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SQL 2022-03-17 08:10:20
sql constarint
It creates a new constraint on an existing table, which is used to specify rules for any data in the table. Example: Adds a new PRIMARY KEY constraint named ‘user’ on columns ID and SURNAME. ALTER TABLE users ADD CONSTRAINT user PRIMARY KEY (I... Add solution -
SQL 2021-11-19 02:00:09
what are all the different types of indexes in sql
"There are two types of Indexes in SQL Server 1. Clustered Index A clustered index defines the order in which data is physically stored in a table. Table data can be sorted in only way, therefore, there can be only one clustered index per table.... Add solution -
SQL 2021-10-21 00:55:09
difference between unique vs primary key in sql
What is the difference between UNIQUE and PRIMARY KEY constraints? There should be only one PRIMARY KEY in a table whereas there can be any number of UNIQUE Keys. PRIMARY KEY doesn’t allow NULL values whereas Unique key allows NULL values. Add solution -
SQL 2021-10-02 11:04:04
SQL > Manipulação de Tabelas > Constraint
Pode colocar restrições para limitar o tipo de dados a introduzir numa tabela. Essas restrições podem ser especificadas quando a tabela for primeiro criada através da instrução CREATE TABLE ou após ... Add solution