Microsoft SQL Server Database Quiz Questions

A foreign key is used to establish a link between the data in two tables, not to uniquely identify rows in a table.

The foreign key constraint ensures that the value in one table matches a value in another table, maintaining referential integrity.

A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. The foreign key references the primary key of the other table.

Foreign keys can contain NULL values unless they have a NOT NULL constraint. This can happen when a foreign key does not always reference an existing primary key.

A table can indeed have multiple foreign keys, each linking to a primary key in another table.

Foreign key constraints prevent actions that would lead to orphaned records in a related table, thus maintaining referential integrity.

A foreign key must reference an existing primary key value in the parent table to maintain referential integrity.

Whether related rows in a child table are deleted when a parent row is deleted depends on the ON DELETE action specified in the foreign key constraint (e.g., CASCADE, SET NULL).

Foreign keys typically reference primary key columns in the parent table, but they can also reference unique constraints in some databases.

Foreign keys are used to ensure that relationships between tables remain consistent, thus maintaining data integrity.

The SQL standard does require support for foreign key constraints to ensure referential integrity, although implementation can vary between databases.

Foreign key constraints can be added to existing tables using the ALTER TABLE statement.

A foreign key can reference a column in the same table, which is often used in hierarchical or self-referencing relationships.

Foreign keys can have duplicate values in the child table, as they are not required to be unique like primary keys.

Foreign keys can reference columns with unique constraints in the parent table, not just primary key columns.

A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. The foreign key references the primary key of the other table.

The primary purpose of a foreign key is to maintain referential integrity between two related tables.

The FOREIGN KEY clause is used in the CREATE TABLE and ALTER TABLE statements to create a foreign key.

When a row with a foreign key is deleted in the child table, it has no impact on the parent table. However, deleting a row in the parent table may affect the child table based on the ON DELETE action specified.

The ALTER TABLE command is used to add a foreign key to an existing table.

Foreign keys are used to enforce referential integrity by ensuring that a column or a group of columns in a table match values in a column or a group of columns in another table.

Foreign keys are fields in a table that are primary keys in another table, helping to link the two tables together.

The main advantage of using foreign keys is to ensure data consistency and referential integrity between tables.

The CASCADE option in a foreign key constraint specifies that when a parent row is deleted or updated, the corresponding child rows are automatically deleted or updated.

When the parent row is deleted, the ON DELETE CASCADE option ensures that all related child rows are also deleted.

The FOREIGN KEY keyword is used to enforce referential integrity between two tables.

Foreign keys can contain NULL values unless explicitly disallowed by a NOT NULL constraint.

The ALTER TABLE statement with the DROP CONSTRAINT clause is used to remove a foreign key constraint from a table.

A foreign key constraint can enforce referential integrity by ensuring that values in a child table correspond to values in a parent table.

The default action if no ON DELETE or ON UPDATE action is specified is NO ACTION, which means no automatic changes to the child table.

Foreign keys enforce referential integrity, can contain NULL values unless restricted, and can link tables by referencing primary keys or unique constraints.

Foreign keys can be used to link tables, enforce referential integrity, and be part of a composite key, but they do not have to be unique.

Foreign keys typically reference primary keys but can also reference columns with unique constraints.

The ON UPDATE clause in a foreign key constraint specifies the action to be taken when a referenced row in the parent table is updated.

The SET NULL option ensures that when a referenced row is deleted or updated, the foreign key in the child table is set to NULL.

The FOREIGN KEY clause in SQL Server is used to enforce referential integrity between tables.

The ON UPDATE CASCADE option specifies that when a parent row is updated, the corresponding child rows are also updated.

Foreign key constraints help maintain referential integrity by ensuring that rows in one table reference existing rows in another table.

The ON UPDATE clause is used to define how changes to the foreign key column should propagate to the related rows.

The ON DELETE CASCADE option ensures that child rows are deleted when the referenced row in the parent table is deleted.

The ON DELETE and ON UPDATE clauses in foreign key constraints specify actions that occur when a foreign key relationship is updated or deleted.

Foreign key constraints can be added, modified, and removed using various SQL commands.

Different actions like CASCADE, SET NULL, and RESTRICT can be specified for foreign keys when a referenced row is deleted.

The ALTER TABLE statement is used to enforce actions defined in a foreign key constraint.

Valid options for handling foreign key constraints in SQL Server include CASCADE, SET NULL, and NO ACTION.