Primary keys are defined in the ANSI SQL Standard, through the PRIMARY KEY constraint. The syntax to add such a constraint to an existing table is defined in SQL:2003 as follows:[2] ...
Primary Key The central item or column within an RDBMS that contains a unique value for each record in the database, such as the unique number assigned to each parcel within a country.
Projection See Map Projection
Q ...
primary keyOne or more attributes whose values uniquely identify a row in a database table. See also foreign key.
See Also: primary key
[computing] In a relational database, any key that can be used as the primary key in a table.
For example, a table will not be given a foreign key value that does not exist as a primary key in another table. region A coverage feature class used to represent a spatial feature as one or more polygons.
A key that can be used to uniquely identify a row in a table is called a primary key. Keys are commonly used to join or combine data from two or more tables.
sql:26: NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "states_pkey" for table "states"
CREATE TABLE
psql:states.sql:27: ERROR: function addgeometrycolu mn(unknown, unknown, unknown, unknown, unknown, integer) does not exist ...
feature labels and DBMS primary keys. This coupling of spatial features with an attribute record is usually maintained by an internal number assigned by the GIS software.
Do not use them as the primary key. The reason is very simple. If you use a smart key like SBL number and you have to change the number, you run the risk of losing the connection to all other related tables that key on the SBL number.
CREATE TABLE test ( id serial NOT NULL, mytime timestamp DEFAULT now(), text varchar, wkb_geometry geometry, CONSTRAINT test_pkey PRIMARY KEY (id) ) WITHOUT OIDS; # insert value INSERT INTO test (text, wkb_geometry) VALUES ('Name', ...
Recall that the keystone concept is an Analysis Frame of grid cells that provides for tracking the continuous spatial distributions of mapped variables and serves as the primary key for linking spatial and non-spatial data sets.
In the ADL Web prototype, we have implemented a large gazetteer, of about 5 million entries (a gazetteer is defined as an index linking place-names to geographic locations, with place-names as the primary key; ...
- In both cases the attributes were linked to the objects by primary keys; ...
Any data element in a relationship can be found by knowing the table name, the attribute (column) name, and the value of the primary key.
Collection of tables that are logically associated to each other by shared common attributes. Entering the table name, attribute name, and the value of the primary key, any data element or set of elements can be retrieved.
structuring data as collections of tables that are logically associated to each other by shared attributes. Any data element can be found in a relation by knowing the name of the table, the attribute (column) name, and the value of the primary key.
location, which is represented by a spatial point, might include an engine bay that accommodates a certain number of engines, crews, dozer pads, and so on. These attributes are stored in a database and relate to the feature using a primary key ...
If columns are made longer after database setup is used and those lengths are longer than what the database and driver support, an ODBC error will likely occur.
New primary key added to BUD_CATALOG table for improved performance ...
Each set has elements that can be uniquely defined by a primary key. A table (relation) stores all records for a set. Each record in a table has the same columns for attribute values.
 See also: Database, Information, Attribute, Record, Relation
  
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