diff options
| author |  Adam Chlipala <adamc@hcoop.net> | 2008-10-21 18:44:52 -0400 |
|---|---|---|
| committer | Adam Chlipala <adamc@hcoop.net> | 2008-10-21 18:44:52 -0400 |
| commit | d66bb9f256db65e3487dec361a4a5a9d7ee238b0 (patch) | |
| tree | 02a7bb0fa4faec1697c91fbc22c46014b3ff49c5 /demo | |
| parent | d249f18f65213b5a198f39e254982293ecaa0e10 (diff) | |
Sql demo
Diffstat (limited to 'demo')
| -rw-r--r-- | demo/prose | 12 | ||||
| -rw-r--r-- | demo/sql.ur | 52 | ||||
| -rw-r--r-- | demo/sql.urp | 3 | ||||
| -rw-r--r-- | demo/sql.urs | 1 |
4 files changed, 68 insertions, 0 deletions
@@ -59,3 +59,15 @@ listShop.urp <p>The <tt>ListFun</tt> module defines a functor for building list editing sub-applications. An argument to the functor <tt>Make</tt> must give the type to be stored in the lists, along with marshaling and unmarshaling functions. In return, the functor returns an entry point function.</p> <p>The <tt>ListShop</tt> modules ties everything together by instantiating <tt>ListFun.Make</tt> with structures for integers and strings. <tt>show</tt> and <tt>read</tt> can be used for marshaling and unmarshaling in both cases because they are type-class-generic.</p> + +sql.urp + +<p>We see a simple example of accessing a SQL database. The project file specifies the database to connect to.</p> + +<p>A <tt>table</tt> declaration declares a SQL table with rows of a particular record type. We can use embedded SQL syntax in a way that leads to all of our queries and updates being type-checked. Indeed, Ur/Web makes strong guarantees that it is impossible to execute invalid SQL queries or make bad assumptions about the types of tables for marshaling and unmarshaling (which happen implicitly).</p> + +<p>The <tt>list</tt> function implements an HTML table view of all rows in the SQL table. The <tt>queryX</tt> function takes two arguments: a SQL query and a function for generating XML fragments from query result rows. The query is run, and the fragments for the rows are concatenated together.</p> + +<p>Other functions demonstrate use of the <tt>dml</tt> function, for building a transaction from a SQL DML command. It is easy to insert antiquoted Ur code into queries and DML commands, and the type-checker catches mistakes in the types of the expressions that we insert.</p> + +<p> diff --git a/demo/sql.ur b/demo/sql.ur new file mode 100644 index 00000000..9e9effff --- /dev/null +++ b/demo/sql.ur @@ -0,0 +1,52 @@ +table t : { A : int, B : float, C : string, D : bool } + +fun list () = + rows <- queryX (SELECT * FROM t) + (fn row => <xml><tr> + <td>{[row.T.A]}</td> <td>{[row.T.B]}</td> <td>{[row.T.C]}</td> <td>{[row.T.D]}</td> + <td><a link={delete row.T.A}>[delete]</a></td> + </tr></xml>); + return <xml> + <table border=1> + <tr> <th>A</th> <th>B</th> <th>C</th> <th>D</th> </tr> + {rows} + </table> + + <br/><hr/><br/> + + <form> + <table> + <tr> <th>A:</th> <td><textbox{#A}/></td> </tr> + <tr> <th>B:</th> <td><textbox{#B}/></td> </tr> + <tr> <th>C:</th> <td><textbox{#C}/></td> </tr> + <tr> <th>D:</th> <td><checkbox{#D}/></td> </tr> + <tr> <th/> <td><submit action={add} value="Add Row"/></td> </tr> + </table> + </form> + </xml> + +and add r = + () <- dml (INSERT INTO t (A, B, C, D) + VALUES ({readError r.A}, {readError r.B}, {r.C}, {r.D})); + xml <- list (); + return <xml><body> + <p>Row added.</p> + + {xml} + </body></xml> + +and delete a = + () <- dml (DELETE FROM t + WHERE t.A = {a}); + xml <- list (); + return <xml><body> + <p>Row deleted.</p> + + {xml} + </body></xml> + +fun main () = + xml <- list (); + return <xml><body> + {xml} + </body></xml> diff --git a/demo/sql.urp b/demo/sql.urp new file mode 100644 index 00000000..1b8bb5a4 --- /dev/null +++ b/demo/sql.urp @@ -0,0 +1,3 @@ +database dbname=test + +sql diff --git a/demo/sql.urs b/demo/sql.urs new file mode 100644 index 00000000..6ac44e0b --- /dev/null +++ b/demo/sql.urs @@ -0,0 +1 @@ +val main : unit -> transaction page |