NexusDB Guide > SQL Reference > SQL Statements > Data Statements

NexusDB V3 Manual

UPDATE statement

Update rows of a table.

Syntax

<update statement: searched> ::=

UPDATE [ schema-name. ] table-name [ [ AS ] correlation-name ]

<set clause list> ::=

column-name = <update source> [ { , column-name = <update source> }... ]

<update source> ::=

Usage

The UPDATE statement is used to modify the value of one ore more columns in a selection of rows in the table identified by table-name.

Notes

§	The current database is implicit if schema-name is not specified.

§	The SET clause is a comma-separated list of column assignments. The assigned value can be any valid value expression, including value functions, user-defined functions, scalar subqueries, case expressions, DEFAULT and NULL.

§	Parameters can be used to represent values supplied by the application.

§	The WHERE clause restricts the rows that are updated to those satisfying the search condition. If no WHERE clause is specified, all rows in the table are updated.

Tip: Using a prepared statement with parameters is more efficient than executing a sequence of individual UPDATE statements with explicit values.

Examples

1)	The following example uses literals and value expressions to update studentID 211:

UPDATE students

SET

studentName = firstName || ' ' || lastName,

address = '983 Park Avenue',

city = 'Boston',

state = ( SELECT state FROM students WHERE studentID = 473 ),

zip = '02169'

WHERE studentID = 211

2)	The following example shows a generic UPDATE statement for the students table using parameters to update column values and identify the row:

UPDATE students

SET

studentName = :firstName || ' ' || :lastName,

lastName = :lastName,

firstName = :firstName,

address = :address,

city = :city,

state = :state,

zip = :zip,

gender = :gender

WHERE studentID = :studentID

Conformance

SQL:2003 standard

Core SQL

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