连接Oracle数据库的OracleHelper.cs

时间：2022-03-10 17:01
  
    
    using 
System;
using 
System.Configuration;
using 
System.Data;
using 
System.Data.OracleClient;
using 
System.Collections;
 
namespace 
DBUtility {
 
    /// <summary>
    /// A helper class used to execute queries against an Oracle database
    /// </summary>
    public 
abstract class OracleHelper {
 
        //Create a hashtable for the parameter cached
        private 
static Hashtable parmCache = Hashtable.Synchronized(new 
Hashtable());
 
        /// <summary>
        /// Execute a database query which does not include a select
        /// </summary>
        /// <param name="connString">Connection string to database</param>
        /// <param name="cmdType">Command type either stored procedure or SQL</param>
        /// <param name="cmdText">Acutall SQL Command</param>
        /// <param name="commandParameters">Parameters to bind to the command</param>
        /// <returns></returns>
        public 
static int ExecuteNonQuery(string 
connectionString, CommandType cmdType, string 
cmdText, params 
OracleParameter[] commandParameters) {
            // Create a new Oracle command
            OracleCommand cmd = new 
OracleCommand();
 
            //Create a connection
            using 
(OracleConnection connection = new 
OracleConnection(connectionString)) {
 
                //Prepare the command
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
 
                //Execute the command
                int 
val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return 
val;
            }
        }
 
        /// <summary>
        /// Execute an OracleCommand (that returns no resultset) against an existing database transaction 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));
        /// </remarks>
        /// <param name="trans">an existing database transaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public 
static int ExecuteNonQuery(OracleTransaction trans, CommandType cmdType, string 
cmdText, params 
OracleParameter[] commandParameters) {
            OracleCommand cmd = new 
OracleCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
            int 
val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return 
val;
        }
 
        /// <summary>
        /// Execute an OracleCommand (that returns no resultset) against an existing database connection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));
        /// </remarks>
        /// <param name="conn">an existing database connection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public 
static int ExecuteNonQuery(OracleConnection connection, CommandType cmdType, string 
cmdText, params 
OracleParameter[] commandParameters) {
 
            OracleCommand cmd = new 
OracleCommand();
 
            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            int 
val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return 
val;
        }
 
        /// <summary>
        /// Execute a select query that will return a result set
        /// </summary>
        /// <param name="connString">Connection string</param>
        //// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns></returns>
        public 
static OracleDataReader ExecuteReader(string 
connectionString, CommandType cmdType, string 
cmdText, params 
OracleParameter[] commandParameters) {
 
            //Create the command and connection
            OracleCommand cmd = new 
OracleCommand();
            OracleConnection conn = new 
OracleConnection(connectionString);
 
            try 
{
                //Prepare the command to execute
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
 
                //Execute the query, stating that the connection should close when the resulting datareader has been read
                OracleDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return 
rdr;
 
            }
            catch 
{
 
                //If an error occurs close the connection as the reader will not be used and we expect it to close the connection
                conn.Close();
                throw;
            }
        }
 
        /// <summary>
        /// Execute an OracleCommand that returns the first column of the first record against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
        public 
static object ExecuteScalar(string 
connectionString, CommandType cmdType, string 
cmdText, params 
OracleParameter[] commandParameters) {
            OracleCommand cmd = new 
OracleCommand();
 
            using 
(OracleConnection conn = new 
OracleConnection(connectionString)) {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                object 
val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return 
val;
            }
        }
 
        /// <summary>
        /// Execute a OracleCommand (that returns a 1x1 resultset)  against the specified SqlTransaction
        /// using the provided parameters.
        /// </summary>
        /// <param name="transaction">A   valid SqlTransaction</param>
        /// <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">The stored procedure name   or PL/SQL command</param>
        /// <param name="commandParameters">An array of   OracleParamters used to execute the command</param>
        /// <returns>An   object containing the value in the 1x1 resultset generated by the command</returns>
        public 
static object ExecuteScalar(OracleTransaction transaction, CommandType commandType, string 
commandText, params 
OracleParameter[] commandParameters) {
            if(transaction == null)
                throw 
new ArgumentNullException("transaction");
            if(transaction != null 
&& transaction.Connection == null)
                throw 
new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
 
            // Create a command and prepare it for execution
            OracleCommand cmd = new 
OracleCommand();
 
            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
 
            // Execute the command & return the results
            object 
retval = cmd.ExecuteScalar();
 
            // Detach the SqlParameters from the command object, so they can be used again
            cmd.Parameters.Clear();
            return 
retval;
        }
 
        /// <summary>
        /// Execute an OracleCommand that returns the first column of the first record against an existing database connection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  Object obj = ExecuteScalar(conn, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));
        /// </remarks>
        /// <param name="conn">an existing database connection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
        public 
static object ExecuteScalar(OracleConnection connectionString, CommandType cmdType, string 
cmdText, params 
OracleParameter[] commandParameters) {
            OracleCommand cmd = new 
OracleCommand();
 
            PrepareCommand(cmd, connectionString, null, cmdType, cmdText, commandParameters);
            object 
val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return 
val;
        }
 
        /// <summary>
        /// Add a set of parameters to the cached
        /// </summary>
        /// <param name="cacheKey">Key value to look up the parameters</param>
        /// <param name="commandParameters">Actual parameters to cached</param>
        public 
static void CacheParameters(string 
cacheKey, params 
OracleParameter[] commandParameters) {
            parmCache[cacheKey] = commandParameters;
        }
 
        /// <summary>
        /// Fetch parameters from the cache
        /// </summary>
        /// <param name="cacheKey">Key to look up the parameters</param>
        /// <returns></returns>
        public 
static OracleParameter[] GetCachedParameters(string 
cacheKey) {
            OracleParameter[] cachedParms = (OracleParameter[])parmCache[cacheKey];
 
            if 
(cachedParms == null)
                return 
null;
 
            // If the parameters are in the cache
            OracleParameter[] clonedParms = new 
OracleParameter[cachedParms.Length];
 
            // return a copy of the parameters
            for 
(int 
i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms[i] = (OracleParameter)((ICloneable)cachedParms[i]).Clone();
 
            return 
clonedParms;
        }
 
        /// <summary>
        /// Internal function to prepare a command for execution by the database
        /// </summary>
        /// <param name="cmd">Existing command object</param>
        /// <param name="conn">Database connection object</param>
        /// <param name="trans">Optional transaction object</param>
        /// <param name="cmdType">Command type, e.g. stored procedure</param>
        /// <param name="cmdText">Command test</param>
        /// <param name="commandParameters">Parameters for the command</param>
        private 
static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, CommandType cmdType, string 
cmdText, OracleParameter[] commandParameters) {
 
            //Open the connection if required
            if 
(conn.State != ConnectionState.Open)
                conn.Open();
 
            //Set up the command
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            cmd.CommandType = cmdType;
 
            //Bind it to the transaction if it exists
            if 
(trans != null)
                cmd.Transaction = trans;
 
            // Bind the parameters passed in
            if 
(commandParameters != null) {
                foreach 
(OracleParameter parm in 
commandParameters)
                    cmd.Parameters.Add(parm);
            }
        }
 
        /// <summary>
        /// Converter to use boolean data type with Oracle
        /// </summary>
        /// <param name="value">Value to convert</param>
        /// <returns></returns>
        public 
static string OraBit(bool 
value) {
            if(value)
                return 
"Y";
            else
                return 
"N";
        }
 
        /// <summary>
        /// Converter to use boolean data type with Oracle
        /// </summary>
        /// <param name="value">Value to convert</param>
        /// <returns></returns>
        public 
static bool OraBool(string 
value) {
            if(value.Equals("Y"))
                return 
true;
            else
                return 
false;
        } 
    }
}