| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Frames.SQL.Beam.Postgres.Query
Description
This module provides certain "canned" queries that would be useful for pulling Postgres rows into a data frame. Also contains a utility function for handling results of join queries.
Synopsis
- type PostgresTable a b = DatabaseSettings Postgres b -> DatabaseEntity Postgres b (TableEntity a)
- type PostgresDB b = DatabaseSettings Postgres b
- type PostgresFilterLambda a s = a (QExpr PgExpressionSyntax s) -> QExpr PgExpressionSyntax s Bool
- type JoinQueryResults a b = [(a Identity, b Identity)]
- allRows :: (Database Postgres b, Table a) => PostgresTable a b -> PostgresDB b -> Q PgSelectSyntax b s (a (QExpr PgExpressionSyntax s))
- allRowsWhere :: (Database Postgres b, Table a) => PostgresTable a b -> PostgresDB b -> PostgresFilterLambda a s -> Q PgSelectSyntax b s (a (QExpr PgExpressionSyntax s))
- join2 :: (Table a, Table b, GenericVinyl (a Identity) a_names a_rs, GenericVinyl (b Identity) b_names b_rs, RecVec (ZipTypes a_names a_rs), RecVec (ZipTypes b_names b_rs)) => JoinQueryResults a b -> FrameRec (ZipTypes a_names a_rs ++ ZipTypes b_names b_rs)
Documentation
type PostgresTable a b = DatabaseSettings Postgres b -> DatabaseEntity Postgres b (TableEntity a) Source #
type PostgresDB b = DatabaseSettings Postgres b Source #
type PostgresFilterLambda a s = a (QExpr PgExpressionSyntax s) -> QExpr PgExpressionSyntax s Bool Source #
type JoinQueryResults a b = [(a Identity, b Identity)] Source #
allRows :: (Database Postgres b, Table a) => PostgresTable a b -> PostgresDB b -> Q PgSelectSyntax b s (a (QExpr PgExpressionSyntax s)) Source #
Helps select all rows from a particular table in a database.
Note that the table and database declaration is present in
the module generated by genBeamSchema, invoked in the end-user code.
Equivalent to SQL: "SELECT * FROM tbl;" when run using an appropriate
run function from the FramesBeam.Streaming module.
allRowsWhere :: (Database Postgres b, Table a) => PostgresTable a b -> PostgresDB b -> PostgresFilterLambda a s -> Q PgSelectSyntax b s (a (QExpr PgExpressionSyntax s)) Source #
Helps select all rows from a particular table in a database that
satisfy a certain filter condition that is executed at the DB-level.
Note that the table and database declaration is present in
the module generated by genBeamSchema, invoked in the end-user code.
Equivalent to SQL: "SELECT * FROM tbl WHERE ...;" when run using an
appropriate run function from the FramesBeam.Streaming module.
join2 :: (Table a, Table b, GenericVinyl (a Identity) a_names a_rs, GenericVinyl (b Identity) b_names b_rs, RecVec (ZipTypes a_names a_rs), RecVec (ZipTypes b_names b_rs)) => JoinQueryResults a b -> FrameRec (ZipTypes a_names a_rs ++ ZipTypes b_names b_rs) Source #
Function for creating a data frame from the results of executing a join query.