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  • Help to chouse NoSQL database for project

    - by potapuff
    There is a table: doc_id(integer)-value(integer) Approximate 100k doc_id and 27?? rows. Majority query on this table - searching documents similar to current document: select 10 documents with maximum of (count common to current document value)/(count ov values in document). Nowadays we use PostgreSQL. Table weight (with index) ~1,5 GB. Average query time ~0.5s. Should I transfer all this to NoSQL base, if so, what?

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  • How to differentiate between two similar fields in Linq Join tables

    - by Azhar
    How to differentiate between two select new fields e.g. Description c.Description and lt.Description DataTable lDt = new DataTable(); try { lDt.Columns.Add(new DataColumn("AreaTypeID", typeof(Int32))); lDt.Columns.Add(new DataColumn("CategoryRef", typeof(Int32))); lDt.Columns.Add(new DataColumn("Description", typeof(String))); lDt.Columns.Add(new DataColumn("CatDescription", typeof(String))); EzEagleDBDataContext lDc = new EzEagleDBDataContext(); var lAreaType = (from lt in lDc.tbl_AreaTypes join c in lDc.tbl_AreaCategories on lt.CategoryRef equals c.CategoryID where lt.AreaTypeID== pTypeId select new { lt.AreaTypeID, lt.Description, lt.CategoryRef, c.Description }).ToArray(); for (int j = 0; j< lAreaType.Count; j++) { DataRow dr = lDt.NewRow(); dr["AreaTypeID"] = lAreaType[j].LandmarkTypeID; dr["CategoryRef"] = lAreaType[j].CategoryRef; dr["Description"] = lAreaType[j].Description; dr["CatDescription"] = lAreaType[j].; lDt.Rows.Add(dr); } } catch (Exception ex) { }

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  • Match entities fulfilling filter (strict superset of search)

    - by Jon
    I have an entity (let's say Person) with a set of arbitrary attributes with a known subset of values. I need to search for all of these entities that match all my filter conditions. That is, given a set of Attributes A, I need to find all people that have a set of Attributes that are a superset of A. For example, my table structures look like this: Person: id | name 1 | John Doe 2 | Jane Roe 3 | John Smith Attribute: id | attr_name 1 | Sex 2 | Eye Color ValidValue: id | attr_id | value_name 1 | 1 | Male 2 | 1 | Female 3 | 2 | Blue 4 | 2 | Green 5 | 2 | Brown PersonAttributes id | person_id | attr_id | value_id 1 | 1 | 1 | 1 2 | 1 | 2 | 3 3 | 2 | 1 | 2 4 | 2 | 2 | 4 5 | 3 | 1 | 1 6 | 3 | 2 | 4 In JPA, I have entities built for all of these tables. What I'd like to do is perform a search for all entities matching a given set of attribute-value pairs. For instance, I'd like to be able to find all males (John Doe and John Smith), all people with green eyes (Jane Roe or John Smith), or all females with green eyes (Jane Roe). I see that I can already take advantage of the fact that I only really need to match on value_id, since that's already unique and tied to the attr_id. But where can I go from there? I've been trying to do something like the following, given that the ValidValue is unique in all cases: select distinct p from Person p join p.personAttributes a where a.value IN (:values) Then I've tried putting my set of required values in as "values", but that gives me errors no matter how I try to structure that. I also have to get a little more complicated, as follows, but at this point I'd be happy with solving the first problem cleanly. However, if it's possible, the Attribute table actually has a field for default value: id | attr_name | default_value 1 | Sex | 1 2 | Eye Color | 5 If the value you're searching on happens to be the default value, I want it to return any people that have no explicit value set for that attribute, because in the application logic, that means they inherit the default value. Again, I'm more concerned about the primary question, but if someone who can help with that also has some idea of how to do this one, I'd be extremely grateful.

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  • custom MSSQL driver

    - by hoodoos
    I had a crazy thought about writing my own MSSQL driver to make it work something like non-blocking http client, so it won't be thread thirsty and could handle lots of db queries within one thread. I tried to look over google for some guidelines about implementing MSSQL client protocol, but found none really, where do those guys get information about it when they write own implementations for PHP or python? I need a really low level to be documented so I can implement all phases of working with a connection through sockets. And would be really nice to have a an example in c# langauge. :)

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  • C# code for viewev tables

    - by simon
    Can somebody write me a code, how to view data from tables in c# (using select statement)? I tried it myself and posted the code here, but i didn't get it right. Please help!

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  • "SELECT TOP", "LEFT OUTER JOIN", "ORDER BY" gives extra rows

    - by Codesleuth
    I have the following Access query I'm running through OLE DB in .NET: SELECT TOP 25 tblClient.ClientCode, tblRegion.Region FROM (tblClient LEFT OUTER JOIN tblRegion ON tblClient.RegionCode = tblRegion.RegionCode) ORDER BY tblRegion.Region There are 431 records within tblClient that have RegionCode set to NULL. For some reason, the query above returns all these 431 records instead of the first 25. If I change the query to ORDER BY tblClient.Client (the name of the client) like so: SELECT TOP 25 tblClient.ClientCode, tblRegion.Region FROM (tblClient LEFT OUTER JOIN tblRegion ON tblClient.RegionCode = tblRegion.RegionCode) ORDER BY tblClient.Client I get the expected result set of 25 records, showing a mixture of region names and NULL values. Why is it that ordering by a field retrieved through a LEFT OUTER JOIN will the TOP clause not work?

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  • Violation of PRIMARY KEY constraint 'PK_

    - by abhi
    hi am trying to write a code in which i need to perform a update but on primary keys how do i achieve it i have written the following code: kindly look at it let me know where m wrong Protected Sub rgKMSLoc_UpdateCommand(ByVal source As Object, ByVal e As Telerik.Web.UI.GridCommandEventArgs) Handles rgKMSLoc.UpdateCommand Try KAYAReqConn.Open() If TypeOf e.Item Is GridEditableItem Then Dim strItemID As String = CType(e.Item.FindControl("hdnID"), HiddenField).Value Dim strrcmbLocation As String = CType(e.Item.FindControl("rcmbLocation"), RadComboBox).SelectedValue Dim strKubeLocation As String = CType(e.Item.FindControl("txtKubeLocation"), TextBox).Text Dim strCSVCode As String = CType(e.Item.FindControl("txtCSVCode"), TextBox).Text SQLCmd = New SqlCommand("SELECT * FROM MstKMSLocKubeLocMapping WHERE LocationID= '" & rcmbLocation.SelectedValue & "'", KAYAReqConn) Dim dr As SqlDataReader dr = SQLCmd.ExecuteReader If dr.HasRows Then lblMsgWarning.Text = "<font color=red>""User ID Already Exists" Exit Sub End If dr.Close() SQLCmd = New SqlCommand("UPDATE MstKMSLocKubeLocMapping SET LocationID=@Location,KubeLocation=@KubeLocation,CSVCode=@CSVCode WHERE LocationID = '" & strItemID & "'", KAYAReqConn) SQLCmd.Parameters.AddWithValue("@Location", Replace(strrcmbLocation, "'", "''")) SQLCmd.Parameters.AddWithValue("@KubeLocation", Replace(strKubeLocation, "'", "''")) SQLCmd.Parameters.AddWithValue("@CSVCode", Replace(strCSVCode, "'", "''")) SQLCmd.Parameters.AddWithValue("@Status", "A") SQLCmd.ExecuteNonQuery() lblMessageUpdate.Text = "<font color=blue>""Record Updated SuccessFully" SQLCmd.Dispose() rgKMSLoc.Rebind() End If Catch ex As Exception Response.Write(ex.ToString) Finally KAYAReqConn.Close() End Try End Sub this is my designer page' Location: ' / ' DataSourceID="dsrcmbLocation" DataTextField="Location" DataValueField="LocationID" Height="150px" Kube Location: ' Class="forTextBox" MaxLength="4" onkeypress="return filterInput(2,event);" CSV Code: ' Class="forTextBox" MaxLength="4" onkeypress="return filterInput(2,event);" <tr class="tableRow"> <td colspan="2" align="center" class="tableCell"> <asp:ImageButton ID="btnUpdate" runat="server" CommandName="Update" CausesValidation="true" ValidationGroup="Update" ImageUrl="~/Images/update.gif"></asp:ImageButton> <asp:ImageButton ID="btnCancel" runat="server" CausesValidation="false" CommandName="Cancel" ImageUrl="~/Images/No.gif"></asp:ImageButton> </td> </tr> </table> </FormTemplate> </EditFormSettings> Locationid is my primary key

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  • error in the syntax of cmd parameters

    - by KATy
    hi guyz in this method i m just adding the values to the db. temp is a object. the field value and variables in the object re havin the same name.. dono y this error s comin plz help me out... public virtual void Save_input_parameter_details(Test_Unit_BLL temp ) { SqlConnection con; con = new SqlConnection("Data Source=VV;Initial Catalog=testingtool;User ID=sa;Password=sa;"); con.Open(); SqlCommand cmd, cmd2, cmd3; //try //{ for (int i = 0; i < temp.No_Input_parameters; i++) { cmd2 = new SqlCommand("insert into Input_parameter_details values(@Input_Parameter_name,@Input_Parameter_datatype,@noparams,@class_code", con); cmd2.Parameters.AddWithValue("@Input_Parameter_datatype", temp.Input_Parameter_datatype[i]); cmd2.Parameters.AddWithValue("@Input_Parameter_name", temp.Input_Parameter_name[i]); cmd2.Parameters.AddWithValue("@noparams", temp.No_Input_parameters); cmd2.Parameters.AddWithValue("@class_code",temp.class_code); cmd2.ExecuteNonQuery(); } //} //catch (Exception ex) // { // MessageBox.Show("error"+ex); // } }

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  • PL/SQL - How to pull data from 3 tables based on latest created date

    - by Nancy
    Hello, I'm hoping someone can help me as I've been stuck on this problem for a few days now. Basically I'm trying to pull data from 3 tables in Oracle: 1) Orders Table 2) Vendor Table and 3) Master Data Table. Here's what the 3 tables look like: Table 1: BIZ_DOC2 (Orders table) OBJECTID (Unique key) UNIQUE_DOC_NAME (Document Name i.e. ORD-005) CREATED_AT (Date the order was created) Table 2: UDEF_VENDOR (Vendors Table): PARENT_OBJECT_ID (This matches up to the ObjectId in the Orders table) VENDOR_OBJECT_NAME (This is the name of the vendor i.e. Acme) Table 3: BIZ_UNIT (Master Data table) PARENT_OBJECT_ID (This matches up to the ObjectID in the Orders table) BIZ_UNIT_OBJECT_NAME (This is the name of the business unit i.e. widget A, widget B) Note: The Vendors Table and Master Data do not have a link between them except through the Orders table. I can join all of the data from the tables and it looks something like this: Before selecting latest order date: ORD-005 | Widget A | Acme | 3/14/10 ORD-005 | Widget B | Acme | 3/14/10 ORD-004 | Widget C | Acme | 3/10/10 Ideally I'd like to return the latest order for each vendor. However, each order may contain multiple business units (e.g. types of widgets) so if a Vendor's latest record is ORD-005 and the order contains 2 business units, here's what the result set should look like by the following columns: UNIQUE_DOC_NAME, BIZ_UNIT_OBJECT_NAME, VENDOR_OBJECT_NAME, CREATED_AT After selecting by latest order date: ORD-005 | Widget A | Acme | 3/14/10 ORD-005 | Widget B | Acme | 3/14/10 I tried using Select Max and several variations of sub-queries but I just can't seem to get it working. Any help would be hugely appreciated!

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  • ALTER TABLE without locking the table?

    - by Daniel
    When doing an ALTER TABLE statement in MySQL, the whole table is read-locked for the duration of the statement. If it's a big table, that means insert or update statements could be locked for a looooong time. Is there a way to do a "hot alter", like adding a column in such a way that the table is still updatable throughout the process? Mostly I'm interested in a solution for MySQL but I'd be interested in other RDBMS if MySQL can't do it. To clarify, my purpose is simply to avoid downtime when a new feature that requires an extra table column is pushed to production. Any database schema will change over time, that's just a fact of life. I don't see why we should accept that these changes must inevitably result in downtime; that's just weak.

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  • How to switch from MSSQL to MySQL for using with Excel pivot

    - by Sim
    Hi all, I have a table that contains sales transaction (~20 mil rows). Previously I used MSSQL and export it to an Excel pivot. Data refresh took 10-15 minutes but still do-able. However, after I migrated to MySQL (using XamppLite & ODBC), it took forever to refresh the data in the Excel pivot. Maybe I didn't optimize the MySQL good enough ? Anyone can share some thoughts 'bout this ? Thanks

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  • SSIS web service task parsing result.

    - by dbengals
    I have an ssis (2005) package that uses the web service task to download to a file destination. The file contains a string of xml data. After downloaded the file looks like this. <?xml version="1.0" encoding="utf-16"?> <string>--here is XML data with escaped characters--</string> My thought was I could then use the XML source data flow source to pull the <string> data, but when I set this up the XML source will not read the <string> as a column. It will generate an xsd and it seems normal, but no luck seeing the column. Any ideas on getting this to work? Or would there be a better way to pull the data within the file generated from the web service? Thanks.

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  • Changing a SUM returned NULL to zero

    - by Lee_McIntosh
    I have a Stored Procedure as follows: CREATE PROC [dbo].[Incidents] (@SiteName varchar(200)) AS SELECT ( SELECT SUM(i.Logged) FROM tbl_Sites s INNER JOIN tbl_Incidents i ON s.Location = i.Location WHERE s.Sites = @SiteName AND i.[month] = DATEADD(mm, DATEDIFF(mm, 0, GetDate()) -1,0) GROUP BY s.Sites ) AS LoggedIncidents 'tbl_Sites contains a list of reported on sites. 'tbl_Incidents containts a generated list of total incidents by site/date (monthly) 'If a site doesnt have any incidents that month it wont be listed. The problem I'm having is that a site doesnt have any Incidents this month and as such i get a NULL value returned for that site when i run this sproc, but i need to have a zero/0 returned to be used within a chart in SSRS. I've tried the using coalesce and isnull to no avail. SELECT COALESCE(SUM(c.Logged,0)) SELECT SUM(ISNULL(c.Logged,0)) Is there a way to get this formatted correctly? Cheers, Lee

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  • T-SQL Table Joins - Unique Situation

    - by Dimitri
    Hello Everyone. This is my first time encountering the case like this and don't quite know how to handle. Situation: I have one table tblSettingsDefinition, with fields: ID, GroupID, Name, typeID, DefaultValue. Then I have tblSettingtypes with fields TypeID, Name. And I have final table, tblUserSettings with fields SettingID, SettingDefinitionID, UserID, Value. The whole point of this is to have customizable settings. Setting can be defined for a Group or as global setting (if GroupID is NULL). It will have a default value, but if user modifies the setting, an entry is added to tblUserSettings that stores new value. I want to have a query that grabs user settings by first looking at the tblUserSettings, and if it has records for the given user, grabs them, if not retrieves default settings. But the trick is that no matter if user has settings or not, I need to have fields from other two table retrieved to know the setting's Type, Name etc... (which are stored in those other tables). I'm writing query something like this: SELECT * FROM tblSettingDefinition SD LEFT JOIN tblUserSettings US ON SD.SettingID = US.SettingDefinitionID JOIN tblSettingTypes ST ON SD.TypeID=ST.ID WHERE US.UserID=@UserID OR ((SD.GroupID IS NULL) OR (SD.GroupID=(SELECT GroupID FROM tblUser WHERE ID=@UserID))) but it retrieves settings for all users from tblUserSettings instead of just ones that match current @UserID. And if @UserID has no records in tblUserSettings, still, all user settings are retrieved instead of the defaults from tblSettingDefinition. Hope I made myself clear. Any help would be highly appreciated. Thank you.

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  • Android : SQL Lite insertion or create table issue

    - by Ram
    Team, can anyone please help me to understand what could be the problem in the below snippet of code? It fails after insertion 2 and insertion 3 debug statements I have the contentValues in the Array list, I am iterating the arraylist and inserting the content values in to the database. Log.d("database","before insertion 1 "); liteDatabase = this.openOrCreateDatabase("Sales", MODE_PRIVATE, null); Log.d("database","before insertion 2 "); liteDatabase .execSQL("Create table activity ( ActivityId VARCHAR,Created VARCHAR,AMTaps_X VARCHAR,AMTemperature_X VARCHAR,AccountId VARCHAR,AccountLocation VARCHAR,AccountName VARCHAR,Classification VARCHAR,ActivityType VARCHAR,COTaps_X VARCHAR,COTemperature_X VARCHAR,Comment VARCHAR,ContactWorkPhone VARCHAR,CreatedByName VARCHAR,DSCycleNo_X VARCHAR,DSRouteNo_X VARCHAR,DSSequenceNo_X VARCHAR,Description VARCHAR,HETaps_X VARCHAR,HETemperature_X VARCHAR,Pro_Setup VARCHAR,LastUpdated VARCHAR,LastUpdatedBy VARCHAR,Licensee VARCHAR,MUTaps_X VARCHAR,MUTemperature_X VARCHAR,Objective VARCHAR,OwnerFirstName VARCHAR,OwnerLastName VARCHAR,PhoneNumber VARCHAR,Planned VARCHAR,PlannedCleanActualDt_X VARCHAR,PlannedCleanReason_X VARCHAR,PrimaryOwnedBy VARCHAR,Pro_Name VARCHAR,ServiceRepTerritory_X VARCHAR,ServiceRep_X VARCHAR,Status VARCHAR,Type VARCHAR,HEINDSTapAuditDate VARCHAR,HEINEmployeeType VARCHAR)"); Log.d("database","before insertion 3 "); int counter = 0; int size = arrayList.size(); for (counter = 0; counter < size; counter++) { ContentValues contentValues = (ContentValues) arrayList .get(counter); liteDatabase.insert("activity", "activityInfo", contentValues); Log.d("database", "Database insertion is done"); } }

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  • Not getting the right expected output for my Mysql Query?

    - by user1878107
    i've 4 tables as shown below doctors id name ------------ 1 Mathew 2 Praveen 3 Rosie 4 Arjun 5 Denis doctors_appointments id doctors_id patient_name contact date status -------------------------------------------------------------------------------------- 1 5 Nidhin 9876543210 2012-12-10 15:39:41 Registered 2 5 Sunny 9876543210 2012-12-18 15:39:48 Registered 3 5 Mani 9876543210 2012-12-12 15:39:57 Registered 4 2 John 9876543210 2012-12-24 15:40:09 Registered 5 4 Raj 9876543210 2012-12-05 15:41:57 Registered 6 3 Samuel 9876543210 2012-12-14 15:41:33 Registered 7 2 Louis 9876543210 2012-12-24 15:40:23 Registered 8 1 Federick 9876543210 2012-12-28 15:41:05 Registered 9 2 Sam 9876543210 2012-12-12 15:40:38 Registered 10 4 Sita 9876543210 2012-12-12 15:41:00 Registered doctors_dutyplan id doctor_id weeks time no_of_patients ------------------------------------------------------------------ 1 1 3,6,7 9:00am-1:00pm 10 2 2 3,4,5 1:00pm-4:00pm 7 3 3 3,6,7 10:00am-2:00pm 10 4 4 3,4,5,6 8:30am-12:30pm 12 5 5 3,4,5,6,7 9:00am-4:00pm 30 emp_leave id empid leavedate -------------------------------- 1 2 2012-12-05 14:42:36 2 2 2012-12-03 14:42:59 3 3 2012-12-03 14:43:06 4 3 2012-12-06 14:43:14 5 5 2012-12-04 14:43:24 My task is to find all the days in a month in which the doctor is available excluding the leave dates. My query what is wrote is given below: SELECT DATE_ADD( '2012-12-01', INTERVAL ROW DAY ) AS Date, ROW +1 AS DayOfMonth FROM ( SELECT @row := @row +1 AS ROW FROM ( SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 )t1, ( SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 )t2, ( SELECT @row := -1 )t3 LIMIT 31 )b WHERE DATE_ADD( '2012-12-01', INTERVAL ROW DAY ) BETWEEN '2012-12-01' AND '2012-12-31' AND DAYOFWEEK( DATE_ADD( '2012-12-01', INTERVAL ROW DAY ) ) =2 AND DATE_ADD( '2012-12-01', INTERVAL ROW DAY ) NOT IN ( SELECT DATE_FORMAT( l.leavedate, '%Y-%m-%d' ) AS date FROM doctors_dutyplan d LEFT JOIN emp_leave AS l ON d.doctor_id = l.empid WHERE doctor_id =2 ) This works fine for all doctors who took any leave in a particular day in a month (here in the example it is Decemeber 2012). and the result is shown below: Date DayOfMonth ----------------------- 2012-12-10 10 2012-12-17 17 2012-12-24 24 2012-12-31 31 But on the other hand for the doctors who did'nt took any leave , for that my query is showing empty table, example for the doctor Mathew whose id is 1, my query returns an empty result can anyone please tell a solution for this problem. Thanks in advance.

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  • Microsoft Sync Framework - Local DB and Remote DB have to have the same schema?

    - by Josh
    When using MSF, is it implied in the technology that the sync tables are supposed to be 1-1? The reason I'm wondering is that if I'm synching from a SQL2005 database to a SQLCE, I might want the CE one to be a little more flattened out so I can get data out with a simpler SELECT statement (as CE does not support sprocs). For example, I might have a tblCustomer, tblOrder, and tblCustomerOrder in the central database, but in the local databases one table with all the data might be preferred. Of course I'd still want the updates to reflect back and forth between the two databases. Does MSF make this possible, or does the local DB have to have the same tables as the central?

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  • value of type 'string' cannot be converted to 'Devart.data.postgresql.PgSqlParameter'

    - by hector
    The following is my PostgreSQL table structure and the vb.net code to insert into the tables.Using Devart's Component For PostgreSQL Connect table gtab83 CREATE TABLE gtab83 ( orderid integer NOT NULL DEFAULT nextval('seq_gtab83_id'::regclass), acid integer, slno integer, orderdte date ) table gtab84 CREATE TABLE gtab84 ( orderdetid integer DEFAULT nextval('seq_gtab84_id'::regclass), productid integer, qty integer, orderid integer ) Code to insert into the above tables is below '1.)INSERT INTO gtab83(orderid,acid, slno, orderdte) VALUES (?, ?, ?); '2.)INSERT INTO gtab84(orderdetid,productid, qty, orderid) VALUES (?, ?, ?); Try Dim cmd As PgSqlCommand = New PgSqlCommand("", Myconnstr) cmd.CommandText = _ "INSERT INTO GTAB83(ACID,SLNO,ORDERDTE)" & _ "VALUES " & _ "(@acid,@slno,@orderdte);" Dim paramAcid As PgSqlParameter = New PgSqlParameter("@acid", PgSqlType.Int, 0) Dim paramSlno As PgSqlParameter = New PgSqlParameter("@slno", PgSqlType.Int, 0) Dim paramOrderdte As PgSqlParameter = New PgSqlParameter("@orderdte", PgSqlType.Date, 0) paramAcid = cboCust.SelectedValue paramSlno = txtOrderNO.Text #ERROR# paramOrderdte = (txtDate.Text, "yyyy-MM-dd") #ERROR# Catch ex As Exception End Try ERROR : value of type 'string' cannot be converted to 'Devart.data.postgresql.PgSqlParameter'

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  • Database Modeling - Either/Or in Many-to-Many

    - by EkoostikMartin
    I have an either/or type of situation in a many-to-many relationship I'm trying to model. So I have these tables: Message ---- *MessageID MessageText Employee ---- *EmployeeID EmployeeName Team ---- *TeamID TeamName MessageTarget ---- MessageID EmployeeID (nullable) TeamID (nullable) So, a Message can have either a list of Employees, or a list of Teams as a MessageTarget. Is the MessageTarget table I have above the best way to implement this relationship? What constraints can I place on the MessageTarget effectively? How should I create a primary key on MessageTarget table?

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  • What are the types and inner workings of a query optimizer?

    - by Frank Developer
    As I understand it, most query optimizers are cost-based. Some can be influenced by hints like FIRST_ROWS(). Others are tailored for OLAP. Is it possible to know more detailed logic about how Informix IDS and SE's optimizers decide what's the best route for processing a query, other than SET EXPLAIN? Is there any documentation which illustrates the ranking of SELECT statements? I would imagine that "SELECT col FROM table WHERE ROWID = n" ranks 1st. What are the rest of them?.. If I'm not mistaking, Informix's ROWID is a SERIAL(INT) which allows for a max. of 2GB nrows, or maybe it uses INT9 for TB's nrows?.. However, I think Oracle uses HEX values for ROWID. Too bad ROWID can't be oftenly used, since a rows ROWID can change. So maybe ROWID is used by the optimizer as a counter? Perhaps, it could be used for implementing the query progress idea I mentioned in my "Begin viewing query results before query completes" question? For some reason, I feel it wouldn't be that difficult to report a query's progress while being processed, perhaps at the expense of some slight overhead, but it would be nice to know ahead of time: A "Google-like" estimate of how many rows meet a query's criteria, display it's progress every 100, 200, 500 or 1,000 rows, give users the ability to cancel it at anytime and start displaying the qualifying rows as they are being put into the current list, while it continues searching?.. This is just one example, perhaps we could think other neat/useful features, the ingridients are more or less there. Perhaps we could fine-tune each query with more granularity than currently available? OLTP queries tend to be mostly static and pre-defined. The "what-if's" are more OLAP, so let's try to add more control and intelligence to it? So, therefore, being able to more precisely control, not "hint-influence" a query is what's needed and therefore it would be necessary to know how the optimizers logic is programmed. We can then have Dynamic SELECT and other statements for specific situations! Maybe even tell IDS to read blocks of indexes nodes at-a-time instead of one-by-one, etc. etc.

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