Function register_system_functions

src/functions/system_functions.rs:5–468

Register PostgreSQL system information functions

(conn: &Connection)

/// Register PostgreSQL system information functions
pub fn register_system_functions(conn: &Connection) -> Result<()> {
    debug!("Registering system functions");
    
    // version() - Returns PostgreSQL version string
    conn.create_scalar_function(
        "version",
        0,
        FunctionFlags::SQLITE_UTF8 | FunctionFlags::SQLITE_DETERMINISTIC,
        |_ctx| {
            // Return a PostgreSQL-compatible version string
            // This format is what SQLAlchemy expects to parse
            Ok(format!("PostgreSQL 16.0 (pgsqlite {}) on x86_64-pc-linux-gnu, compiled by rustc, 64-bit",
                env!("CARGO_PKG_VERSION")))
        },
    )?;
    
    // current_database() - Returns the current database name
    conn.create_scalar_function(
        "current_database",
        0,
        FunctionFlags::SQLITE_UTF8 | FunctionFlags::SQLITE_DETERMINISTIC,
        |_ctx| {
            // In SQLite, we'll return "main" as the database name
            Ok("main".to_string())
        },
    )?;
    
    // current_schema() - Returns the current schema name
    conn.create_scalar_function(
        "current_schema",
        0,
        FunctionFlags::SQLITE_UTF8 | FunctionFlags::SQLITE_DETERMINISTIC,
        |_ctx| {
            // SQLite doesn't have schemas, return "public" for PostgreSQL compatibility
            Ok("public".to_string())
        },
    )?;
    
    // current_schemas(include_implicit) - Returns array of schemas in search path
    conn.create_scalar_function(
        "current_schemas",
        1,
        FunctionFlags::SQLITE_UTF8 | FunctionFlags::SQLITE_DETERMINISTIC,
        |ctx| {
            let include_implicit: bool = ctx.get(0)?;
            if include_implicit {
                // Include system schemas
                Ok(r#"["pg_catalog","public"]"#.to_string())
            } else {
                // Just user schemas
                Ok(r#"["public"]"#.to_string())
            }
        },
    )?;
    
    // current_user() - Returns the current user name
    conn.create_scalar_function(
        "current_user",