Most voted "single-restriction" questions
You can use the UNIQUE constraints to make sure that there are no duplicated values typed in specific columns that do not participate in any primary key of a database table.
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20
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answers17226
viewsDifference in Index Unique and Unique Constraint usage in Mysql?
I would like to know the behavior/differences between a Indice Unique and Unique Constraints to the Mysql ? Many may think that it makes no difference in the database, but it does! And not only for…
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answers2309
viewsDifference in Indice Unique and Unique Constraint usage in Sql Server?
I would like to know the behavior/differences between a Indice Unique and Unique Constraints to the Sql Server ? Many may think that it makes no difference in the database, but it does! And not only…
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answer584
viewsDifference in Indice Unique and Unique Constraint usage in Informix?
I would like to know the behavior/differences between a Indice Unique and Unique Constraints to the Informix ?
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answers626
viewsHow does php guarantee a single session_id?
Which algorithm used to secure a single session_id()? I wanted to know what the creation and verification is like to ensure that such an ID does not collide with an existing one? I need to create…
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answer67
viewsIs it possible not to allow duplicity in a combination of 2 columns or more?
I know that SQL Server has the Primary Keys and start not to allow duplicate records, but it is possible to do this through 2 columns or more? As an example, I have a table with column, house and…
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answer2019
viewsCould you add a UNIQUE field that accepts nulls?
I can create a field that accepts nulls and say it is unique? This table of mine, the CRM indicates that he is a doctor and not a normal person, he has to be unique, but has to allow nulls. This…
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answer195
viewsHow to make is_unique two fields?
I’m in a need I don’t know how to accomplish. Well, my problem is: I have a field is_unique which refers to two fields of my BD, the IDENTIFIER and the PLAN. I would like to know how to carry out…
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answer563
viewsHow to check if a name is in the database?
I want to check if a name exists in the database; if there is no registration. Using the code below I can register several users with the same name. php. $user = $_POST['user']; $pass =…
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answer128
viewsPrint colorful icone
Good Morning, I have an icon on the red HTML page: <i class="fa fa-circle fa-2x text-danger"></i> When I have it printed, it turns black and white. There is a way to change this with…
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answers2140
viewsHow to add a "Constraint Unique" to a column without deleting the table or column
This is the example table create table usuario( id serial primary key not null, nome varchar(100), email varchar(100), login varchar(100), senha varchar(100), tipo varchar(50), status varchar(30) )…
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answer65
viewsAccess Database, Record Duplication
In a BD Access with fields ID (Automatic Numbering), EMPLOYEE, DATE, QUANTITY, the data is collected daily (in a single message) via Outlook. So, is it possible to prevent the same employee from…
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answer294
viewsID sequence advances +1 during error [Postgresql]
I have the following table in the database in postgresql The fact is that the column Description is unique_key so for testing issues I decided to insert some records with the repeated values in the…
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answer36
viewsValidation Unique PUT and POST UNIQUE in REQUEST Laravel
I have a problem validating the Unique field. My problem before was q if I was going to update the value I didn’t edit, because I was accusing q the value was Japanese, I solved it, but now it…