/// <summary>
/// Create a ColumnInfo object from the data in the current JET_COLUMNLIST
/// entry.
/// </summary>
/// <param name="columnlist">The columnlist to take the data from.</param>
/// <returns>A ColumnInfo object containing the information from that record.</returns>
private ColumnInfo GetColumnInfoFromColumnlist(JET_COLUMNLIST columnlist)
{
string name = Api.RetrieveColumnAsString(
this.sesid,
columnlist.tableid,
columnlist.columnidcolumnname,
NativeMethods.Encoding,
RetrieveColumnGrbit.None);
var columnidValue = (uint)Api.RetrieveColumnAsUInt32(this.sesid, columnlist.tableid, columnlist.columnidcolumnid);
var coltypValue = (uint)Api.RetrieveColumnAsUInt32(this.sesid, columnlist.tableid, columnlist.columnidcoltyp);
uint codepageValue = (ushort)Api.RetrieveColumnAsUInt16(this.sesid, columnlist.tableid, columnlist.columnidCp);
var maxLength = (uint)Api.RetrieveColumnAsUInt32(this.sesid, columnlist.tableid, columnlist.columnidcbMax);
byte[] defaultValue = Api.RetrieveColumn(this.sesid, columnlist.tableid, columnlist.columnidDefault);
var grbitValue = (uint)Api.RetrieveColumnAsUInt32(this.sesid, columnlist.tableid, columnlist.columnidgrbit);
return(new ColumnInfo(
name,
new JET_COLUMNID()
{
Value = columnidValue
},
(JET_coltyp)coltypValue,
(JET_CP)codepageValue,
checked ((int)maxLength),
defaultValue,
(ColumndefGrbit)grbitValue));
}
/// <summary>
/// Create a ColumnInfo object from the data in the current JET_COLUMNLIST entry.
/// </summary>
/// <param name="sesid">The session to use.</param>
/// <param name="columnlist">The columnlist to take the data from.</param>
/// <returns>A ColumnInfo object containing the information from that record.</returns>
private static ColumnInfo GetColumnInfoFromColumnlist(JET_SESID sesid, JET_COLUMNLIST columnlist)
{
// As of Sep 2015, JetGetColumnInfoW is only called for Win8+. Even though Unicode should have
// worked in Win7, it wasn't reliable until Win8.
Encoding encodingOfTextColumns = EsentVersion.SupportsWindows8Features ? Encoding.Unicode : LibraryHelpers.EncodingASCII;
string name = Api.RetrieveColumnAsString(
sesid,
columnlist.tableid,
columnlist.columnidcolumnname,
encodingOfTextColumns,
RetrieveColumnGrbit.None);
name = StringCache.TryToIntern(name);
var columnidValue = (uint)Api.RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidcolumnid);
var coltypValue = (uint)Api.RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidcoltyp);
uint codepageValue = (ushort)Api.RetrieveColumnAsUInt16(sesid, columnlist.tableid, columnlist.columnidCp);
var maxLength = (uint)Api.RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidcbMax);
byte[] defaultValue = Api.RetrieveColumn(sesid, columnlist.tableid, columnlist.columnidDefault);
var grbitValue = (uint)Api.RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidgrbit);
return(new ColumnInfo(
name,
new JET_COLUMNID {
Value = columnidValue
},
(JET_coltyp)coltypValue,
(JET_CP)codepageValue,
unchecked ((int)maxLength),
defaultValue,
(ColumndefGrbit)grbitValue));
}
public void ConvertColumnlistFromNative()
{
var tableid = new JET_TABLEID { Value = (IntPtr)0x1000 };
var col1 = new JET_COLUMNID { Value = 1 };
var col2 = new JET_COLUMNID { Value = 2 };
var col3 = new JET_COLUMNID { Value = 3 };
var col4 = new JET_COLUMNID { Value = 4 };
var col5 = new JET_COLUMNID { Value = 5 };
var col6 = new JET_COLUMNID { Value = 6 };
var col7 = new JET_COLUMNID { Value = 7 };
var native = new NATIVE_COLUMNLIST()
{
tableid = tableid.Value,
cRecord = 100,
columnidcolumnname = col1.Value,
columnidcolumnid = col2.Value,
columnidcoltyp = col3.Value,
columnidCp = col4.Value,
columnidcbMax = col5.Value,
columnidgrbit = col6.Value,
columnidDefault = col7.Value,
};
var columnlist = new JET_COLUMNLIST();
columnlist.SetFromNativeColumnlist(native);
Assert.AreEqual(tableid, columnlist.tableid);
Assert.AreEqual(100, columnlist.cRecord);
Assert.AreEqual(col1, columnlist.columnidcolumnname);
Assert.AreEqual(col2, columnlist.columnidcolumnid);
Assert.AreEqual(col3, columnlist.columnidcoltyp);
Assert.AreEqual(col4, columnlist.columnidCp);
Assert.AreEqual(col5, columnlist.columnidcbMax);
Assert.AreEqual(col6, columnlist.columnidgrbit);
Assert.AreEqual(col7, columnlist.columnidDefault);
}
/// <summary>
/// Create a ColumnInfo object from the data in the current JET_COLUMNLIST
/// entry.
/// </summary>
/// <param name="sesid">The session to use.</param>
/// <param name="columnlist">The columnlist to take the data from.</param>
/// <returns>A ColumnInfo object containing the information from that record.</returns>
private static ColumnInfo GetColumnInfoFromColumnlist(JET_SESID sesid, JET_COLUMNLIST columnlist)
{
string name = RetrieveColumnAsString(
sesid,
columnlist.tableid,
columnlist.columnidcolumnname,
NativeMethods.Encoding,
RetrieveColumnGrbit.None);
var columnidValue = (uint) RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidcolumnid);
var coltypValue = (uint) RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidcoltyp);
uint codepageValue = (ushort) RetrieveColumnAsUInt16(sesid, columnlist.tableid, columnlist.columnidCp);
var maxLength = (uint) RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidcbMax);
byte[] defaultValue = RetrieveColumn(sesid, columnlist.tableid, columnlist.columnidDefault);
var grbitValue = (uint) RetrieveColumnAsUInt32(sesid, columnlist.tableid, columnlist.columnidgrbit);
return new ColumnInfo(
name,
new JET_COLUMNID() { Value = columnidValue },
(JET_coltyp) coltypValue,
(JET_CP) codepageValue,
checked((int) maxLength),
defaultValue,
(ColumndefGrbit) grbitValue);
}
/// <summary>
/// Iterates over the information in the JET_COLUMNLIST, returning information about each column.
/// The table in the columnlist is closed when finished.
/// </summary>
/// <param name="sesid">The session to use.</param>
/// <param name="columnlist">The columnlist to iterate over.</param>
/// <returns>An iterator over ColumnInfo for each column described in the JET_COLUMNLIST.</returns>
private static IEnumerable<ColumnInfo> EnumerateColumnInfos(JET_SESID sesid, JET_COLUMNLIST columnlist)
{
try
{
MoveBeforeFirst(sesid, columnlist.tableid);
while (TryMoveNext(sesid, columnlist.tableid))
{
yield return GetColumnInfoFromColumnlist(sesid, columnlist);
}
}
finally
{
// Close the temporary table used to return the results
JetCloseTable(sesid, columnlist.tableid);
}
}
/// <summary>
/// Retrieves information about all columns in a table.
/// </summary>
/// <param name="sesid">The session to use.</param>
/// <param name="dbid">The database that contains the table.</param>
/// <param name="tablename">The name of the table containing the column.</param>
/// <param name="columnName">This parameter is ignored.</param>
/// <param name="columnlist">Filled in with information about the columns in the table.</param>
public static void JetGetColumnInfo(
JET_SESID sesid,
JET_DBID dbid,
string tablename,
string columnName,
out JET_COLUMNLIST columnlist)
{
Api.Check(Impl.JetGetColumnInfo(sesid, dbid, tablename, columnName, out columnlist));
}
/// <summary>
/// Retrieves information about all columns in the table.
/// </summary>
/// <param name="sesid">The session to use.</param>
/// <param name="tableid">The table containing the column.</param>
/// <param name="columnName">The parameter is ignored.</param>
/// <param name="columnlist">Filled in with information about the columns in the table.</param>
public static void JetGetTableColumnInfo(
JET_SESID sesid,
JET_TABLEID tableid,
string columnName,
out JET_COLUMNLIST columnlist)
{
Api.Check(Impl.JetGetTableColumnInfo(sesid, tableid, columnName, out columnlist));
}
/// <summary>
/// Iterates over the information in the JET_COLUMNLIST, returning information about each column.
/// The table in the columnlist is closed when finished.
/// </summary>
/// <param name="sesid">The session to use.</param>
/// <param name="columnlist">The columnlist to iterate over.</param>
/// <returns>An iterator over ColumnInfo for each column described in the JET_COLUMNLIST.</returns>
private static IEnumerable <ColumnInfo> EnumerateColumnInfos(JET_SESID sesid, JET_COLUMNLIST columnlist)
{
try
{
if (Api.TryMoveFirst(sesid, columnlist.tableid))
{
do
{
yield return(GetColumnInfoFromColumnlist(sesid, columnlist));
}while (Api.TryMoveNext(sesid, columnlist.tableid));
}
}
finally
{
// Close the temporary table used to return the results
JetCloseTable(sesid, columnlist.tableid);
}
}
/// <summary>
/// Creates a <see cref="ColumnDefinition"/> object representing the column passed in by <paramref name="columnList"/>.
/// </summary>
/// <param name="database">The database.</param>
/// <param name="tableName">Name of the table.</param>
/// <param name="columnList">The <see cref="JET_COLUMNLIST"/> object that represents the row in
/// the temptable for this particular column.</param>
/// <returns>
/// A <see cref="ColumnDefinition"/> object based on the current row in the temptable
/// represented by <paramref name="columnList"/>.
/// </returns>
internal static ColumnDefinition Load(IsamDatabase database, string tableName, JET_COLUMNLIST columnList)
{
lock (database.IsamSession)
{
using (IsamTransaction trx = new IsamTransaction(database.IsamSession))
{
// load info for the column
ColumnDefinition columnDefinition = new ColumnDefinition();
JET_SESID sesid = database.IsamSession.Sesid;
// If we use the wide API (Vista+), then the temp table will be in UTF-16.
// Technically, this should have worked in Vista. But there was a bug, and
// it was fixed after Windows 7.
Encoding encodingOfTextColumns = EsentVersion.SupportsWindows8Features
? Encoding.Unicode
: Encoding.ASCII;
string columnName = Api.RetrieveColumnAsString(
database.IsamSession.Sesid,
columnList.tableid,
columnList.columnidcolumnname,
encodingOfTextColumns);
JET_COLUMNBASE columnbase;
Api.JetGetColumnInfo(database.IsamSession.Sesid, database.Dbid, tableName, columnName, out columnbase);
columnDefinition.columnid = new Columnid(columnbase);
columnDefinition.name = columnDefinition.columnid.Name;
columnDefinition.type = columnDefinition.columnid.Type;
ColumndefGrbit grbitColumn = (ColumndefGrbit)Api.RetrieveColumnAsUInt32(sesid, columnList.tableid, columnList.columnidgrbit).GetValueOrDefault();
columnDefinition.flags = ColumnFlagsFromGrbits(grbitColumn);
columnDefinition.maxLength = Api.RetrieveColumnAsInt32(sesid, columnList.tableid, columnList.columnidcbMax).GetValueOrDefault();
columnDefinition.IsAscii = columnbase.cp == JET_CP.ASCII;
byte[] defaultValueBytes = Api.RetrieveColumn(sesid, columnList.tableid, columnList.columnidDefault);
Columnid isamColumnid = columnDefinition.columnid;
columnDefinition.defaultValue = Converter.ObjectFromBytes(
isamColumnid.Coltyp,
columnDefinition.IsAscii,
defaultValueBytes);
columnDefinition.ReadOnly = true;
return columnDefinition;
}
}
}
public void JetColumnlistToString()
{
var value = new JET_COLUMNLIST { cRecord = 3, tableid = new JET_TABLEID { Value = (IntPtr)0x1a } };
Assert.AreEqual("JET_COLUMNLIST(0x1a,3 records)", value.ToString());
}
