Orville.PostgreSQL.Expr

This module provides access to functions and types intended to help build SQL statements directly in a relatively safe manner while also always providing a way to write exactly the SQL you need. The SQL construction functions all require specific types as their arguments to communicate what particular fragment of SQL they expect to take as an argument. These types generally provide a SqlExpression instance, however, meaning that if Orville does not support constructing the exact SQL fragment you want to pass for that argument directly you can always use unsafeSqlExpression to construct a value of the required type. This means you can use as many of the "safe" construction functions provided here as possible while substituting in hand-written SQL at only the exact points you need.

For instance, the following code snippet shows how you could construct a BEGIN TRANSACTION ISOLATION LEVEL SOME NEW ISOLATION LEVEL statement if PostgreSQL added SOME NEW ISOLATION LEVEL and Orville did not yet support it.

  import qualified Orville.PostgreSQL.Expr as Expr
  import qualified Orville.PostgreSQL.Raw.RawSql as RawSql

  customerBeginTransaction :: Expr.BeginTransactionExpr
  customerBeginTransaction =
    Expr.beginTransaction
      (Just (Expr.isolationLevel (RawSql.unsafeSqlExpression "SOME NEW ISOLATION LEVEL")))

Since: 1.0.0.0

Documentation

module Orville.PostgreSQL.Expr.BinaryOperator

module Orville.PostgreSQL.Expr.ColumnDefinition

module Orville.PostgreSQL.Expr.Count

module Orville.PostgreSQL.Expr.Cursor

module Orville.PostgreSQL.Expr.DataType

module Orville.PostgreSQL.Expr.Delete

module Orville.PostgreSQL.Expr.GroupBy

module Orville.PostgreSQL.Expr.IfExists

module Orville.PostgreSQL.Expr.Index

module Orville.PostgreSQL.Expr.Insert

module Orville.PostgreSQL.Expr.LimitExpr

module Orville.PostgreSQL.Expr.Math

module Orville.PostgreSQL.Expr.Name

module Orville.PostgreSQL.Expr.OffsetExpr

module Orville.PostgreSQL.Expr.OrderBy

module Orville.PostgreSQL.Expr.Query

module Orville.PostgreSQL.Expr.ReturningExpr

module Orville.PostgreSQL.Expr.Select

module Orville.PostgreSQL.Expr.SequenceDefinition

module Orville.PostgreSQL.Expr.TableConstraint

module Orville.PostgreSQL.Expr.TableDefinition

module Orville.PostgreSQL.Expr.TableReferenceList

module Orville.PostgreSQL.Expr.Time

module Orville.PostgreSQL.Expr.Transaction

module Orville.PostgreSQL.Expr.Update

module Orville.PostgreSQL.Expr.ValueExpression

module Orville.PostgreSQL.Expr.WhereClause