Add QueryTable

src/main/db/query_builder.zig

@@ -4,6 +4,26 @@ const util = @import("util");
 const String = []const u8;
 const comptimePrint = std.fmt.comptimePrint;
 
+pub const QueryTable = struct {
+    Model: type,
+    as: String,
+
+    // Gets a fully qualified field from a literal
+    pub fn field(comptime self: QueryTable, comptime lit: @Type(.EnumLiteral)) String {
+        const f = @as(std.meta.FieldEnum(self.Model), lit);
+        return comptimePrint("{s}.{s}", .{ self.as, @tagName(f) });
+    }
+};
+
+test "QueryTable.field" {
+    const tbl = QueryTable{
+        .Model = struct { id: i32 },
+        .as = "my_type",
+    };
+
+    try std.testing.expectEqualStrings("my_type.id", tbl.field(.id));
+}
+
 // Combines an array/tuple of strings into a single string, with a copy of
 // joiner in between each one
 fn join(comptime vals: []const String, comptime joiner: String) String {
@@ -17,12 +37,14 @@ fn join(comptime vals: []const String, comptime joiner: String) String {
     return result[joiner.len..];
 }
 
+// Stringifies and joins an array of conditions into a single string
 fn joinConditions(comptime cs: []const Condition, comptime joiner: String) String {
     var strs: [cs.len]String = undefined;
     for (cs) |v, i| strs[i] = v.str();
     return join(&strs, joiner);
 }
 
+// Represents a condition in a SQL statement
 pub const Condition = union(enum) {
     const BinaryOp = struct {
         lhs: String,