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Search found 8 results on 1 pages for 'dbdatareader'.

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  • SqlDataReader / DbDataReader implementation question

    - by Jose
    Does anyone know how DbDataReaders actually work. We can use SqlDataReader as an example. When you do the following cmd.CommandText = "SELECT * FROM Customers"; var rdr = cmd.ExecuteReader(); while(rdr.Read()) { //Do something } Does the data reader have all of the rows in memory, or does it just grab one, and then when Read is called, does it go to the db and grab the next one? It seems just bringing one into memory would be bad performance, but bringing all of them would make it take a while on the call to ExecuteReader. I know I'm the consumer of the object and it doesn't really matter how they implement it, but I'm just curious, and I think that I would probably spend a couple hours in Reflector to get an idea of what it's doing, so thought I'd ask someone that might know. I'm just curious if anyone has an idea.

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  • DbDataReader with DbTransactions

    - by Gustavo Paulillo
    Its the wrong way or lack of performance, using DbDataReader combinated with DbTransactions? An example of code: public DbDataReader ExecuteReader() { try { if (this._baseConnection.State == ConnectionState.Closed) this._baseConnection.Open(); if (this._baseCommand.Transaction != null) return this._baseCommand.ExecuteReader(); return this._baseCommand.ExecuteReader(CommandBehavior.CloseConnection); } catch (Exception excp) { if (this._baseCommand.Transaction != null) this._baseCommand.Transaction.Rollback(); this._baseCommand.CommandText = string.Empty; this._baseConnection.Close(); throw new Exception(excp.Message); } } Some methods call this operation. Sometimes openning a DbTransaction. Its using DbConnection and DbCommand. The real problem, is in production enviroment (like 5,000 access/day) the ADO operations start throwing exceptions

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  • MemoryStream, XmlTextWriter and Warning 4 CA2202 : Microsoft.Usage

    - by rasx
    The Run Code Analysis command in Visual Studio 2010 Ultimate returns a warning when seeing a certain pattern with MemoryStream and XmlTextWriter. This is the warning: Warning 7 CA2202 : Microsoft.Usage : Object 'ms' can be disposed more than once in method 'KinteWritePages.GetXPathDocument(DbConnection)'. To avoid generating a System.ObjectDisposedException you should not call Dispose more than one time on an object.: Lines: 421 C:\Visual Studio 2010\Projects\Songhay.DataAccess.KinteWritePages\KinteWritePages.cs 421 Songhay.DataAccess.KinteWritePages This is the form: static XPathDocument GetXPathDocument(DbConnection connection) { XPathDocument xpDoc = null; var ms = new MemoryStream(); try { using(XmlTextWriter writer = new XmlTextWriter(ms, Encoding.UTF8)) { using(DbDataReader reader = CommonReader.GetReader(connection, Resources.KinteRssSql)) { writer.WriteStartDocument(); writer.WriteStartElement("data"); do { while(reader.Read()) { writer.WriteStartElement("item"); for(int i = 0; i < reader.FieldCount; i++) { writer.WriteRaw(String.Format("<{0}>{1}</{0}>", reader.GetName(i), reader[i].ToString())); } writer.WriteFullEndElement(); } } while(reader.NextResult()); writer.WriteFullEndElement(); writer.WriteEndDocument(); writer.Flush(); ms.Position = 0; xpDoc = new XPathDocument(ms); } } } finally { ms.Dispose(); } return xpDoc; } The same kind of warning is produced for this form: XPathDocument xpDoc = null; using(var ms = new MemoryStream()) { using(XmlTextWriter writer = new XmlTextWriter(ms, Encoding.UTF8)) { using(DbDataReader reader = CommonReader.GetReader(connection, Resources.KinteRssSql)) { //... } } } return xpDoc; By the way, the following form produces another warning: XPathDocument xpDoc = null; var ms = new MemoryStream(); using(XmlTextWriter writer = new XmlTextWriter(ms, Encoding.UTF8)) { using(DbDataReader reader = CommonReader.GetReader(connection, Resources.KinteRssSql)) { //... } } return xpDoc; The above produces the warning: Warning 7 CA2000 : Microsoft.Reliability : In method 'KinteWritePages.GetXPathDocument(DbConnection)', object 'ms' is not disposed along all exception paths. Call System.IDisposable.Dispose on object 'ms' before all references to it are out of scope. C:\Visual Studio 2010\Projects\Songhay.DataAccess.KinteWritePages\KinteWritePages.cs 383 Songhay.DataAccess.KinteWritePages In addition to the following, what are my options?: Supress warning CA2202. Supress warning CA2000 and hope that Microsoft is disposing of MemoryStream (because Reflector is not showing me the source code). Rewrite my legacy code to recognize the wonderful XDocument and LINQ to XML.

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  • Connection.State Issue

    - by Mostafa
    Hi I've published my new website , In my computer it works fine and no problem , But in the Server I when some user connect at the same time it crash . I found out There is a error at this Method : public static DbDataReader ExecuteReader(DbCommand dbCommand, CommandBehavior commandBehavior) { if (dbConnection.State != ConnectionState.Open) dbConnection.Open(); return dbCommand.ExecuteReader(commandBehavior); } When i trace it , It says ConnectionState is not open , and it's doing opening . Here are my questions : 1- Is it a problem if while ConnectionState is doing opening , we Open the connection again ? 2- What I've missed , that i receive this error ?

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  • SQL SERVER – List of All the Samples Database Available to Download for FREE

    - by Pinal Dave
    It is pretty much very common to have a sample database for any database product. Different companies keep on improving their product and keep on coming up with innovation in their product. To demonstrate the capability of their new enhancements they need the sample database. Microsoft have various sample database available for free download for their SQL Server Product. I have collected them here in a single blog post. Download an AdventureWorks Database The AdventureWorks OLTP database supports standard online transaction processing scenarios for a fictitious bicycle manufacturer (Adventure Works Cycles). Scenarios include Manufacturing, Sales, Purchasing, Product Management, Contact Management, and Human Resources. Coconut Dal Coconut Dal is a lightweight data access layer, for use in projects where the Entity Framework cannot be used or Microsoft’s Enterprise Library Data Block is unsuitable. Anyone who is handwriting ADO.NET should use a library instead and Coconut Dal might be the answer.  DataBooster – Extension to ADO.NET Data Provider The dbParallel DataBooster library is a high-performance extension to ADO.NET Data Provider, includes two aspects: 1) A slimmed down API encapsulation which simplified the most common data access operations (DbConnection -> DbCommand -> DbParameter -> DbDataReader) into a single class DbAccess, to help application with a clean DAL, avoid over-packing and redundant-copy of data transfer. 2) A booster for writing mass data onto database. Base on a rational utilization of database concurrency and a effective utilization of network bandwidth. Tabular AMO 2012 The sample is made of two project parts. The first part is a library of functions to manage tabular models -AMO2Tabular V2-. The second part is a sample to build a tabular model -AdventureWorks Tabular AMO 2012- using the AMO2Tabular library; the created model is similar to the ‘AdventureWorks Tabular Model 2012. SQL Server Analysis Services Product Samples SQL Server Analysis Services provides, a unified and integrated view of all your business data as the foundation for all of your traditional reporting, online analytical processing (OLAP) analysis, Key Performance Indicator (KPI) scorecards, and data mining. Analysis Services Samples for SQL Server 2008 R2 This release is dedicated to the samples that ship for Microsoft SQL Server 2008R2. For many of these samples you will also need to download the AdventureWorks family of databases. SQL Server Reporting Services Product Samples This project contains Reporting Services samples released with Microsoft SQL Server product. These samples are in the following five categories: Application Samples, Extension Samples, Model Samples, Report Samples, and Script Samples. If you are interested in contributing Reporting Services samples, please let us know by posting in the developers’ forum. Reporting Services Samples for SQL Server 2008 R2 This release is dedicated to the samples that ship for Microsoft SQL Server 2008 R2 PCU1. For many of these samples you will also need to download the AdventureWorks family of databases. SQL Server Integration Services Product Samples This project contains Integration Services samples released with Microsoft SQL Server product. These samples are in the following two categories: Package Samples and Programming Samples. If you are interested in contributing Integration Services samples, please let us know by posting in the developers’ forum. Integration Services Samples for SQL Server 2008 R2 This release is dedicated to the samples that ship for Microsoft SQL Server 2008R2. For many of these samples you will also need to download the AdventureWorks family of databases. Windows Azure SQL Reporting Admin Sample The SQLReportingAdmin sample for Windows Azure SQL Reporting demonstrates the usage of SQL Reporting APIs, and manages (add/update/delete) permissions of SQL Reporting users. Windows Azure SQL Reporting ReportViewer-SOAP API usage sample These sample projects demonstrate how to embed a Microsoft ReportViewer control that points to reports hosted on SQL Reporting report servers and how to use SQL Reporting SOAP APIs in your Windows Azure Web application. Enterprise Library 5.0 – Integration Pack for Windows Azure This NuGet package contains a zip file with the source code for the Enterprise Library Integration Pack for Windows Azure.  Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Sample Database

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  • C# Excel file OLEDB read HTML IMPORT

    - by Michel van Engelen
    Hi, I have to automate something for the finance dpt. I've got an Excel file which I want to read using OleDb: string connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=A_File.xls;Extended Properties=""HTML Import;IMEX=1;"""; using (OleDbConnection connection = new OleDbConnection()) { using (DbCommand command = connection.CreateCommand()) { connection.ConnectionString = connectionString; connection.Open(); DataTable dtSchema = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null); if( (null == dtSchema) || ( dtSchema.Rows.Count <= 0 ) ) { //raise exception if needed } command.CommandText = "SELECT * FROM [NameOfTheWorksheet$]"; using (DbDataReader dr = command.ExecuteReader()) { while (dr.Read()) { //do something with the data } } } } Normally the connectionstring would have an extended property "Excel 8.0", but the file can't be read that way because it seems to be an html file renamed to .xls. when I copy the data from the xls to a new xls, I can read the new xls with the E.P. set to "Excel 8.0". Yes, I can read the file by creating an instance of Excel, but I rather not.. Any idea how I can read the xls using OleDb without making manual changes to the xls or by playing with ranges in a instanciated Excel? Regards, Michel

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