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23 Απρ 2024 · You can create a check constraint in a table to specify the data values that are acceptable in one or more columns in SQL Server by using SQL Server Management Studio or Transact-SQL. For more information on adding column constraints, see ALTER TABLE column_constraint .
SQL CHECK Constraint. The CHECK constraint is used to limit the value range that can be placed in a column. If you define a CHECK constraint on a column it will allow only certain values for this column.
The CHECK constraint allows you to specify the values in a column that must satisfy a Boolean expression. For example, to require positive unit prices, you can use: CREATE SCHEMA test; GO. CREATE TABLE test.products( product_id INT IDENTITY PRIMARY KEY, product_name VARCHAR (255) NOT NULL, unit_price DEC (10, 2) CHECK (unit_price > 0) );
15 Οκτ 2021 · The check constraints are the rule or set of rules that help to check the inserted (or updated) data values to tables based on a certain condition. So that, we can validate the newly inserted data values based on a specified rule before accepting them to the table.
A CHECK constraint is an integrity constraint in SQL that allows you to specify that a value in a column or set of columns must satisfy a Boolean expression. You can define a CHECK constraint on a single column or the whole table.
In SQL Server, a check constraint is used to specify the limitation on the values of a column when inserting or updating. For example, use check constraint if a column required a date value in specific range, or a value must be in some specific format e.g. value in the zip_code column must be of 5 digits.
2 Ιαν 2024 · You can create a CHECK constraint with any logical (Boolean) expression that returns TRUE or FALSE based on the logical operators. For example, the range of values for a salary column can be limited by creating a CHECK constraint that allows for only data that ranges from $15,000 through $100,000.
