RelationProxy

A structure proxying to the actual Postgres table.

Allows short and readable querying, returning actual records or arrays of them. first, last, and all will be cached if appropriate, the rest will execute a query whenever a result is needed. Most functions return a reference to the same object, allowing you to chain them. Builder pattern, really.

Can be implicitly converted to an array of the requested structure.

Mostly meant to be used with RelationMixin, but can be used manually.

Constructors

this this(Connection connection): Basic constructor. RelationProxy requires a connection to operate on.

Alias This

all

Members

Aliases

and alias and = where: Convenience alias, allows us to do proxy.where(..).and(...)

Functions

count long count(string col): Selects the count of records with current filters. Default is *, but any column can be specified as a parameter. The column name is not further escaped.
find Nullable!T find(U param): Same as above, but always searches by the primary key
findBy Nullable!T findBy(U[string] filters): Finds a single record matching the filters. Equivalent to where(...).first.
insert T insert(T record): Inserts a new record, takes the record as a reference in order to update its PK value. Does not update any other values.
reload auto ref reload(): Reloads the content with existing filters.
remove auto remove(Tpk id): Removes a single record, filtering it by the primary key's value.
removeAll auto removeAll(): Simply deletes all the records matching the filters.
save bool save(T record): Updates the given record in the DB with all the current values.
update auto update(Tpk id, U[string] values): Undocumented in source. Be warned that the author may not have intended to support it.
updateAll auto updateAll(U[string] updates): Update all the records matching filters to new values from the AA.
where auto ref where(U[string] filters): Specifies filters according to the given AA. Filters will be joined with AND.
where auto ref where(string filter, U params): Same as above, but allowing you to specify a completely custom filter. The supplied string will be wrapped in (), can be called multiple times to specify multiple filters.

Properties

all T[] all [@property getter]: Returns the actual content, executing the query if data has not yet been fetched from the database.
dup RelationProxy!T dup [@property getter]: Makes a copy of just the filters, not any content;
first Nullable!T first [@property getter]: Fetches the first record matching the filters.
last string last [@property setter]: Same as first, but defaults to desceding order, giving you the last match.
or auto ref or [@property getter]: Inserts an OR seperator between the filters.
toString string toString [@property getter]: A basic toString implementation, mostly here to prevent querying when the object is implicitly converted to a string.

Examples

struct User
{
   // provides where, find, findBy, etc on the User struct
   mixin RelationMixin;

   @PK @serial int id      string username;
}

auto user1 = User.where(["id": 1]).first;
// Or better yet. Search directly by PK
auto betterUser1 = User.find(1);
// Delete some users
long nDeleted = User.where("username LIKE 'somethi%'").removeAll();