Sqldatareader get column names execute(query, { 'status': 1 }) # SqlDataReader objects allow you to read data in a fast forward-only manner. Try it. Without this attribute the property name is assumed to be the column name. RecordsAffected Gets the number of rows changed, inserted, or deleted by execution of the When you execute a SQL query and read the results with SqlDataReader, you have two options for getting column values by name (instead of by ordinal number): Use the indexer How to get the column names from a SqlDataReader in C#? Here’s a code snippet demonstrating how to do it. I have used this method during the login section and it works perfectly there (code below). GetName(i); } Also you can create an extension method like below: Do you want to check if a column exists in a SqlDataReader instance in C# ?. IsDBNull() and uses the generic SqlDataReader. ColumnName To get the name of all DataColumns within your DataTable: Dim name(DT. More worrying is that you're converting from a double to string and then back to double. If the column name cannot be determined, a null value is returned. GetValue方法按列名获取数据。SqlDataReader是. GetString() method accepts only parameter with int type. select * will return all the columns from a table. What is the best way of handling trying to get data from a DataReader that has more than one column with the same name? Because of the amount of work involved and because we don't want to lose support from a vendor by changing the stored procedures we are using to retrieve the data, I am trying to find another way to get access to a column that shows up more than once The @TableName parameter contains the name of the table that I want to retrieve column names from. These are the top rated real world C# (CSharp) examples of System. Invalid cast from 'System. C# SQLDataReader accessing by column name. If I load the data via an adaptor class into a datatable, I can access the field names by something like DataTab. SqlDataReader reader = cmd. One of the simplest solution is to navigate to all the fields within the data reader and check the name of the field using the GetName method as shown below. Home; C# / CSharp Tutorial; Language Basics; Data Type; Operator; Statement; String; struct; Get table schema from SqlDataReader : Column Type Name « ADO. Employee Table Metadata I'm not worried about data types, just column names. Data. notsupported. But I'm confused why datareader doesn't add table name before columns. public static void Main() { string sql = "SELECT 1 AS IntColumn, 'FizzBuzz' AS The provided answer demonstrates a good understanding of the original user's question and offers a complete solution using SqlDataReader. Columns(1). GetColumnSchema() method, which enables the use of the IDbColumnSchemaGenerator interface to populate the DbColumn schema metadata without using a DataTable. ToString()) == 1; I then get an FormatException error, stating that "Input string was not in a correct format. ". GetString(0) will it use the first column you selected in your query or the firstt column on the table. Here is The code : You can use SqlDataReader. Can you get the column names from a SqlDataReader? Related. Use A Data Reader: 8. System. GetSchemaTable(). I want to retrieve the datatype and Size of a value from id_declarant. GetName to get the column name. If the database changes (which is actually extremely unlikely in this case) the code breaks. Using DataTable in . DataTable that describes the column metadata of the The example above uses a string indexer, where the string is the column name from the SQL query (the table column name if you used an asterisk, *. . Columns name(i) = column. Example while (dataReader. The way I am doing it right now is by using a while loop and reading values from the item property like so : Recently i add DateofBirth to a table . Examples. So you have to pass column number instead of column name to get the value. (I'd strongly advise against it I can enumerate the results and list the values. Data; using System. I have created 2 sample methods: Try the query below. Get info about each column: Name, Ordinal and FieldType: 5. What I'd like to do is look up a column from a DataTable schema using the column name and then get the datatype of that column. SqlDataReader reader = command. bool isConfirmed = int. I'm looping through a DataTable like this. NET for data access , there are times when you want to check to see if a column exists in a SqlDataReader object. ToString(); it will always give you a value that can be a empty string (String. Remember that a returned column might be String[] columnRestrictions = new String[4]; // For the array, 0-member represents Catalog; 1-member represents Schema; // 2-member represents Table Name; 3-member represents Column Name. columns where table_name = 'shop' -- enter table name only, do But it feels very unstable. ExecuteReader()) { // This will return false - we don't care, we just want to make sure the schema table is there. var dateString = MyReader. ExecuteReader(); // Call GetOrdinal and assign value to variable. This reference helped clear things up a bit, but I'm still not sure if there's an elegant way of doing it. But yes, a do {} while() is a far better (and cleaner) approach than the convoluted, and less flexible, approach shown in the accepted answer. CreateCommand(); cmd. dotConnect for SQL Server Documentation. At least fix your code to: using System; using System. I want to know if there's a way I need to read each column value and concatenate with the resultVal. Read()) { yield return reader; } } And the caller can get strongly-typed objects using: Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog I implemented support for the attributes NotMapped and Column used also by the entity framework. Name, the runtime is saying that "r. Use column name to index data: 7. the table you are using is a permanent table or temp table? – Kashif Qureshi. IsDBNull the best/most efficient way to check for nulls?. ExecuteReader() reader. Appears I stand corrected. GetSchemaTable(); DataTable dt = new DataTable(); List It's generally a good practice to have your model properties match your column names. However, for best performance, the DataReader provides a series of methods that allow you to access column values in their native data types (GetDateTime, GetDouble, GetGuid, GetInt32, and so on). Empty if you need to compare). 10. GetFieldValue method uses generics to return the value of a column as the requested data type, which is nice, but it also requires us to know and pass the column index instead of just using its name, which is less nice. Columns(i). I'm using the following code to output query result from it: command. ToString() = "x" Then Dim columnName As String = [THIS IS WHAT I WANT] End If Next The fact you're getting an exception would be easier to solve if you told us what kind of exception you get. Item[String] Source: System. Name is not in the list of IDataReader - GetColumnNames. ItemArray columnCount = columnCount + 1 If cell. GetOrdinal performs a case-sensitive lookup first. GetSchemaTable(); // Find all Execute multiple SELECT statements using a SqlCommand object and read the results using a SqlDataReader object: 2. I just one way to change the column name of the data reader. GetColumnSchema() Remarks. SqlDataReader. Here, parameter i is the zero-based column ordinal. This column cannot contain a null There is nothing in the call to GetSchemaTable on SqlConnection which will allow you to figure this out. // If you simply assign reader object itself as the data you wont be // able to get data once the reader or connection is closed. Strange Behavior with SqlDataReader and long columns. I do not want to alter the query itself (changing the names to have spaces) because this query is called in another My question is how to get the number of rows returned by a query using SqlDataReader in C#. OLEDB. I dont think there is a performance gain when using ordinal or column names, it is more on best practice and coding standards and code maintainability really. With this solution I am able to get only base table names and columns but not the view names. public override string GetName(int ordinal) Parameters ordinal int. NET Core. Andrey Gordeev Andrey Gordeev. Commented Apr 8, 2012 at 18:51. As an example, if you wanted to get the type of the first column you could do var firstColType = reader. IsDBNull() C# (CSharp) System. These custom attributes are basically present to allow us to have different property names and column names (EmployeeID property populated from Employee_ID Imports System Imports System. net like MS Access? 1. SqlClient or should I do the mapping myself? I can get a string representation back from . But errors appears. Share. I'm working in Visual Basic 2008 Express and have created a SQL database, "MyDatabase" with 1 table called "MyTable". The only robust way is to use AS in the SQL-query to make sure your column names/aliases are unique otherwise you would to access the fields by index (0 / 1 / 2 etc. Adapted from the above link, you could get a list of all of your columns with the following: List<string> myCols = new List<string>(); DataTable schema = is there a class that can do that in System. Invalid column name 'DateofBirth'. ID), but the source table/subquery aliases are lost. the number of columns is unkown. NotMapped Attribute. 26. Get table schema from SqlDataReader : Column Type Name « ADO. If selecting from more than one table or subquery with aliases a and b like select a. In the code below, reader is a SqlDataReader and command is a SqlCommand object. CSV file the way that they appear in the database which is not ideal. Since I don't know the datatype, I can't do datareader. I'd be gathering the actual data type from the main table rather than the view in this case. SqlDataReader. Nullable`1[[System. 0. Name" or "s. You only have to open the connection once. for (int i = 0; i < reader. Then you can just return the value from inside the if statement, and doesn't have to store it in a variable until you have closed the objects. I am unable to take the 'Name' data from the Product table. COLUMNS WHERE TABLE_NAME = 'vwGetData' ORDER BY Gets the value of the specified column in its native format given the column name. However, I have no idea, how to loop through columns in datareader. Follow I have a DataTable that I'm parsing through and I'm trying to find the column name of a given column when its value = "x". CSV file; however, the column names are showing up in the . You should use parameterised queries, instead of concatenating values There is a GetName function on the SqlDataReader which accepts the column index and returns the name of the column. HasRows instead of FieldCount (I probably use HasRows more often than FieldCount). GetSchemaTable returns a data table with column information - but all the SqlDataReader. Hot Network Questions What's wrong with my formal translation of "every positive number has exactly two square roots"? Would it be possible to use a Cygnus resupply i am trying to get the data type of each column given to do some verification i already tried the getSchemaTable but it only gives me the schema of a table without values. GetOrdinal("CustomerID"); // Use variable with GetString inside of loop. Hot Network Questions Question on the concept of the Big Bang Theory Nonograms You can use the GetFieldType method, passing in the ordinal of the column whose type you wish to retrieve. Try Dim reader As SqlDataReader = cmd. e. namespace adonet. You obtain data by reading each row from the data stream. How to check for the column name in an SqlDataReader Object in C# ? public static bool IsColumnExists Suppose I have POCO entities being read from a database and they each have "ID" as their primary key column name. ColumnName. I am pulling in a Dapper FastExpando object and want to be able to reference the column names dynamically at run time rather than at design/compile time. This line is asking for an Sql Injection: SqlStr = "Select * from TB_User where UserID=" + Label1. Then you're focusing on entirely the wrong problem. For me reader. the least-janky solution is to use SQL CLR. * from a, b, then the selected columns will include two ID columns (a. GetSchemaTable to get information about the columns for the current result set (I think - the documentation isn't clear about whether or not it supports multiple result sets). Gets the value of the specified column in its native format given the column name. NET Framework中用于读取数据的一个重要类，它提供了一种简单、有效的方式来从数据库中检索数据。 阅读更多：SQL 教程 SqlDataReader简介 SqlDataReader是ADO. SqlDataReader displaying like fields. GetName returns the column name but not the table name. I've seen some answers about this but none were clearly defined except for one that states to do a while loop with Read() method and increment a counter. If it fails, a second case-insensitive search is made. Get<Datatype> functions used to retrieve specific DataType values from DataReader. Select(reader. GetSchemaTable will return a lot of information about the columns, including their name but also size, type, etc. 32. – CuriousOne. CommandText = "SELECT * FROM devices WHERE device_level='" + ACCESS_LVL + "'" + "ORDER BY device_name"; reader = The read-only column schema collection). ASH ASH. Name" because when evaluating, the reader is simply returning two columns, both just named "Name" So when searching for r. Asynchronously returns a System. Value Field that this check is rarely used. It's generally a good practice to have your model properties match your column names. I have sql query in my asp. Get data from SqlDataReader by Data type: 6. connect(user=DB_USER, password=DB_USER_PASSWORD, host=DB_HOST, database=DB_NAME) cursor = cnx. GetName). NET Framework Data Provider for ODBC Your code is bad from a security perspective. Get column name from SQL Server. GetSchemaTable in this case. Name as ProductName," + " StockRequest. But GetValue() can be used to retrieve any data type value. Implements. Reference data in SqlDataReader by column name: 7. What 'length' parameter should I pass to SqlDataReader. This method is an implementation of IDbColumnSchemaGenerator. I have a table with 3 columns in order: ID, Dir, Email. And Locally it's work fine. TechTarget and Informa Tech’s @nawfal This approach handles the DBNull issue the OP posted about and when defined as extension methods they read better (IMHO). Commented Nov 8, 2013 at 6:26. String indexers are much more readable . GetOrdinal is kana-width insensitive. GetString but only reader. The details of the table are provider dependent, for SQL Server it is documented in SqlDataReader. Home; Tutorial. NET will throw an IndexOutOfRange exception. NET Connector for SQL Server, MySQL, Access, PostgreSQL or anything else, the DataTable and DataColumn This kind of information is available through the call GetSchemaTable. This name always reflects the most recent naming of the column in the current view or command text. How exactly did you verify that there were 6 columns? This class of issue is almost always caused by the big three - So it is connected to the wrong database. All I want is: change some column name in the data reader, just before binding to grid. We can see GetOrdinal sourcecode from SqlDataReader it will return a index from _fieldNameLookup. reader. Format data when reading the data from SqlDataReader: 4. DataTable (or DataColumn, or DataSet, or DataRow) is a generic . SqlClient; class Program { static void Main() { string str = "Data Source=(local);Initial Catalog=Northwind;" + "Integrated Security=SSPI"; ReadGetOrdinal(str); } private static void ReadGetOrdinal(string connectionString) { string queryString = "SELECT reader. I can't figure out why it doesnt work here (code above) aswell. ExecuteReader(); SqlDbType type = (SqlDbType)(int)reader. Read()) { var value = dataReader. StoreID = Store. GetSqlString(column), and since I don't know the name of the column the user may have selected, I can't do datareader. GetFieldValue() to read the value. You can easily find out if the column exists in the SqlDataReader object as shown in the code snippet. Using SqlDataReader. 1. So I am trying to get the column values from the @TableName table. Parse(sqlDataReader["IsConfirmed"]. SQL Server and SqlDataReader. Read to read result set: 2. *, b. However, from the documentation for the IsKey column (emphasis mine):. You can use methods such as GetString() to get a column value converted to its primitive type. SqlClient SqlDataReader. Count) As String Dim i As Integer = 0 For Each column As DataColumn In DT. What I need to be able to do though is also enumerate the field names that come back from the sproc. I retrieve the columns from. GetOrdinal("column")). Thus, is the reader. My question is how to get the number of rows returned by a query using SqlDataReader in C#. GetSchemaTable(): It returns a System. Net « C# / CSharp Tutorial. Let's see if we can do better with a simple extension method. ExecuteReader(); Now I want to convert the result for each row into byte[]. You have to access the individual table that is within the DataSet to retrieve the values. You have to loop the reader to get the values from it. GetInt32(reader. Or it is connected to the right database but the database has two tables with the same name. 109. In CLR you get a SqlDataReader that you can use to examine the resultset shape. 0; Gets the name of the column, given the zero-based column ordinal. GetValue by column name. Is datareader quicker than dataset when populating a datatable? 17. It might seem that you can, using the IsKey column value, which should return true for anything that contributes to uniquely identifying the record in the table. Text; I then try to get the value of a column, called IsConfirmed (which is represented as a bit type column in the database) and convert it to bool. In particular, note the following: The . The issue with caching the result of GetOrdinal applies to using reader["field_a"] as well, but this is often a micro-optimisation when reading through large datasets, and for me the improved readability trumps using a cast and The first step in our function is to get the list of columns that are in our SqlDataReader input parameter. GetBytes() 0. Text; This is how to retrieve a Column Name from a DataColumn: MyDataTable. SqlCommand cmd = new SqlCommand("select leave_details from LeaveTable"); SqlDataReader obj; con. Every row in datareader contains 10 columns. this means that provided you used a . This one is not working: Get the FieldCount (number of columns in the result set) and then loop through the fields (columns) in each row of the DataReader retrieving the data. I need something like this: DataReader Column Description; ColumnName: The name of the column; this might not be unique. After connecting to the database, can I get the name of all the columns that were returned in my SqlDataReader? I want to write a routine that loads a table (or query) and outputs it to a text file, with the field names in the first row. GetOrdinal(columnName)); } } } This article shows three ways to retrieve database column names from DataSet and DataReader in ADO. (+1). You will need one or more of the following medthods: GetFieldType(int) - returns the Type of the column. SqlClient. Improve this answer. Name is selected into the DataReader, it reads only the field name - Name. Linq; public static class SqlDataReaderExtensions { public static int GetNthOrdinal(this SqlDataReader reader, string columnName, int nthOccurrence = 1) { // Get the schema which represents the columns in the reader DataTable schema = reader. so you still know what columns you are returning. I have seen on MSDN - DBNull. Here are some thing that don't work: SqlDataReader. GetDataTypeName(int) - returns the Name of the back-end database column type. Column Attribute. After executing the query, I will store the result in SqlDataReader as it has multiple columns as output. I then try to get the value of a column, called IsConfirmed (which is represented as a bit type column in the database) and convert it to bool. (Here the 0 is "the ordinal of the EmployeeId column; you can use GetOrdinal to get the ordinal for a named column. Items The problem with ordinal is if the order of the columns change and you are forced to modify the consumer code for the DataReader, unlike using column names. Here's the situation: First I build the structure Of grid (structure is in the table in database that was filled based on the output of a stored procedure in the system in the past) Note: Not related to my question but, the real reason i want to know if a column exists is because i want to get the ordinal position of a column, without throwing an exception if the column doesn't exist: int columnOrdinal = reader. The zero-based column ordinal. The table names are Store, Product, StockRequest, StoreInventory. Must have read your mind ;-) Enumerate SqlDataReader Columns. ) You'll need to change your method's return type to int as well, of course - or call ToString if you really want the value as a string. SqlClient; using System. Depending on the scenario, I have also used SqlDataReader. Enumerate SqlDataReader Columns. ) instead of by name. Format("{0}. ColumnOrdinal: The zero-based ordinal of the column. FieldCount I'm trying to write some generic code in VB. is There a Column Count Property in VB. GetOrdinal (_fieldNameLookup field is a FieldNameLookup class) _fieldNames is a hashtable stores the index, match via case-sensitive You could use alias to give a different name to the duplicate column. 4k 15 15 This article shows three ways to retrieve database column names from DataSet and DataReader in ADO. Int32, mscorlib]] 11. How to read the column SqlDataReader. // Now we specify the Table_Name and Column_Name of the columns what we want to get schema information. connector. DataTable dt = reader. read column values as Sql* types using the SqlDataReader Get Value By Column Name (Not Ordinal Number) 0. DECLARE @maxRowSize int SET @maxRowSize = ( SELECT SUM(DataSize) AS MaxRowSize FROM ( SELECT COLUMN_NAME, DATALENGTH(COLUMN_NAME) as DataSize from information_schema. GetString(0); //The 0 stands for "the 0'th column", so the first column of the result. cnx = mysql. You can read the columns by ordinal number (0-based index) or by name. Any ideas on how to retrieve the values from the database without knowing either the datatype or the column name? Thanks in You can use the query below to get the column names for your table. e. And correct, a result set must have at least one column. SqlDataReader only implements these Get methods that read columns by ordinal number – such as GetString(int i). I would use the following and wouldn't worry too much: Use SqlDataReader. Possible errors are: Column is not DateTime, thus GetDateTime doesn't work at all; firstMove is not a valid column name at all, so you can not access that column; Assuming the column really exists and is of type DateTime I tend to use the following: You can get the Schema Table from your SqlDataReader dr to get the column names, save the names to a List<string> and add them as columns on a new DataTable, then fill that DataTable using indexing on dr with the names from the list: DataSet ds = new DataSet(); DataTable dtSchema = dr. See MSDN for more info. SqlServer Namespace / SqlDataReader Class / GetName Method. How do I reach a specific column of sqldatareader in C#. Thanks! sql-server; sql-server-2008-r2; sql-server-2016; Share. FieldCount; i++) { string columnName = reader. How to get table name of a column from SqlDataReader. How to get number of rows using SqlDataReader in C#. Fastest method for SQL Server inserts, updates, selects. How to Check for Column Name in SqlDataReader object in C# ? Examples. You need to provide also the database-name + schema-name + table-name: string table = string. The same syntactical from pandas import DataFrame import pyodbc cnxn = pyodbc. GetOrdinal() accepts index no of the column as well as Column Name as column reference which is a advantage of using this method from my point of view. Dim _ExecutionResultsReader As SqlDataReader _ExecutionResultsReader = _DMTSQLCommand. To add some value to the answers, I included a possible extension method to return the column names for a given DataReader. Count of number of columns using SQL 使用SqlDataReader. Save time by calling GetOrdinal once and assigning the results to an integer variable for use within the loop. StockLevel from Store" + " LEFT JOIN StoreInventory ON StoreInventory. catch approach as shown below which is not efficient. Item[Int32] Gets the value of the specified column in its native format given the column ordinal. I'd like to put the table in csv file. COLUMNS WHERE TABLE_CATALOG = '{0}' AND TABLE_SCHEMA = '{1}' AND TABLE_NAME = '{2}' AND You're missing basic C# syntax. public override Task<DataTable?> GetSchemaTableAsync(CancellationToken Most of the metadata for a query results is available in the DataTable returned by DataReader. My problem is that I am trying to fill a multi-dimensional array with the first row being the column header Your code is bad from a security perspective. Make sense? How to get data by SqlDataReader. execute("""SELECT ID, NAME AS Nickname, ADDRESS AS Residence FROM tablez""") DF = DataFrame(cursor. There is a GetName function on the SqlDataReader which accepts the column index and returns the name of the column. Open(); obj = cmd. I have to read the data from a SQL Server stored procedure by using SqlDataReader. ExecuteReader( Probably aliases is the answer. You should use using blocks, so that you are sure that the connection, command and reader are closed correctly. Get the ID of the column being read in SqlDataReader. For Each row As DataRow In dt. cs. You should read the linked documentation if you plan to rely on this method. TechTarget and Informa Tech’s Is the best method to Retrieve data from DataReader. GetSchemaTable returns a data table with column information - but all the I don't think there's a NULL column value, when rows are returned within a datareader using the column name. true : The column is one of a set of I'm not worried about data types, just column names. GetBoolean - 42 examples found. The example above uses a string indexer, where the string is the column name from the SQL query (the table column name if you used an asterisk, *. Replace the shop by your table name and id by your column name. Commented Aug 14, 2017 at 15:21. how to read column values as C# types using the Get* methods: 5. GetValue按列名获取数据 在本文中，我们将介绍如何使用SqlDataReader. Columns() after it. SQLDataReader Row Count. Read data from SqlDataReader: 6. The following example demonstrates how to use the GetOrdinal method. How can I capture this, because i want to generate a HTML table from the rows/columns returned. Description: An Gets the name of the specified column. ColumnName i += 1 Next References. NET uses parenthesis to access the default property of an object, whereas C# uses square brackets to access the indexer property (indexers are essentially the C# equivalent of VB's default properties). use the GetOrdinal() from DataReader to get the numeric positions of a column: 4. Properties decorated with this attribute will be ignored by the mapper. I want to change column 'A' to 'a' (convert to lower case) before binding it to the grid like reader. using Microsoft. GetOrdinal("Lastname"); Note: Not related to my question but, the real reason i want to know if a column exists, because i want to know if If the query's column has an appropriate type then. Columns. My problem is that I am trying to fill a multi-dimensional array with the first row being the column header You can use OdbcDataReader. Open(); SqlCommand oCmd = new SqlCommand(sSQL, GetDataTypeName(int i): Gets the name of the data type of the specified column. Now I'm using like this, AdsCommand cmd = conn. ToString(myDateFormat) If the query's column is actually a string then see other answers. public static IEnumerable<string> GetColumnNames(this IDataReader reader) { for(int i=0; i<reader. One alternative is to use FieldCount property of datareader as given in Get number of columns in SqlDataReader based on Sam Holder's answer, you could make an extension method for that. Now assuming you know how to set up a DataReader you would do the following: using(var reader = command. Data = reader; // You cant do this. GetOrdinal(columnName)). Out of the things you're doing here, looping is the least inefficient part. GetSchemaTable including columns ColumnName, BaseColumnName and BaseTableName. Right now the data for both of the 'Name' columns are taken from the Store table. Is there an equivalent to SqlDataReader's GetInt32, GetString, GetDecimal, that takes a column name instead of an index? What's considered best practice in this case? What's fastest? Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I agree Enumerate is a better name. I have a query that gets report data via a SqlDataReader and sends the SqlDataReader to a method that exports the content out to a . GetBoolean extracted from open source projects. Rows number of SqlDataReader. var slqreaderobj = cmd. 20. //Your custom code here } UPDATE Why don't you place all the values read from the DataReader , into a list, and you can use this list afterwards for comparison between values if you need it. Quantity, StoreInventory. It returns the System. I need for PowerShell to be able to get the column names. VB. I have SqlDataReader that gets returned from a ExecuteDataReader statement. sqlDataReader reader; reader. For example , i have a table in my database and a columnname : id_declarant. You can rate examples to help us improve the quality of examples. From there if you want to refer to them by other names you can map them to a DTO or domain object with the names you want, but you'll have an easier I think that it your are searching for. GetFieldType(0); The column name is in the first column of every row. We may have properties of the class that are not data elements in the query. I have got this code which reads data from SQL DB. The class provides a property FieldCount, for the number of columns When working in ADO. Devart. SqlClient public class MainClass Shared Sub Main() Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _ "integrated security=sspi;database=MyDatabase") 'Sql Query 1 Dim sql As String ="SELECT FirstName, LastName FROM Employee; "'Create Command object Dim thisCommand As I want to retrieve decimal values from the database and I would like to know which is the recommended way to check for null values. ) It can't find "r. cursor() query = ("SELECT `name`, `ftp_name`, `created_at`, `status` AS `status_customer` FROM `customers" "WHERE `status` = %(status)s") cursor. However I will not know the number of columns present in the query result beforehand. GetOrdinal(string name): Returns the zero-based column ordinal given the column’s name. executedatareadet(); For example after data reader is returned I have two columns (A,B). From which you can interpret the column names by using a SqlCommand and DataReader. if it is because entity type configured incorrect column name then in the SQL you can see which table is trying to pull incorrect column and go to entity The following generic extension method(s) encapsulates checking if a column is null with SqlDataReader. Data I am facing 2 issues in OLEDB query (Problem 1) I need to get the column names of user uploaded excel sheet. Just edited my question with your comment question. StoreID" + " LEFT The SqlDataReader. NET that determines whether or not a SQL server database table contains an identity column and, if so, to return the name of that column. string query = "SELECT * FROM zajezd WHERE event='& Speed is somewhat of a concern I suppose. Currently I am using a try. NET data container which works the same way regardless on the specific database engine you loaded your data from. GetValue(0), or the second String sSQL = "select id, firstname, lastname from Employee"; SqlConnection oConn = new SqlConnection(sConn); oConn. StoreID, "Store. Jet. Im ultimately using this script to create a json data output and am using this script as an example. 3k 25 25 gold badges 111 111 silver badges 240 240 bronze badges. I have a table which has 23 columns. I found the solution to get the column names without having any record in the resulting relation from the sql statment: public async Task<List<string @ChristopherPisz If it was a different port then the connection string as shown wouldn't connect to it. int customerID = reader. Get column index from SqlDataReader: 3. If you do datareader["columnName"]. However, this does work: String categoryName = sqlDataReader["CategoryName"]; That is, you can refer to the column name without its table qualifier, even though the original query did include the table qualifiers. From SqlDataReader get Column Name: 3. 4. Read column by name with Get extension methods. Type of the field. I have a SqlDataReader reader, where I don't know the data structure in advance, i. GetSchemaTable(); So I have them in dt. I don't think that it's possible to omit the other column informations like ColumnOrdinal,ColumnSize,NumericPrecision and so on since you cannot use reader. That is why I call it column names, because the column values I get from this table are actually column names. GetDateTime(MyReader. FieldCount). Each column of this table describe a particular information extracted by the metadata relative to the query field Thanks, can you advice how to get COLUMN NAME from data reader also. String categoryName = sqlDataReader["Categories. FieldCount; i++) yield return reader. . If so, this should work: I am a newbie and I am trying to retrieve the Column NAme , Size ( max legth ) and DataType from some table in my database , the following code when i execute it expecting it to display all the column types and names ( i didn't find how to refer to the Size , i used ColumnSize but it is said that DataColumn does not contain a definition for this method ) but when Yes Ive been able to get the table schema a couple ways to return the columns in other test scripts, but looping on the table column names and nesting or in parallel looping on the select statement with rows does not return the output that I want. ID and b. If so, this should work: The name specified is not a valid column name. 6. Sometimes, if data exists, I can read data u The SqlDataReader. Rows For Each cell In row. For composite foreign keys <foreign key property name> becomes an underscore separated I need to find at run time, based on the result set represented by SqlDataReader, to find the name of the table for each column. Follow asked Nov 20, 2019 at 21:14. GetName(i); } SqlDataReader Get Value By Column Name (Not Ordinal Number) 0. From there if you want to refer to them by other names you can map them to a DTO or domain object with the names you want, but you'll have an easier time if your model properties are 1:1 with your column names when you go to serialize them with Dapper. I know your actual column names are in there, but I was going down the wrong path. The code initializes a two-dimensional array for storing column headers and data, retrieves column names, and populates the array with both header information and row data. Then, I want to do something like this: I need to find at run time, based on the result set represented by SqlDataReader, to find the name of the table for each column. fetchall()) use the GetOrdinal() from DataReader to get the numeric positions of a column: 3. But your loop is incorrect if you only want the column names: If you use indexes like reader. My connection string for excel is connectionString = "Provider=Microsoft. Int32' to 'System. You cannot because System. connect(databasez) cursor. Gets the column names in this collection. GetString(datareader. extensions { public static class AdonetExt { public static int GetInt32(this SqlDataReader reader, string columnName) { return reader. From there it is easy to track down why the column name did not exist. By convention, foreign key constraints are named FK_<dependent type name>_<principal type name>_<foreign key property name>. As I only want to read the data from the table, using SqlDataReader would be more efficient. SqlCommand query = new SqlCommand("SELECT Store. NET you would use SQLdr("codigo") to access the value of the column by name, in C# the equivalent would be SQLdr["codigo"]. From sql I need to get columns, tables and views names. CommandText = "SELECT a,b,c,d FROM testTable"; AdsDataReader reader = cmd. – Conrad Jagger. DataTable that describes the column metadata of the DataReader. In fact in my personal "common" library, I've now replaced the above by an extension method on IDataReader: public static IEnumerable<IDataRecord> Enumerate(this IDataReader reader) { while (reader. Query("select * from Ride Where RiderNum = 21457"); I want to be able to do the following: When r. With this attribute the column name can be customized. Net; Column Type Name; Can you get the column names from a SqlDataReader? 103. how to read column values as C# types using the Get* methods: 4. C# / CSharp Tutorial; ADO. Follow What i have tried: - Using getstring - Using index rather than column names - Specifying a specific column name - Using while (reader. How to get the DataType and Size of a column using the SqlDataReader? 1. Read) - Requesting different number of columns. The example above uses a string indexer, where the string is the SqlDataReader Get Value By Column Name (Not Ordinal Number) in C#; Verify that a column exists in the DataRow before reading its value in C#; DataRow: Select cell value by a given column name in C#. Because ordinal-based lookups are more efficient than named lookups, it is inefficient to call GetOrdinal within a loop. ToList(); So you can check if PARAMETER_NAME and PARAMETER_VALUE will be returned as expected My data source is a SqlDataReader object that contains the results of a stored proc call. Read() emailBody = emailBody + SqlDataReader objects allow you to read data in a fast forward-only manner. When selecting the fields, it doesn't include the table specifiers (r. SELECT COLUMN_NAME FROM INFORMATION_SCHEMA. {1}. 5. This method returns a DataTable object that contains information about the columns in the GetName(int i): It gets the name of the specified column. So, where in VB. SetName(i) I have Visual Studio 2013 Ultimate and creating application of WPF. – Eadel. I will not know these field names at design time. Thanks in advance. Follow answered Jul 10, 2013 at 11:48. GetName(i) I want to be able to do something like . net webapp and the result is stored in datareader. So I want to be able to do the following: var testdata = conn. {2}", reader[0], reader[1], reader[2]); listBox2. Conversely, there is a GetOrdinal which takes in a column name and returns the column index. NET. Using the methods of the SqlDataReader, I can get the value of a column by passing in it's ordinal, such as the value of the first column if I pass in read. Range(0, reader. String indexers are much more readable, making the code easier to maintain. SELECT DATA_TYPE, CHARACTER_MAXIMUM_LENGTH FROM INFORMATION_SCHEMA. To select a cell value by a given column name in C#, you can use the DataRow's Item property or the Field extension method. GetOrdinal(string) will get the column ordinal, given the name of the column. Read() Dim i As Integer For i = 0 To reader. ExecuteReader(); var columnnames = Yes, you can get the column names from a SqlDataReader using the GetSchemaTable() method. Follow answered Nov 27, 2017 at 3:03. For debugging purposes you can add the following line after you create the reader to get the names of the fields, which will be returned (statement taken from this answer): var columns = Enumerable. I don't know how should I edit it so I can use original column name and not column index. g. I also update client's data base and entity data model. I want to retrieve data by column from DataReader. It returns a DataTable where you have a row for each column returned by the query. read column values as Sql* types using the GetSql* methods: 5. I want to fill table with these data. Geting varchar width of a column that is actually used. and s. Data Imports System. Name as StoreName," + "Product. Rows[0 You can access each column of the returned row by passing the name or ordinal number of the column to the DataReader. 3. I presume you want the key of the dictionary to be the column name, and the value to be the row value. GetSchemaTable. CategoryName"]; As in, ADO. ExecuteReader() While _ExecutionResultsReader. The query below gets all the columns for a user table of a given name: Since you are using C#, it's probably easier to obtain the names from the SqlDataReader instance that is returned by ExecuteReader. Improve this question. jzmk gkh tibujmx qpevdsm mwckd lbteahmx hmkro qnyxnm tql qghwtu