I've got 2 datatables and am trying to summarize the data in them using a left outer join. The join works fine with this code
Dim Journal = From entries In dt.AsEnumerable()
Join inccodes In dtGL.AsEnumerable()
On entries.Field(Of String)("GLCode") Equals inccodes.Field(Of String)("GLCode")
Group By keys = New With {Key .IncomeCode = entries.Field(Of String)("GLCode"), Key .IncomeDesc = .inccodes.Field(Of String)("GLCodeDesc")}
Into ChargeSum = Group, sm = Sum(entries.Field(Of Decimal)("Amount"))
Where sm <> 0
Select New GL_Journal With {.IncomeCode = keys.IncomeCode, .IncomeDesc = keys.IncomeDesc, .LineAmount = sm}
`
However, since I really want a Left Outer Join I want to use Group Join instead of Join.
As soon as I change the Join to Group Join the code in the Group by at ".inccodes.field(Of String)("GLCodeDesc")" has ".inccodes" highlighted with the error "'inccodes' is not a member of 'anonymous type'"
I've reviewed much documentation on Group By and Group Join but there is scant information on them together.
Any ideas? Would I have more options/success with the method syntax?
If i try to reproduce your query using a left outer join, I will do something like this :
Dim dt As New DataTable
dt.Columns.Add("GLCode", GetType(String))
dt.Columns.Add("Amount", GetType(Decimal))
dt.Rows.Add("111", 3251.21)
dt.Rows.Add("222", 125.79)
dt.Rows.Add("999", 10000)
Dim dtGL As New DataTable
dtGL.Columns.Add("GLCode", GetType(String))
dtGL.Columns.Add("GLCodeDesc", GetType(String))
dtGL.Rows.Add("111", "a")
dtGL.Rows.Add("222", "b")
dtGL.Rows.Add("333", "c")
Dim Journal = From entries In dt.AsEnumerable()
Group Join inccodes In dtGL.AsEnumerable()
On entries.Field(Of String)("GLCode") Equals inccodes.Field(Of String)("GLCode")
Into Group
From lj In Group.DefaultIfEmpty()
Group By keys = New With {Key .IncomeCode = entries.Field(Of String)("GLCode"), Key .IncomeDesc = lj?.Field(Of String)("GLCodeDesc")}
Into ChargeSum = Group, sm = Sum(entries.Field(Of Decimal)("Amount"))
Select New With {.IncomeCode = keys.IncomeCode, .IncomeDesc = keys.IncomeDesc, .LineAmount = sm}
I am having some issues with trying to figure out the correct way, or syntax, to join/concatenate a series of "name" columns from a separate table into a query.
Currently I am testing in LINQpad using two queries; the first returns all the master data that I use for other background work, and the second is a user-friendly version that I bind to a DGV. The issue comes in when I try to join the Physicians names like I do for a separate combobox.
This is what I have thus far - while it does return the Physician's name, it will NOT return the name if the TITLE field is NULL on the Physicians table.
Dim query1 = (From demog In data_Demogs
From MedHist In data_Demog_MedHists.where(Function(a) demog.ID_Demog = a.ID_Demog).defaultifempty
From BGLAssay In data_Demog_BGLs.where(Function(a) demog.ID_Demog = a.ID_Demog).defaultifempty
Select
demog.ID_Demog,
demog.Last_Name,
demog.First_Name,
demog.ID_Demog_AKA,
demog.DOB,
demog.Gender,
demog.ST_Complete,
demog.LT_Complete,
demog.LT_Due_Date,
demog.ID_Physician,
demog.ID_Reason_For_Call,
demog.Intl_Patient,
demog.Mayo_Patient,
MedHist.ID_Disease_Group,
MedHist.ID_Disease_Type,
BGLAssay.ID_BGL_Assay)
Dim query2 = (From items In query1
From demogAKA In data_Demogs.Where(Function(a) items.ID_Demog = a.ID_Demog_AKA).defaultifempty
From DType In tbl_Disease_Types.Where(Function(a) items.ID_Disease_Type = a.ID_Disease_Type).defaultifempty
From DGroup In tbl_Disease_Groups.Where(Function(a) items.ID_Disease_Group = a.ID_Disease_Group).defaultifempty
From RFC In tbl_Reason_For_Calls.Where(Function(a) items.ID_Reason_For_Call = a.ID_Reason_For_Call).defaultifempty
From Phys In tbl_Physicians.Where(Function(a) items.ID_Physician = a.ID_Physician).defaultifempty
From Title In tbl_Titles.Where(Function(a) Phys.ID_Title = a.ID_Title).defaultifempty
Select
items.ID_Demog,
items.Last_Name,
items.First_Name,
AKA_Name = demogAKA.Last_Name + ", " + demogAKA.First_Name,
items.DOB,
items.Gender,
items.ST_Complete,
items.LT_Complete,
items.LT_Due_Date,
DType.Disease_Type_Abr,
DGroup.Disease_Group_Name,
RFC.Reason_For_Call,
items.ID_Physician,
Phys_Name = Phys.Last_Name + ", " + Phys.First_Name + ", " + Title.Title
).distinct
console.writeline(Query2)
This is the currently query I for a combobox that DOES bring back all names, joining those names even if a field is NULL.
Dim Phys = (From e In tbl_Physicians
Group Join f In tbl_Titles On e.ID_Title Equals f.ID_Title
Into Matched = Group
From m In Matched.DefaultIfEmpty()
Select e.ID_Physician,
e.Last_Name,
e.First_Name,
e.Middle_Initial,
m.Title
).ToArray().Select(Function(item) New With {
.ID = item.ID_Physician,
.Phys_Name = (String.Join(", ",
String.Join(",",
New String() {item.Last_Name, item.First_Name, item.Title}).Split(
New Char() {","}, System.StringSplitOptions.RemoveEmptyEntries)))
})
Console.writeline(Phys)
When I try to add a third query to return just the Physician's name, and join that to the final query, I get the following error:
Local sequence cannot be used in LINQ to SQL implementations of query operators except the Contains operator.
'Query 1 removed to save space
Dim PhysNames = (From e In tbl_Physicians
Group Join f In tbl_Titles On e.ID_Title Equals f.ID_Title
Into Matched = Group
From m In Matched.DefaultIfEmpty()
Select e.ID_Physician,
e.Last_Name,
e.First_Name,
e.Middle_Initial,
m.Title
).ToArray().Select(Function(item) New With {
.ID = item.ID_Physician,
.Phys_Name = (String.Join(", ",
String.Join(",",
New String() {item.Last_Name, item.First_Name, item.Title}).Split(
New Char() {","}, System.StringSplitOptions.RemoveEmptyEntries)))
})
Dim query2 = (From items In query1
From demogAKA In data_Demogs.Where(Function(a) items.ID_Demog = a.ID_Demog_AKA).defaultifempty
From DType In tbl_Disease_Types.Where(Function(a) items.ID_Disease_Type = a.ID_Disease_Type).defaultifempty
From DGroup In tbl_Disease_Groups.Where(Function(a) items.ID_Disease_Group = a.ID_Disease_Group).defaultifempty
From RFC In tbl_Reason_For_Calls.Where(Function(a) items.ID_Reason_For_Call = a.ID_Reason_For_Call).defaultifempty
From Phys In PhysNames.Where(Function(a) items.ID_Physician = a.ID).defaultifempty
Select
items.ID_Demog,
items.Last_Name,
items.First_Name,
AKA_Name = demogAKA.Last_Name + ", " + demogAKA.First_Name,
items.DOB,
items.Gender,
items.ST_Complete,
items.LT_Complete,
items.LT_Due_Date,
DType.Disease_Type_Abr,
DGroup.Disease_Group_Name,
RFC.Reason_For_Call,
items.ID_Physician,
Phys.Phys_Name
).distinct
console.writeline(Query2)
When I try to join my working query into the final query, I get the following error:
Invalid cast from 'System.String' to 'VB$AnonymousDelegate_0`2[[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934...
'Query1 removed to save space
Dim query2 = (From items In query1
From demogAKA In data_Demogs.Where(Function(a) items.ID_Demog = a.ID_Demog_AKA).defaultifempty
From DType In tbl_Disease_Types.Where(Function(a) items.ID_Disease_Type = a.ID_Disease_Type).defaultifempty
From DGroup In tbl_Disease_Groups.Where(Function(a) items.ID_Disease_Group = a.ID_Disease_Group).defaultifempty
From RFC In tbl_Reason_For_Calls.Where(Function(a) items.ID_Reason_For_Call = a.ID_Reason_For_Call).defaultifempty
From Phys In tbl_Physicians
Where items.ID_Physician = Phys.ID_Physician
Group Join f In tbl_Titles On Phys.ID_Title Equals f.ID_Title
Into Matched = Group
From m In Matched.DefaultIfEmpty()
Select
items.ID_Demog,
items.Last_Name,
items.First_Name,
AKA_Name = demogAKA.Last_Name + ", " + demogAKA.First_Name,
items.DOB,
items.Gender,
items.ST_Complete,
items.LT_Complete,
items.LT_Due_Date,
DType.Disease_Type_Abr,
DGroup.Disease_Group_Name,
RFC.Reason_For_Call,
items.ID_Physician,
PhysName = Function(a) String.Join(", ",
String.Join(",",
New String() {Phys.Last_Name, Phys.First_Name, m.Title}).Split(
New Char() {","}, System.StringSplitOptions.RemoveEmptyEntries))
).distinct
console.writeline(Query2)
After a long time playing around in LINQpad, and then finally re-reading JM's answer to a former question I had, I realized what I was doing wrong.
As per his post:
The problem is that, while LINQ in general has no issue with that code, LINQ to Entities does. LINQ syntax is the same for every provider but the implementation under the hood differs and, in the case of LINQ to Entities, your LINQ code has to translated to SQL and, in this case, there's no mapping from String.Join to SQL. That code would work fine with LINQ to Objects so one solution is to push that operation out of the original query and into a LINQ to Objects query. That would mean selecting the raw data with your LINQ to Entities query, calling ToList or ToArray on the result to materialise the query, then performing another query on that result. That second query will be LINQ to Objects rather than LINQ to Entities and so String.Join will not be an issue.
So... Once I realized I needed to push out the String.Join, I ended up with the following code:
Dim DispList = (From items In MastList
From demogAKA In dbACL.data_Demog.Where(Function(a) items.ID_Demog = a.ID_Demog_AKA).DefaultIfEmpty
From DType In dbACL.tbl_Disease_Type.Where(Function(a) items.ID_Disease_Type = a.ID_Disease_Type).DefaultIfEmpty
From DGroup In dbACL.tbl_Disease_Group.Where(Function(a) items.ID_Disease_Group = a.ID_Disease_Group).DefaultIfEmpty
From RFC In dbACL.tbl_Reason_For_Call.Where(Function(a) items.ID_Reason_For_Call = a.ID_Reason_For_Call).DefaultIfEmpty
From e In dbACL.tbl_Physician.Where(Function(a) items.ID_Physician = a.ID_Physician).DefaultIfEmpty
Group Join f In dbACL.tbl_Title On e.ID_Title Equals f.ID_Title
Into Matched = Group
From m In Matched.DefaultIfEmpty()
Select
items.ID_Demog,
items.Last_Name,
items.First_Name,
AKALname = demogAKA.Last_Name,
AKAFname = demogAKA.First_Name,
items.DOB,
items.Gender,
items.ST_Complete,
items.LT_Complete,
items.LT_Due_Date,
DType.Disease_Type_Abr,
DGroup.Disease_Group_Name,
RFC.Reason_For_Call,
items.ID_Physician,
PLName = e.Last_Name,
PFname = e.First_Name,
PMI = e.Middle_Initial,
PTitle = m.Title
).Distinct.ToList().Select(Function(a) New With {
a.ID_Demog,
a.Last_Name,
a.First_Name,
.AKA_Name = (String.Join(", ",
String.Join(",",
New String() {a.AKALname, a.AKAFname}).Split(
New Char() {","}, System.StringSplitOptions.RemoveEmptyEntries))),
a.DOB,
a.Gender,
a.ST_Complete,
a.LT_Complete,
a.LT_Due_Date,
a.Disease_Type_Abr,
a.Disease_Group_Name,
a.Reason_For_Call,
a.ID_Physician,
.PName = (String.Join(", ",
String.Join(",",
New String() {a.PLName, a.PFname, a.PTitle}).Split(
New Char() {","}, System.StringSplitOptions.RemoveEmptyEntries)))
}).ToList()
I have 2 tables: pob (with results of some activities) and names (with user data). I try to select top 5 users from table pob based on their last activity date. So I inner join names and pob, then select top 5 users based on calculated max(date).
This query is working:
SELECT TOP 5
[u].[id],
[u].[name],
max([p].[date]) As LastDateOfUse,
FROM
[pob] [p]
INNER JOIN
[users] [u]
ON
[p].[id_name] = [u].[id]
WHERE
[p].[date] >= #2017-01-01#
GROUP BY
[u].[id],
[u].[name]
ORDER BY
max([p].[date]) DESC
Now I need to transform it into Linq query. This my attempt but it's not working.
"Key" is not a member of type "System.Collections.Generic.IEnumerable'1[VB$AnonymousType_2'2[pob,users]]".
Using db = New DbContext() With {.InlineParameters = True}
Dim query1 = From p In db.pob
Join u In db.users On p.id_name Equals u.id
Where p.date >= New Date(2017, 1, 1)
Group New With {p, u} By pu = New With {Key u.id, Key u.name} Into pg = Group
Select New RecentUser With
{
.id = pu.id,
.name = pu.name,
.LastDateOfUse = pg.Max(Function(f) f.p.date)
}
query1 = query1.OrderByDescending(Function(f) f.LastDateOfUse).Take(5)
Return query1.ToList
End Using
If I remove .LastDateOfUse = pg.Max(Function(f) f.p.Date) like below it works. By 'works' I mean there is no exception but of course result of query is wrong however grouping is done properly.
Using db = New DbContext() With {.InlineParameters = True}
Dim query1 = From p In db.pob
Join u In db.users On p.id_name Equals u.id
Where p.date >= New Date(2017, 1, 1)
Group New With {p, u} By pu = New With {Key u.id, Key u.name} Into pg = Group
Select New RecentUser With
{
.id = pu.id,
.name = pu.name
}
Return query1.ToList
End Using
Edit
I also tried going through navigation properties like below, but again I receive the same error.
Using db = New DbContext() With {.InlineParameters = True}
Dim query1 = From p In db.pob
Where p.date >= New Date(2017, 1, 1)
Group p By pu = New With {Key u.User.id, Key u.User.name} Into pg = Group
Select New RecentUser With
{
.id = pu.id,
.name = pu.name
.LastDateOfUse = pg.Max(Function(f) f.date)
}
query1 = query1.OrderByDescending(Function(f) f.LastDateOfUse).Take(5)
Return query1.ToList
End Using
And again if I remove .LastDateOfUse = pg.Max(Function(f) f.p.Date) like below it starts to work (proper grouping, wrong overall result).
Using db = New DbContext() With {.InlineParameters = True}
Dim query1 = From p In db.pob
Where p.date >= New Date(2017, 1, 1)
Group p By pu = New With {Key u.User.id, Key u.User.name} Into pg = Group
Select New RecentUser With
{
.id = pu.id,
.name = pu.name
}
Return query1.ToList
End Using
How can I transform above Sql query to Linq? (preferable answer in VB.Net but C# is ok too)
Solution
There is no solution yet. It looks like VB has bad Linq queries resolver - it creates unexpected method chain that can not be converted to SQL.
So instead
Group By ... Into pg = Group
we need
Group By ... Into LastDateOfUse = p.Max(Function(f) f.date).
See below full query.
Using db = New DbContext() With {.InlineParameters = True}
Dim query1 = From p In db.pob
Where p.date >= New Date(2017, 1, 1)
Group p By pu = New With {Key u.User.id, Key u.User.name} Into LastDateOfUse = p.Max(Function(f) f.date)
Select New RecentUser With
{
.id = pu.id,
.name = pu.name
.LastDateOfUse = LastDateOfUse
}
Return query1.ToList
End Using
Another problem with lambda syntax
Using lambda syntax we receive another exception.
Dim query = db.pob.
Where(Function(f) f.date >= New Date(2017, 1, 1).
GroupBy(Function(f) New With
{
Key .userid= f.user.id,
Key .username = f.user.name
}).Select(Function(f) New RecentUser With
{
.id = f.Key.userid,
.name = f.Key.username,
.LastDateOfUse = f.Max(Function(g) g.date)
}).ToList
Exception
VB.NET compiler adds unnecessary Convert to IEnumerable when generating Expression Tree.
An unhandled exception of type LinqToDB.Linq.LinqException occurred in linq2db.dll
Convert(f).Select(g => g.Date).Max() cannot be converted to SQL
GitHub
I posted an issue here.
Svyatoslav Danyliv based on my issue opened his own here.
I want to use join in Oracle 8i. I have my query as below.
I have this query of getting data from two tables using an join, but I get the error SQL command not properly ended.
private List<StamfordProdRelease> GetStamfordProdReleases()
{
List<StamfordProdRelease> list = null;
string srtQry = "SELECT NVL(NULL, 0) ID," +
" DLOG.RELEASEID AS RELEASE_BUILD," +
" TRUNC (DLOGDET.DEPLOYDATE) AS PROD_DEPLOY_DATE," +
" DLOGDET.DEPLOYREQUEST AS BAAR_RFD," +
" DLOG.FILENAMEEXT_VC AS SCRIPT_NAME," +
" DLOG.VERSION," +
" DLOG.REQUEST," +
" DLOG.NOTE AS COMMENTS" +
" FROM ADM_DEPLOYMENTLOGDETAIL DLOGDET" +
" JOIN ADM_DEPLOYMENTLOG DLOG ON DLOG.LOGNO = DLOGDET.LOGNO;";
using (OracleConnection conn = new OracleConnection(Globals.Constants.AppConnectionStringReadOnly))
{
using (OracleCommand objCommand = new OracleCommand(srtQry, conn))
{
objCommand.CommandType = CommandType.Text;
DataTable dt = new DataTable();
OracleDataAdapter adp = new OracleDataAdapter(objCommand);
conn.Open();
adp.Fill(dt);
if (dt != null)
{
list = ConvertToStamfordProdRelease(dt).ToList();
}
}
}
return list;
}
My target is to insert records into a table.
Keep everything in one set of " and also you only need a single ; to end the SQL query outside of the double quotes.
private List<StamfordProdRelease> GetStamfordProdReleases()
{
List<StamfordProdRelease> list = null;
string srtQry = "SELECT NVL(NULL, 0) ID,
DLOG.RELEASEID AS RELEASE_BUILD,
TRUNC (DLOGDET.DEPLOYDATE) AS PROD_DEPLOY_DATE,
DLOGDET.DEPLOYREQUEST AS BAAR_RFD,
DLOG.FILENAMEEXT_VC AS SCRIPT_NAME,
DLOG.VERSION,
DLOG.REQUEST,
DLOG.NOTE AS COMMENTS
FROM ADM_DEPLOYMENTLOGDETAIL DLOGDET
JOIN ADM_DEPLOYMENTLOG DLOG ON DLOG.LOGNO = DLOGDET.LOGNO";
using (OracleConnection conn = new OracleConnection(Globals.Constants.AppConnectionStringReadOnly))
{
using (OracleCommand objCommand = new OracleCommand(srtQry, conn))
{
objCommand.CommandType = CommandType.Text;
DataTable dt = new DataTable();
OracleDataAdapter adp = new OracleDataAdapter(objCommand);
conn.Open();
adp.Fill(dt);
if (dt != null)
{
list = ConvertToStamfordProdRelease(dt).ToList();
}
}
}
return list;
}
Oracle 8i did not support standard ANSI SQL JOIN syntax.
That feature was introduced in Oracle 9i Release 2 (aka Oracle 9.2)
Quote from the chapter "What's New in SQL Reference"
SELECT [...] has new ANSI-compliant join syntax.
Don't combine the, strings put all in one.
I can use GetSchemaTable and GetXMLSchema to get information about field types, sizes etc. from a Foxpro DBF opened with VFPOLEDB but can not get any information pertaining to what indexes are in the tables/CDX.
I dont want to use the indexes, just the criteria on which the index is built to aid me in generating the SQL commands to create the tables on a SQL server and import the data.
I could do a DISPLAY STRUCTURE output to a text file on all of the tables and parse it in VB.NET but I am hoping there is something I am overlooking as I am not that familiar with VB.NET/OLEDB syntax yet.
Little bit of research given away these results. I have started with having a look at ForeignKey.FKTableSchema Property and unfortunately not a .NET property. Later on things looked good when I found OleDbSchemaGuid.Indexes Field and everything looked good until I ran the application and got the Method is not supported by this provider. Eventually the following article lit up the way,
GetOleDbSchemaTable(OleDb.OleDbSchemaGuid.Indexes - How to access included columns on index
and this finding
The OleDb and Odbc providers do not provide a built-in catalog method
that will return non-key ("Included") index columns.
However it was some really interesting suggestion which let to writing this little Console application for you to harvest the indexes available in the table. This is achieved by directly querying the schema table from SQL. The following example is on Employees table of famous Northwind sample database. Here you go,
//Open a connection to the SQL Server Northwind database.
var connectionString =
"Provider=SQLOLEDB;Data Source=SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=SSPI;Encrypt=False;TrustServerCertificate=False";
using (var connection = new OleDbConnection(connectionString))
{
connection.Open();
var select = "SELECT " +
" T.name AS TABLE_NAME" +
" , IX.name AS INDEX_NAME" +
" , IC.index_column_id AS IX_COL_ID" +
" , C.name AS COLUMN_NAME" +
" , IC.is_included_column AS INCLUDED_NONKEY" +
" " +
"FROM " +
" sys.tables T " +
" INNER JOIN sys.indexes IX" +
" ON T.object_id = IX.object_id " +
" INNER JOIN sys.index_columns IC" +
" ON IX.object_id = IC.object_id " +
" AND IX.index_id = IC.index_id " +
" INNER JOIN sys.columns C" +
" ON IC.object_id = C.object_id " +
" AND IC.column_id = C.column_id " +
" " +
"WHERE T.name = 'Employees'" +
"ORDER BY IC.index_column_id";
OleDbCommand cmd = new OleDbCommand(#select, connection);
cmd.CommandType = CommandType.Text;
var outputTable = new DataSet("Table");
var my = new OleDbDataAdapter(cmd).Fill(outputTable);
foreach (DataTable table in outputTable.Tables)
{
foreach (DataRow myField in table.Rows)
{
//For each property of the field...
foreach (DataColumn myProperty in table.Columns)
{
//Display the field name and value.
Console.WriteLine(myProperty.ColumnName + " = " +
myField[myProperty].ToString());
}
Console.WriteLine();
}
}
}
Console.ReadLine();
and finally the results,
TABLE_NAME = Employees
INDEX_NAME = PK_Employees
IX_COL_ID = 1
COLUMN_NAME = EmployeeID
INCLUDED_NONKEY = False
TABLE_NAME = Employees
INDEX_NAME = LastName
IX_COL_ID = 1
COLUMN_NAME = LastName
INCLUDED_NONKEY = False
TABLE_NAME = Employees
INDEX_NAME = PostalCode
IX_COL_ID = 1
COLUMN_NAME = PostalCode
INCLUDED_NONKEY = False
However, later on by removing the restrictions I managed to get over the Method is not supported by this provider. error and ended up summing it up like this shorter solution,
//Open a connection to the SQL Server Northwind database.
var connectionString =
"Provider=SQLOLEDB;Data Source=SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=SSPI;Encrypt=False;TrustServerCertificate=False";
using (OleDbConnection cnn = new OleDbConnection(connectionString))
{
cnn.Open();
DataTable schemaIndexess = cnn.GetSchema("Indexes",
new string[] {null, null, null});
DataTable schemaIndexes = cnn.GetOleDbSchemaTable(
OleDbSchemaGuid.Indexes,
new object[] {null, null, null});
foreach (DataRow myField in schemaIndexes.Rows)
{
//For each property of the field...
foreach (DataColumn myProperty in schemaIndexes.Columns)
{
//Display the field name and value.
Console.WriteLine(myProperty.ColumnName + " = " +
myField[myProperty].ToString());
}
Console.WriteLine();
}
Console.ReadLine();
}
Which results to a longer output to sort out but part of it would be
TABLE_CATALOG = Northwind
TABLE_SCHEMA = dbo
TABLE_NAME = Employees
INDEX_CATALOG = Northwind
INDEX_SCHEMA = dbo
INDEX_NAME = LastName
PRIMARY_KEY = False
UNIQUE = False
CLUSTERED = False
TYPE = 1
FILL_FACTOR = 0
INITIAL_SIZE =
NULLS =
SORT_BOOKMARKS = False
AUTO_UPDATE = True
NULL_COLLATION = 4
ORDINAL_POSITION = 1
COLUMN_NAME = LastName
COLUMN_GUID =
COLUMN_PROPID =
COLLATION = 1
CARDINALITY =
PAGES = 1
FILTER_CONDITION =
INTEGRATED = False
Perfect!
Everything I needed to extract. Since it was in vb.net section I posted my rough code, I filtered the fields returned so I could list a few here.
It returns all pertinent information relating to the indexes, even complex ones created with expressions.
All tables in the path provided in the Connection String with CDX indexes will be returned.
TABLE_NAME = schematest
INDEX_NAME = char3ascen
NULLS = 1
EXPRESSION = char3ascen
TABLE_NAME = schematest
INDEX_NAME = expressn
NULLS = 2
EXPRESSION = LEFT(char1null,4)+SUBSTR(char2,4,2)
TABLE_NAME = schematest
INDEX_NAME = multifld
NULLS = 2
EXPRESSION = char1null+char2
TABLE_NAME = customer
INDEX_NAME = zip
NULLS = 1
EXPRESSION = zip
Private Sub GetIndexInfo_Click(sender As Object, e As EventArgs) Handles GetIndexInfo.Click
Dim cnnOLEDB As New OleDbConnection
Dim SchemaTable As DataTable
Dim myField As DataRow
Dim myProperty As DataColumn
Dim ColumnNames As New List(Of String)
Dim strConnectionString = "Provider=vfpoledb;Data Source=D:\ACW\;Collating Sequence=general;DELETED=False"
cnnOLEDB.ConnectionString = strConnectionString
cnnOLEDB.Open()
ColumnNames.Add("TABLE_NAME")
columnnames.Add("INDEX_NAME")
columnnames.Add("NULLS")
columnnames.Add("TYPE")
columnnames.Add("EXPRESSION")
SchemaTable = cnnOLEDB.GetSchema("Indexes")
'For Each myProperty In SchemaTable.Columns
For Each myField In SchemaTable.Rows
For Each myProperty In SchemaTable.Columns
If ColumnNames.Contains(myProperty.ColumnName) Then
Console.WriteLine(myProperty.ColumnName & " = " & myField(myProperty).ToString)
End If
Next
Console.WriteLine()
Next
Console.ReadLine()
DGVSchema.DataSource = SchemaTable
End Sub