Element

The Element type is provided as a struct that represents a single row/record in the table, with the following fields:

• tname - name of the table this element belongs to (used for type checking)
• field - hash map that contains all fields of this row (std.StringHashMap(FieldType))
• scheme - link to array used to index fields
• allocator - runs the allocator to duplicate and free arrays.

Function breakdown (Element)

• get
  Purpose: returns the raw value of a field
  Signature:

  get(self: @This(), key: []const u8) ?FieldType

• getAs
  Purpose: returns field value cast to desired type
  Signature:

  getAs(self: @This(), comptime T: type, key: []const u8) ?T

• getIndex/getIndexAs Same as get and getAs but using an index instead of a key

• set
  Purpose: set the raw value of a field
  Signature:

  set(self: *@This(), key: []const u8, value: FieldType) !void

• setAs
  Purpose: sets field value with type conversion
  Signature:

  setAs(self: *@This(), comptime T: type, key: []const u8, value: T) !void

• setIndex/setIndexAs Same as set and setAs but using an index instead of a key

• save / load Save all fields to binary writer Load fields from binary reader

• deinit Purpose: frees hash map memory Signature:

  deinit(self: *@This()) void

Examples

1. Creating and filling Element manually

var scheme = std.ArrayList([]const u8).empty;

var elem = Types.Element{
    .tname = "users",
    .field = std.StringHashMap(Types.FiledType).init(allocator),
    .scheme = &scheme,
    .allocator = allocator,
};
defer elem.deinit();

try elem.setAs(i32, "id", 1);
try elem.setAs([]const u8, "name", "Alice");
try elem.setAs(bool, "active", true);

try users_table.append(elem);

2. Reading values from Element

// continuing from previous code...

if (users_table.get(0)) |row| {
    const id     = row.getAs(i32, "id")     orelse 0;
    const name   = row.getAs([]const u8, "name")   orelse "unknown";
    const active = row.getAs(bool, "active") orelse false;

    std.debug.print("{s} (id {d}, active: {})\n", .{name, id, active});
}