jet/wiki/UPDATE.md

UPDATE changes the values of the specified columns in all rows that satisfy the condition. More about UPDATE statement in PostgreSQL: https://www.postgresql.org/docs/11/sql-update.html

Following clauses are supported

• UPDATE(columns...) - list of columns to update
• SET(values...) - list of values for columns
• MODEL(model) - list of values for columns will be extracted from model object
• WHERE(condition) - row condition to update
• RETURNING(columns...) - list of columns to return as statement result

This list might be extended with feature Jet releases.

Example

// replace all Bing links with Yahoo
updateStmt := Link.
    UPDATE(Link.Name, Link.URL).
    SET("Yahoo", "http://yahoo.com").
    WHERE(Link.Name.EQ(String("Bing")))

Debug sql of above statement:

UPDATE test_sample.link          -- 'test_sample' is name of the schema
SET (name, url) = ('Bong', 'http://bong.com')
WHERE link.name = 'Bing';

Short-hand notation to extract model data for column values:

yahoo := model.Link{
    URL:  "http://www.yahoo.com",
    Name: "Yahoo",
}

updateStmt := Link.
    UPDATE(Link.Name, Link.URL, Link.Description).
    MODEL(yahoo).
    WHERE(Link.Name.EQ(String("Bing")))

Link.Name, Link.URL, Link.Description - can be replaced with Link.MutableColumns. All columns minus primary key columns. Primary key columns are not updated usually.

updateStmt := Link.
    UPDATE(Link.MutableColumns).
    MODEL(yahoo).
    WHERE(Link.Name.EQ(String("Bing")))

Execute statement

To execute update statement and get sql.Result:

res, err := updateStmt.Exec(db)

To execute update statement and return row records updated, statement has to have RETURNING clause:

updateStmt := Link.
    UPDATE(Link.MutableColumns).
    MODEL(yahoo).
    WHERE(Link.Name.EQ(String("Bing"))).
    RETURNING(Link.AllColumns)
    
dest := []model.Link{}

err := updateStmt.Query(db, &dest)
    

Use ExecContext and QueryContext to provide context object to execution.

Update example SQL table:

CREATE TABLE IF NOT EXISTS link (
    id serial PRIMARY KEY,
    url VARCHAR (255) NOT NULL,
    name VARCHAR (255) NOT NULL,
    description VARCHAR (255)
);