hows the btec national going..... by the way you cant get away with copy and pasteing....
ps: this is unit 5 of the btec natinal (soft-dev )
Composition is a term that comes from object oriented design. It is a relationship in which a number of parts comprise a whole, and these parts can only be part of one whole. There is no direct translation of this concept to database design, but there are some situations in the database world that represent the concept of composition. Field to record A record is composed of fields and these fields are part of only one record. When the record is removed, the fields are also removed. So, each field has a composition relation with its record. This means that when you store a collection (a comma separated list of names for example) in a database field, this is in fact a composition relationship. Record to record from other table If you want to create a composition relation between records from a table A and records from another table B, where A is the whole and B the parts you must ensure that 1. There is a one-to-many relationship between table A and B. This is done by adding a foreign key to table B. 2. That all part records in B are deleted when the whole record in table A is deleted. This can be done by setting ON DELETE CACADE on the foreign key relationship. 3. That the records in table B don't become part of another composition relationship. But this restriction cannot be enforced by the database to my knowledge.
I accidently deleted my mac mailbox. Everytime I try to open it I get an error message that it can't be opened because it is in the trash.
no
you go to trash can and you recover it
System restore can be useful
Do it yourself. P.S Im a BTEC National Teacher.
Referential dependency in a database refers to the relationship between tables where a foreign key in one table references a primary key in another table. This relationship ensures data integrity and consistency by enforcing constraints that maintain the validity of the data being stored. If a record with a foreign key is deleted or modified, the referential integrity ensures that the associated records in other tables are also updated or deleted to maintain consistency.
Maintaining the integrity of relationships between tables ensures data accuracy and consistency in the database. It helps prevent orphaned records, data anomalies, and ensures referential integrity through foreign key constraints. This allows for efficient data retrieval and manipulation operations.
Database Management Systems ensure consistent data if the database is modeled using proper referential integrity. For example, if a Customer record is deleted from the system, all Orders and Order Items pertaining to that Customer should ideally be cleaned up. Same thing is true for a specific Order. Such logic need not be in the application, instead you can set up database referential integrity rules to perform these cascading actions automatically for you.
There is command in database to delete the data from a table . But what if the data you have deleted was important ? For this there are commands in database system to recover the data. This is what is called data recovery .In database the data can be deleted ,what if the deleted data was important. In that case we use commands like rollback and save point.
Entity integrity ensures that each row in a table is uniquely identifiable by a primary key, while referential integrity ensures that relationships between tables are accurately maintained when data is inserted, updated, or deleted. In essence, entity integrity concerns the uniqueness of data within a table, and referential integrity concerns the relationships between data across different tables.
Referential Integrity is a set of rules that a DBMS (Database management system) follows to ensure that there are matching values in the common field used to create the relationship between related tables and that protects the data in related tables to make sure that data is not accidentally deleted or changed.
ADVANTAGES OF MANUAL DATABASE-It is cheaper-It dosen't consume alot of electricity-You can be exercised-It can't be deleted easilyDISADVANTAGE OF MANUAL DATABASE-It is not that secured-It is harder-It consumes a lot of time
Moral integrity refers to adherence to ethical principles and values in one's actions and decisions. Ennate integrity, on the other hand, refers to an inherent or essential quality that is natural and unchanging. While moral integrity involves conscious choices and behaviors, ennate integrity is more about an innate state or characteristic.
I have deleted my daughters account by emailing customerservice@bellasara.com and writing please remove {account username} from your database. They emailed me back to confirm the deleted account. Hope this helps everyone!
Referential Integrity is a set of rules that a DBMS (Database management system) follows to ensure that there are matching values in the common field used to create the relationship between related tables and that protects the data in related tables to make sure that data is not accidentally deleted or changed.
it means that your profile is deleted or u either got banded from meez