Searching

Searching a table always returns a new Dataset with the matching subset of the original dataset. You can use the usual comparison operators to search. Search via regular expressions is supported with the like operator, and it is possible to check for the existence of a data field by comparing it to null.

A field name can be dotted to address sub-fields. If, for example, the search should check the field zip of an address field, use the notation address.zip.

Here is an example for such a data record:

{
    "name" : "John Smith",
    "age": 44,
    "address" : {
        "street" : "1234 Wonder St",
        "zip" : 94016,
        "city" : "San Jose",
        "state" : "CA"
    }
}

There are two search functions:

function where (string $field, string $op, string $value) : Dataset;
function orWhere (string $field, string $op, string $value) : Dataset;

Both functions return a new Dataset containing the search result, so these calls can be chained.

To access the result of a search, use the dataset’s fetch() method.

The $op parameter is the operator to use, which can be one of = (or ==), !=, <, >, <=, >=, or like, and the $value field is the value to compare against.

The like operator expects the value to be a regular expression string. Here is an example of finding all records whose city starts with “San “:

$set = $table->where('address.city' 'like', '/^San /');

Here is an example of a chained call, finding all NY residents with an age > 65:

$set = $table->where('address.state' '=', 'NY')->orWhere('age' '>', 65);

The orWhere() method combines its search with the search result of the parent dataset. This call, for example, finds all residents of NY or TX:

$set = $table->where('address.state' '=', 'NY')->orWhere('address.state' '=', 'TX');

Selecting

Often, it is more interesting to see the field values instead of the entire record. Use the select() function to select a data field (again, dots are permitted). If you, for example, juzst want a list of Zip codes, use this call:

$set = $table->select('address.zip');

A subsequent call to fetch() returns an array of Zip codes.