databasussybaka

what is primary key

• an attribute or smallest set of attributes in a table where no tuple has the same value.

• a unique identifier for a table. It is a special case of a candidate key.

• a candidate key that is an alternative to the primary key.

• a set of attributes in one table that refer to the primary key in another table.

what is a candidate key

• a key that is an alternative to the primary key.

• an attribute or smallest set of attributes in a table where no tuple has the same value.

• a unique identifier for a table. It is a special case of a key.

• a set of attributes in one table that refer to the primary key in another table.

what is a secondary key

• a set of attributes in one table that refer to the primary key in another table.

• a candidate key that is an alternative to the primary key.

• a unique identifier for a table. It is a special case of a candidate key.

• an attribute or smallest set of attributes in a table where no tuple has the same value.

what is a foreign key

• a unique identifier for a table. It is a special case of a candidate key.

• a set of attributes in one table that refer to the primary key in another table.

• a candidate key that is an alternative to the primary key.

• an attribute or smallest set of attributes in a table where no tuple has the same value.

what is a composite key

• a set of attributes in one table that refer to the primary key in another table.

• a set of attributes that form a primary key to provide a unique identifier for a table.

• a candidate key that is an alternative to the primary key.

• a unique identifier for a table. It is a special case of a candidate key.

what is normalisation

• making things normal

• the process of organising data to be stored in a database into two or more tables

• putting select groups in concentration camps

• the process of organising data to be stored in a database into one table

which one is 2NF

• 
• 
• 

what is a field

• an instance of an entity in a table.

• a row in a table in a database.

• a column in a table in a database.

• anything that can have data stored about it, for example, a person, place, event, thing.

what is a record

• a composite data type allowing different kinds of info in the record type

• a data structure built from one or more columns in a database table to speed up searching for data.

• anything that can have data stored about it, for example, a person, place, event, thing.

• a row in a table in a database.

draw an E-R diagram with tables 'STUDENT', 'CLASS', 'THEIR MOMS'