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The following example of a SELECT query returns a list of expensive books. The query retrieves all rows from the Book table in which the price column contains a value greater than 100.00. The result is sorted in ascending order by title. The asterisk (*) in the select list indicates that all columns of the Book table should be included in the ...
This list includes SQL reserved words – aka SQL reserved keywords, [1] [2] as the SQL:2023 specifies and some RDBMSs have added. Reserved words in SQL and related products In SQL:2023 [ 3 ]
In the above example, the application might supply the values "bike" for the first parameter and "10900" for the second parameter, and then later the values "shoes" and "7400". The alternative to a prepared statement is calling SQL directly from the application source code in a way that combines code and data.
Referential integrity is a property of data stating that all its references are valid. In the context of relational databases, it requires that if a value of one attribute (column) of a relation (table) references a value of another attribute (either in the same or a different relation), then the referenced value must exist. [1]
assign a predicate IRI to each column; assign an rdf:type predicate for each row, linking it to an RDFS class IRI corresponding to the table; for each column that is neither part of a primary or foreign key, construct a triple containing the primary key IRI as the subject, the column IRI as the predicate and the column's value as the object.
In SQL, the unique keys have a UNIQUE constraint assigned to them in order to prevent duplicates (a duplicate entry is not valid in a unique column). Alternate keys may be used like the primary key when doing a single-table select or when filtering in a where clause, but are not typically used to join multiple tables.
Here, width specifies the width of the columns, and determines dynamically the number of columns based on screen width; more columns will be shown on wider displays. If |colwidth= is not specified, the default width of 30em will be used. This template uses CSS3 multiple-column layout, which is not supported by all web browsers.
Creates a heading for table reference columns. Template parameters [Edit template data] Parameter Description Type Status multi multi plural Specifies whether the column can contain multiple references per row and changes the texts to plural forms accordingly. Default yes Boolean suggested The above documentation is transcluded from Template:Reference column heading/doc. (edit | history ...