In the relational model of databases, a primary key is a designated attribute (column) that can reliably identify and distinguish between each individual...

but only one of them is used as the primary key of the relation. The remaining candidate keys are called unique keys because they can uniquely identify...

primary key firstName + lastName for students is a composite key. Relational database Alternate key Candidate key Foreign key Primary key Unique key Superkey...

A foreign key is a set of attributes in a table that refers to the primary key of another table, linking these two tables. In the context of relational...

Industry and Security (BIS). It was already known that Microsoft used two keys, a primary and a spare, either of which can create valid signatures. Upon releasing...

world and the primary key of the database. In this case the surrogate may be used as a primary key, resulting in the term surrogate key. In a temporal...

have a unique primary key (PK) for each row in a table. When a new row is written to the table, a new unique value for the primary key is generated; this...

the relational model has a primary key which uniquely identifies a row. In our example, the primary key is a composite key of {Title, Format} (indicated...

attributes. Specific candidate keys are sometimes called primary keys, secondary keys or alternate keys. The columns in a candidate key are called prime attributes...

are generally assigned a surrogate key to ensure each row can be uniquely identified. This key is a simple primary key. Dimension tables usually have a...

foreign key can only contain either null values or values from a parent table's primary key or a candidate key. In other words, when a foreign key value...

concerns the concept of a primary key. Entity integrity is an integrity rule which states that every table must have a primary key and that the column or...

between entities is implemented by storing the primary key of one entity as a pointer or "foreign key" in the table of another entity. There is a tradition...

first asserts the primary key of the piece, that is, the tonic. The second section moves to a different key, establishes that key firmly, arriving ultimately...

concerned with ensuring that each row of a table has a unique and non-null primary key value; this is the same as saying that each row in a table represents...

[column name] [data type] {NULL | NOT NULL} {column options} Primary key definition: PRIMARY KEY ( [comma separated column list] ) Constraints: {CONSTRAINT}...

dbm manages associative arrays of arbitrary data by use of a single key (a primary key). Modern implementations include sdbm, GNU dbm, and Berkeley DB. Although...

Each row is identified by a primary key and contains columns. The first component of a table's primary key is the partition key; within a partition, rows...

used to police database constraints, such as UNIQUE, EXCLUSION, PRIMARY KEY and FOREIGN KEY. An index may be declared as UNIQUE, which creates an implicit...

foreign key is a column in another table that refers to a primary key. Keys can comprise several columns, in which case they are composite keys. In many...

column, which provides faster access. If a table includes an INTEGER PRIMARY KEY column, SQLite will typically optimize it by treating it as an alias...

California a key player in 2008 – CNN.com". Cnn.com. Retrieved September 15, 2008. "Newhouse News Service – Giuliani Eyes Winner-Take-All Primaries". Newhouse...

it must use a foreign key in conjunction with its attributes to create a primary key. The foreign key is typically a primary key of an entity it is related...

"key fields". A "primary key" assigns a field to its "special order table". For example, the "Doctor Last Name" field might be assigned as a primary key...

A natural key (also known as business key or domain key) is a type of unique key in a database formed of attributes that exist and are used in the external...

searches can make queries slower. Many of Amazon's services demanded mostly primary-key reads on their data, and with speed a top priority, putting these pieces...

database invariant is referential integrity, which guarantees the primary key–foreign key relationship. Transactions are often executed concurrently (e.g...

designated as a primary key by which the rows of the table could be uniquely identified; cross-references between tables always used these primary keys, rather...

tables: Department.DepartmentID is the primary key of the Department table, whereas Employee.DepartmentID is a foreign key. Note that in Employee, "Williams"...

rather of the relationship itself. One-to-many often refer to a primary key to foreign key relationship between two tables, where the record in the first...