napkin-0.5.9
Copyright(c) Soostone Inc 2020
LicenseAllRightsReserved
Stabilityexperimental
PortabilityPOSIX
Safe HaskellNone
LanguageHaskell2010

Napkin.Untyped.Utils

Description

 
Synopsis

Documentation

combineTablesLeft #

Arguments

:: DefinedRelation 
-> [(DefinedRelation, Ref Relation -> Ref Relation -> SExp)]

Table definitions and primary keys each shares with the first table in list

-> Q () 

Combine multiple tables/queries that were defined in napkin that share a common set of primary keys via a chain of left joins.

columnsToRows #

Arguments

:: DefinedRelation 
-> [String]

Groups, keep these intact on each row

-> Query 

Transfroms columns into separate rows, per given partition

unionTables :: [DefinedRelation] -> Query #

Combine all tables into one assuming if the field names are the same, their types will just work out. Fill missing columns with NULL on a per-table basis.

unionWithSchema :: [(Relation, Fields Field)] -> Query #

Unify schemas and join given relations under a single UNION query.

unifySchemas :: [(Relation, Fields Field)] -> [Query] #

Given relations' and their known schema, whether it's a Query or a table reference, union them in a way that works out the missing columns in each and even unifies mis-matching types to a common denominator.

castToField :: Field -> SExp -> SExp #

Cast expression bsaed on a desired type from the sql-schema library.

filterFields :: (Ref t -> Bool) -> Query -> Query #

Only keep selected fields in Query that pass the predicate.

whitelistFields :: Foldable t1 => t1 Regex -> Ref t -> Bool #

Keep any field that matches any of the given regexes. Can use this to construct the predicate in filterFields

longToWideFormat :: (SExp -> SExp) -> [Alias SExp] -> [(SExp, SExp, Ref SExp)] -> Query -> Query #

Convert a "long" query to "wide" by aggregating/matching over certain SExps.

longToWideFormatSimple :: (SExp -> SExp) -> [Alias SExp] -> [(SExp, SExp)] -> Ref SExp -> SExp -> Query -> Query #

A long-to-wide query transformer which matches using equality

simpleValueAsColumnName :: Text -> Value -> Ref SExp #

A basic means of generating new column names from

splitUnions :: Foldable t => Int -> t Query -> [Query] #

Given a list of queries that may contain any number of top level UNIONs, chunk them into queries where each contains at most N unions.

Useful for reducing/capping the size of each top level query so they can be sent individually to the database.