Struct MySqlProjectionGenerator 

pub struct MySqlProjectionGenerator { /* private fields */ }

MySQL SQL projection generator.

MySQL uses JSON_OBJECT() for field projection, similar to PostgreSQL’s jsonb_build_object(). Generates efficient SQL that projects only requested JSON fields.

Example

use fraiseql_db::projection_generator::MySqlProjectionGenerator;

let generator = MySqlProjectionGenerator::new();
let fields = vec!["id".to_string(), "name".to_string()];
let sql = generator.generate_projection_sql(&fields).unwrap();
assert!(sql.contains("JSON_OBJECT"));

Implementations

impl MySqlProjectionGenerator

pub fn new() -> Self

Create new MySQL projection generator with default JSON column name.

Default JSON column: “data”

pub fn with_column(json_column: &str) -> Self

Create projection generator with custom JSON column name.

Arguments

• json_column - Name of the JSON column in the database table

pub fn generate_projection_sql(&self, fields: &[String]) -> Result<String>

Generate MySQL projection SQL for specified fields.

Generates a JSON_OBJECT() call that selects only the requested fields from the JSON column.

Arguments

• fields - JSON field names to project

Returns

SQL fragment that can be used in a SELECT clause

Errors

Returns FraiseQLError::Validation if any field name cannot be safely projected.

Trait Implementations

impl Default for MySqlProjectionGenerator

fn default() -> Self

Returns the “default value” for a type.