[ 8 ][ 0 ][ 0 ])\d{7}$/ – For free 800 or 0800 numbers.

/^([+][ 3 ][ 3 ]|[ 3 ][ 3 ])\d{8,9}$/ – For France numbers, format +33 or 33 and from 8 to 9 digits

/^[A-Z][a-z]*$/ - For uppercase first letter

Also, you can use Phone field.

In Andvanced options tab you can choose an input mask or enter your own (Another).