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pgCondition

OUT OF DATE

This documentation page is out of date! We've not had time to update it correctly yet, but here's an incredibly quick and poor overview... (Please do send a PR to update this page if you want to help!)

A PgCondition instance is a "modifier" typically acquired from a runtime query builder via the queryBuilder.whereBuilder() (for WHERE clause) or queryBuilder.havingBuilder() (for HAVING clause), or from another PgCondition instance. It's used to build up complex conditions on a layer by layer basis, which is useful for "filter" plugins.

A query builder is something that you manipulate at runtime (not plantime) but you need to register your synchronous callback for it at plantime, e.g. via $pgSelect.apply($myCb) where $myCb is a step representing a callback function, for example const $myCb = lambda($foo, (foo) => queryBuilder => { doSomethingWith(queryBuilder, foo) }).

This "Modifier" class (not a Step) is commonly acquired from $pgSelect.wherePlan(), $pgSelect.havingPlan(), or similar methods. It's useful for building up a condition (WHERE or HAVING clause) bit by bit, and is used at runtime.

tip

This is an advanced class, you probably will never use it unless you're building advanced filtering capabilities into your GraphQL schema.

pgConditions are created with a parent (a PgConditionCapableParent - typically another PgCondition, a PgSelect, or similar) and a mode:

  • PASS_THRU - passes conditions directly up to the parent
  • AND - combines conditions with AND and passes the result up to the parent
  • OR - combines the conditions with OR and passes the result up to the parent
  • NOT - combines the conditions with AND, groups them together and does a NOT of the result, which is then passed up to the parent
  • EXISTS - builds an EXISTS(...) expression utilising the conditions and passes it up to the parent

$pgCondition.orPlan()​

Returns a child pgCondition in OR mode.

$pgCondition.andPlan()​

Returns a child pgCondition in AND mode.

$pgCondition.notPlan()​

Returns a child pgCondition in NOT mode.

$pgCondition.existsPlan(options)​

Returns a child pgCondition in EXISTS mode with the given options.

$pgCondition.where(condition)​

Adds condition to the list of conditions. Cannot be used in "having" mode.

$pgCondition.having(condition)​

Adds condition to the list of conditions. Cannot be used unless in "having" mode.

sqlValueWithCodec(value, codec)​

Converts value (arbitrary value) according to the rules of codec (a PostgreSQL codec indicating the expected type) and returns an SQL expression suitable to be embedded in a larger query.