Primary Key
A unique identifier for each record in a GIS attribute table, essential for data integration and relational database management (inferred from standard GIS usage).
What does the term Primary Key mean?
A primary key is a special identification for every record (or row) in a table used in database administration and GIS. It guarantees that each element in a dataset can be uniquely recognized and cited.
Important Features of a Primary Key:
Uniqueness: No primary key value can be shared by two records.
Non-null: A primary key cannot be null or empty; it must always contain a value.
Integrity: By avoiding duplicate entries and facilitating trustworthy links between tables, it preserves data integrity.
Related Keywords
In SQL, a primary key is a field, or group of columns, that gives each record in a table a unique identity. No two rows can have the same primary key value, and it cannot be left empty, as it guarantees uniqueness and non-null values. It is usually used to create relationships between tables and maintain data integrity.
Each record in a table in a database is uniquely identified by its primary key. The StudentID column, for instance, can be used as the primary key in a Students table to guarantee that every student has a distinct ID and avoid duplicate records.
Each record in a database table is uniquely identified by a primary key, which makes sure that no two rows have the same value in that column. In order to establish a connection between two tables and maintain referential integrity, a foreign key is a column in one table that makes reference to the primary key in another. They work together to keep relational data organized and consistent.
Each record in a table is uniquely identified by a Primary Key Constraint in SQL. It guarantees that only distinct and non-null values are present in the column (or set of columns) designated as the primary key. One primary key per table helps preserve data integrity and facilitates effective data retrieval.