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Generic LookupCall [message #1099541]

Sun, 01 September 2013 22:28

Zem Wilbury

Messages: 2
Registered: September 2013

Junior Member

I have a couple of SQL tables. Every one of them has an ID & NAME column. I don't want to write a bunch of LookupServices with exact the same SQL but the table's name. So I have only one:

  protected String getConfiguredSqlSelect() {
    return "SELECT  ID, NAME " +
        "FROM    :tablename " +
        "WHERE   1=1" +
        "<key>   AND ID = :key </key> " +
        "<text>  AND UPPER(NAME) LIKE UPPER(:text'%') </text> " +
        "<all> </all> ";
  }

When the LookupCall's tablename attribute is filled with e.g. "COUNTRY" the SQL has a syntax error: "SELECT ID, NAME FROM 'COUNTRY' WHERE 1=1"

Is there a solution solving my problem? Thx.

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Re: Generic LookupCall [message #1100011 is a reply to message #1099541]

Mon, 02 September 2013 14:27

Jason Fauble

Messages: 10
Registered: June 2011
Location: Tallahassee, Florida

Junior Member

It appears as though the variable replacement automatically inserts single quotes for queries. It's not as elegant but you may want to try something like:

  protected String getConfiguredSqlSelect() {
    return "SELECT  ID, NAME " +
        "FROM " + getTablename() + " " +
        "WHERE   1=1" +
        "<key>   AND ID = :key </key> " +
        "<text>  AND UPPER(NAME) LIKE UPPER(:text'%') </text> " +
        "<all> </all> ";
  }

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Re: Generic LookupCall [message #1100085 is a reply to message #1100011]

Mon, 02 September 2013 16:46

Zem Wilbury

Messages: 2
Registered: September 2013

Junior Member

I guess I doesn't work. Because 'tablename' has to be set in the LookupCall on client side, but getTableName() is a method of the LookupService on server side.

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Re: Generic LookupCall [message #1100137 is a reply to message #1100085]

Mon, 02 September 2013 18:41

Jeremie Bresson

Messages: 1252
Registered: October 2011

Senior Member

Jason Fauble wrote on Mon, 02 September 2013 16:27

It appears as though the variable replacement automatically inserts single quotes for queries.

This is intended.

It belongs to the JDBC best practices: #6: Use Bind variables instead of String concatenation.

In my opinion you cannot use placeholders for table names (there is also nothing to optimize, because of the different tables there will be different statements).

Zem Wilbury wrote on Mon, 02 September 2013 18:46

I guess I doesn't work. Because 'tablename' has to be set in the LookupCall on client side, but getTableName() is a method of the LookupService on server side.

This is true, but are you sure that you want the client to know about the database?
In my opinion, the client has nothing to know about the database. I do not want any business code dealing with table names in the client. Database belongs to the server side logic.

I often have a LookupService for each entity (which might be related to the database tables or not. Sometime due to historical reason multiple entities are stored in the same table with an additional column to distinguish them).

If you want to stick to your pattern (Table name set client-side with a generic LookupCall and LookupService) [*], this is also possible, but you will need to write your own LookupService (extending AbstractLookupService and not AbstractSqlLookupService).

Let me know if you need more explanations.

[*] note: I have not seen your code, I can tell if this is a good idea in your case or not

[Updated on: Mon, 02 September 2013 18:43]

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