ch 4

Views

• A view provides access to a subset of fields and records in one or more tables.
• A view provides a light blanket of security by limiting access to specific data.
• A view automatically shows up-to-date information when it is executed.
• Access does not support the SQL CREATE VIEW statement because queries function as views.

Indexes

• The primary purpose of creating an index is to improve the speed by which data is searched and presented.

Null Values

• A null value represents an intentional nothing.
• A null value is not the same as a zero-length string (“”) or a space or tab character.

Referential Integrity

• Enforcing referential integrity on a one-to-many relationship prevents deleting a record in the parent table that has a matching record in a child table.
• Enforcing referential integrity on a one-to-many relationship does not prevent incorrect entry into a primary key field or value entry into a foreign key field that doesn’t have a match in the table that contains the primary key field.

Relationships

• In a one-to-many relationship, the table on the “one” side is also called the parent or left table.
• In a one-to-many relationship, the table on the “many” side may have orphan records, especially if referential integrity is not enforced.

Joins and Queries

• RIGHT JOINS in SQL are helpful to find orphan records.
• When two tables are joined in an Access query, the default join type is INNER.

Database Documenter

• The Database Documenter is a feature of Access used to create a report on the metadata about tables and queries.

Stored Procedures and Triggers

• Stored procedures differ from triggers in that stored procedures are usually run intentionally by users, whereas triggers are generally run automatically by processes.
• Data macros mimic the feature of relational database management system triggers.

Field Properties

• The Validation Rule field property is used to set data integrity rules on a single field.