StephenLeafWW / adodb

Nim access to ADO compatible database

Module adodb

adodb enables simple access to Microsoft ADO compatible databases. It is inspired from node-adodb. adodb provides "out-of-the-box" SQL literal interpolation ({} fields, similar to strformat module) and timestamp literal processing. Some well known aggregation functions like DSum, DMin, DMax, etc. are also provided

adodb internally uses awesome winim for low-level access to Microsoft ADO and COM processing.

Code Example

import adodb

# Connect to Microsoft Access 2003 DB
let connect = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\data\test.mdb"
let ado = newADODB(connect)

# Execute SQL statement in db
let id = 100
ado.exec(sql"DELETE * FROM Users WHERE ((UserID)>{id})")

# Retrieve data from db
let rst = ado.query("SELECT * FROM Users")

# Access data
for rowIdx, row in rst:
   for idx, name, value in row.fields:
      echo "Row ", rowIdx, ", Fld[", idx," | ", name, "] = ", value

If the code above is saved to sample.nim you can compile it, as follows:

nim c sample.nim

Construction, destruction, properties and methods of adodb

Constructor:

let ado = newADODB(connection)

Database connection strings:

• For Access 2000-2003 (*.mdb):

connection = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=<path-to-mdb-file>;"

• For Access > 2007 (*.accdb):

connection = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=<path-to-accdb-file>;Persist Security Info=False;"

Methods:

exec - execute SQL statement, no data is returned
query - execute SQL statement and returns ADORecordset object

Methods of ADORecordset

Methods:

len/rowCount - return recordset's row count
[index] - return row by index (from 0 to len - 1)

Iterators:

items - iterates through recordset rows (return ADORow)
pairs - iterates through recordset rows, return (index, ADORow)

Methods of ADORow

Methods:

len/fieldsCount - return row's field count
[index] - return value of field by index
[name] - return value of field by name

Iterators:

items - iterate through fields, return values
pairs - iterate through fields, return (index, value)
fields - iterate through fields, return (index, name, value)

Deal with NULL variants

Two useful templates are added to manage fields with no value (variant.VT_NULL)

isnull - check if variant is NULL
nz - replaces value NULL with appropriate value

Data aggregation functions

AdoDB provides several useful data aggregation methods:

	dMin (field, domain [, criteria]) is equal to SELECT Min(field) FROM domain [WHERE criteria])
	dMax (field, domain [, criteria])     ...     SELECT Max(field) FROM domain [WHERE criteria]
	dSum (field, domain [, criteria])     ...     SELECT Sum(field) FROM domain [WHERE criteria]
	dCount (field, domain [, criteria])   ...     SELECT Count(field) FROM domain [WHERE criteria]
	dFirst (field, domain [, criteria])   ...     SELECT First(field) FROM domain [WHERE criteria]
	dLast (field, domain [, criteria])    ...     SELECT Last(field) FROM domain [WHERE criteria]
	dLookup (field, domain [, criteria])  ...     SELECT field FROM domain [WHERE criteria]

Install

With git on windows:

nimble install https://github.com/zolern/adodb

Without git:

1. Download and unzip this module (by click "Clone or download" button).
2. Start a console, change current dir to the folder which include "adodb.nimble" file.
   (for example: C:\nim\adodb>)
3. Run "nimble install"

For Windows XP compatibility, add:

-d:useWinXP

Documents

• adodb
• sqlformat

License

Read license.txt for more details.

Copyright (c) 2019 Encho Topalov, Zolern. All rights reserved.