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POParameter naming using System.Data.Common
 

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    <p>This is probably an oldie-but-goodie. I am using System.Data.Common for an interchangeable Oracle/SQL Server/SQLite data access library. During the constructor I take the connection string name and use that to determine the underlying provider type. The reason I do this is to handle the different IDbParameter naming conventions for each provider. For example, Oracle likes :parameter whereas SQL Server and SQLite like @parameter. The default is ? to cover Oledb.</p> <p>Question: Is this all unnecessary and is there some simple thing I'm missing that should simply take care of this? If my IDbCommand.CommandText = "select id, name from my.table where id = :id" am I covered? For now I'm just adopting ? as the default and then RegEx'ing my way to the right parameter identifier before executing the command.</p> <p>Thanks.</p> <pre><code> /// &lt;summary&gt; /// Initializes a new instance of the &lt;see cref="RelationalGateway"/&gt; class. /// &lt;/summary&gt; /// &lt;remarks&gt;You must pass in the name of the connection string from the application configuration /// file rather than the connection string itself so that the class can determine /// which data provider to use, e.g., SqlClient vs. OracleClient.&lt;/remarks&gt; public RelationalGateway(string connectionStringName) { if (string.IsNullOrEmpty(connectionStringName)) throw new ArgumentNullException("connectionStringName"); if (ConfigurationManager.ConnectionStrings[connectionStringName] == null || ConfigurationManager.ConnectionStrings[connectionStringName].ConnectionString.Length == 0 || ConfigurationManager.ConnectionStrings[connectionStringName].ProviderName.Length == 0) { throw new InvalidOperationException(string.Format( "The configuration file does not contain the {0} connection ", connectionStringName) + "string configuration section or the section contains empty values. Please ensure the " + "configuration file has the appropriate values and try again."); } _connectionString = ConfigurationManager.ConnectionStrings[connectionStringName].ConnectionString; _providerName = ConfigurationManager.ConnectionStrings[connectionStringName].ProviderName; _theProvider = DbProviderFactories.GetFactory(_providerName); _adapter = _theProvider.CreateDataAdapter(); //GetConnection(); DetermineProviderSpecificParameters(); } </code></pre> <p>The DetermineProviderSpecificParameters bit basically figures out "?" or ":" or "@" or something else.</p> <p>UPDATE Here's how I'm handling the details thus far:</p> <ol> <li><p>Get the right parameter string:</p> <p>private void DetermineProviderSpecificParameters() { // Check for supported providers. This is so that parametized queries to limit // by spatial extent are correctly created. string shortName = _providerName.Substring(_providerName.LastIndexOf(".") + 1);</p> <pre><code> switch (shortName) { case "SqlClient": _param = "@"; _ql = "["; _qr = "]"; break; case "SQLite": _param = "@"; _ql = string.Empty; _qr = string.Empty; break; case "OracleClient": _param = ":"; _ql = string.Empty; _qr = string.Empty; break; default: _param = "?"; _ql = string.Empty; _qr = string.Empty; break; } } </code></pre></li> <li><p>call a little helper before I execute each command to "cleanify" or "parameterific" it or however we call this half-assed hack:</p> <pre><code>private void MakeProviderSpecific(IDbCommand command) { foreach (IDataParameter param in command.Parameters) { param.ParameterName = GetProviderSpecificCommandText(param.ParameterName); } command.CommandText = GetProviderSpecificCommandText(command.CommandText); } </code></pre></li> <li><p>And this calls a little regex to do to do:</p> <pre><code>public string GetProviderSpecificCommandText(string rawCommandText) { return Regex.Replace(rawCommandText, @"\B\?\w+", new MatchEvaluator(SpecificParam)); } </code></pre></li> </ol> <p>Yuck. Still searching for a relatively simple solution but the advice thus far is certainly appreciated.</p>
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    1. CONot sure, but one option to do what you're looking at doing is NHibernate.
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    2. COI'm using NHibernate for other projects but this is a utility library for my other devs to use that gives them a quick-but-not-too-dirty Db access approach. Plus I use this as the core of my code for clients who are anti-open source. Yep, I hand roll data access code more times than I can to think about! :-(
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