Chez-odbc

this is library for chez-scheme connecting to ODBC datasources.

License

LGPLv3+

Usage

Procedures

Procedure: connect

• Usage:
  • (connect Datasource UID [PWD])
  • (connect DSN)

Create an odbc connect to datasource.

Example:

(import (prefix (odbc dbi) dbi:))
;;Procedure connect
(define c (dbi:connect (getenv "DSN")))

Procedure: cursor

• Usage:
  • (cursor connect)

Alloc a cursor object, all queries go through cursor.

Example:

(define cs (dbi:cursor c))

Procedure: query

• Usage:
  • (query cursor sql)

Execute query.

Example:

(dbi:query cc "select now()")

Procedure: commit, rollback

• Usage:
  • (commit connect)
  • (rollback connect)

Commit/Rollback transactions on connection: connect

Procedure: row-count, number-of-columns, col-defs

• Usage:
  • (row-count cursor)
  • (number-of-columns cursor)
  • (col-defs cursor)

col-defs returns: vector of (column-name column-type column-size)

Procedure: fetch-one

• Usage:
  • (fetch-one cursor)

Fetches one row from result. Returns a vector of values. Example:

 (let lp ((d (dbi:fetch-one cc)))
   (if d
	 (begin
	   (format (current-output-port)
		   "~a\n" ;;(pretty-print)
		   d)
	   (lp (dbi:fetch-one cc))
	   )))

Procedure: cursor-type-map-proc-set!

• Usage:
  • (cursor-type-map-proc-set! cursor type-map-proc)

• type-map-proc is a proc takes an integer(sql-type) and returns a list: (convert-code length convert-proc) convert-code sql-type code is defined in (odbc types) as in sqlext.h and sql.h length could be #f which means use column-definition’s length convert-proc takes a bytevector and a length and returns data in desired type

  Example:

     (import (prefix (odbc dbi) dbi:)
  	(odbc types))
  
     (define DSN (getenv "DSN"))
  
     (define c (dbi:connect DSN))
     (define cc (dbi:cursor c))
  
     (define (timemap x)
  	(if (pair? (memq x (list SQL_TYPE_TIME
  	                         SQL_TYPE_DATE
  				 SQL_DATE
  				 SQL_TIME
  				 SQL_TIMESTAMP)))
             (list SQL_C_TIMESTAMP 200
                   bytevector-truncate!)
  	    (dbi:default-map-sql-type x)))
  
     (dbi:cursor-type-map-proc-set! cc timemap)
      

Copyright

Chaos Eternal (c) 2016