OleDbAccessDaLayer.cs

// Copyright (c) 2004-2010 Azavea, Inc.
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// 
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// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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using System;
using System.Data;
using Azavea.Open.DAO.SQL;

namespace Azavea.Open.DAO.OleDb
{
    /// <summary>
    /// Implements a FastDao layer customized for PostGreSQL (optionally with PostGIS installed).
    /// </summary>
    public class OleDbAccessDaLayer : SqlDaDdlLayer
    {
        /// <summary>
        /// Construct the layer.  Should typically be called only by the appropriate
        /// ConnectionDescriptor.
        /// </summary>
        /// <param name="connDesc">Connection to the Firebird DB we'll be using.</param>
        public OleDbAccessDaLayer(OleDbDescriptor connDesc)
            : base(connDesc, true) { }

        #region Implementation of IDaDdlLayer

        /// <summary>
        /// Returns the DDL for the type of an automatically incrementing column.
        /// Some databases only store autonums in one col type so baseType may be
        /// ignored.
        /// </summary>
        /// <param name="baseType">The data type of the column (nominally).</param>
        /// <returns>The autonumber definition string.</returns>
        protected override string GetAutoType(Type baseType)
        {
            return "AUTOINCREMENT";
        }

        /// <summary>
        /// Returns the SQL type used to store a byte array in the DB.
        /// </summary>
        protected override string GetByteArrayType()
        {
            return "BLOB";
        }

        /// <summary>
        /// Returns the SQL type used to store a long in the DB.
        /// </summary>
        protected override string GetLongType()
        {
            return "BIGINT";
        }

        /// <summary>
        /// Returns the SQL type used to store a DateTime in the DB.
        /// </summary>
        protected override string GetDateTimeType()
        {
            return "DATETIME";
        }

        /// <summary>
        /// Returns the SQL type used to store a "normal" (unicode) string in the DB.
        /// </summary>
        protected override string GetStringType()
        {
            return "VARCHAR(255)";
        }

        /// <summary>
        /// Returns the SQL type used to store an ascii string in the DB.
        /// MS Access does not seem to differentiate between encodings.
        /// </summary>
        protected override string GetAsciiStringType()
        {
            return "VARCHAR(255)";
        }

        /// <summary>
        /// Returns true if you need to call "CreateStoreRoom" before storing any
        /// data.  This method is "Missing" not "Exists" because implementations that
        /// do not use a store room can return "false" from this method without
        /// breaking either a user's app or the spirit of the method.
        /// 
        /// Store room typically corresponds to "table".
        /// </summary>
        /// <returns>Returns true if you need to call "CreateStoreRoom"
        ///          before storing any data.</returns>
        public override bool StoreRoomMissing(ClassMapping mapping)
        {
            DataTable data = SqlConnectionUtilities.GetSchema(_connDesc, "Tables",
                new string[] {null, null, mapping.Table, null});
            return data.Rows.Count == 0;
        }

        #endregion
    }
}