Statement Templates

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Note

• Templates are injected directly into generated SQL. Evaluate injection risk or choose another approach such as JdbcTemplate.

When using the Fluent API, statement templates shape the generated SQL fragments.

Example: for MySQL tables with point columns, templates let you wrap reads/writes with PointFromText and AsText.

例：表

create table user_points
(
    id    int auto_increment primary key,
    point point,
    text  varchar(50)
);

Example: mapping

@Table("user_points")
public class UserPoints {
    private Integer id;

    @Column(selectTemplate   = "AsText(point)",  // Generates select AsText(point) as point
            insertTemplate   = "GeomFromText(?)",// Generates insert ... values (GeomFromText(?))
            setValueTemplate = "GeomFromText(?)",// Generates update ... set point = GeomFromText(?)
            whereColTemplate = "AsText(point)"   // Generates ... where AsText(point) = ?
    )
    private String point;
}

Example: INSERT and generated SQL

UserPoints point = new UserPoints();
point.setId(1);
point.setPoint("point(1,2)");

LambdaTemplate lambda = ...
int result = lambda.insert(UserPoints.class)
                   .applyEntity(point);
                   .executeSumResult();

// SQL: INSERT INTO user_points (id, point) VALUES (?, GeomFromText(?))

Example: UPDATE and generated SQL

LambdaTemplate lambda = ...
int result = lambda.update(UserPoints.class)
                   .eq(UserPoints::getId, 1)                     // 匹配条件
                   .updateTo(UserPoints::getPoint, "point(1,2)") // 更新字段
                   .doUpdate();

// SQL: UPDATE user_points SET point = GeomFromText(?) WHERE ( id = ? )

Example: DELETE and generated SQL

LambdaTemplate lambda = ...
int result = lambda.delete(User.class)
                   .eq(UserPoints::getPoint, "point(1,2)") // 匹配条件
                   .doDelete();

// SQL: DELETE FROM user_points WHERE ( AsText(point) = ? )

Template attributes

Attribute	Description
selectTemplate	Column expression in SELECT. Empty = column name.
insertTemplate	Argument expression in INSERT. Default ?.
setValueTemplate	Argument expression in UPDATE SET. Default ?.
whereColTemplate	Column expression in WHERE (update/delete). Empty = name.
whereValueTemplate	Argument expression in WHERE (update/delete). Default ?.
orderByColTemplate	Column expression in ORDER BY. Empty = column name.