How are column constraints and table constraints the same?

Column constraints and table constraints have the same function; the difference is in where you specify them. Table constraints allow you to specify more than one column in a PRIMARY KEY, UNIQUE, CHECK, or FOREIGN KEY constraint definition.
Similarly, can you use the same column more than once in a constraint?
For a table-level foreign key constraint in which you specify the columns in the table that make up the constraint, you cannot use the same column more than once.
Furthermore, how is column constraint defined in ALTER TABLE? ALTER TABLE column_constraint (Transact-SQL) Specifies the properties of a PRIMARY KEY, FOREIGN KEY, UNIQUE, or CHECK constraint that is part of a new column definition added to a table by using ALTER TABLE.
In addition, why are constraints applied on a table level?
This ensures the accuracy and reliability of the data in the database. Constraints could be either on a column level or a table level. The column level constraints are applied only to one column, whereas the table level constraints are applied to the whole table.
In fact, can a check constraint be specified in a table definition?
If a check constraint is specified as part of a column-definition, a column reference can only be made to the same column. Check constraints specified as part of a table definition can have column references identifying columns previously defined in the CREATE TABLE statement.

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How are schedule constraints related to resource constraints?

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What's the difference between a column and a column?

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Why is my column null and my column = null?

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Is the spinal column the same as the vertebral column?

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