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Checking before doing creation table in the database "JAVA"

Posted on 2006-07-12
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Last Modified: 2010-03-31
I want to write a method to create table (CREATE TABLE …) in the database.
I wrote a method doCreation() to generate SQL create statement.
But, I want to check if tableArrayList.get(1) = “name of table” is already in the database or do the creation.
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Question by:javamate06
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LVL 86

Expert Comment

by:CEHJ
ID: 17090347
You could do

CREATE OR REPLACE TABLE

if the Sql of your db allows it. Otherwise you will have to query system tables
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Author Comment

by:javamate06
ID: 17113648
If I use:

CREATE OR REPLACE TABLE

I may face a problem in the size of column, I may create table with minmum size and it will not allowed this.  Becuse of I have for every create statment differenet size of the same column.

If there is a way to check the size and take the maximum.
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Author Comment

by:javamate06
ID: 17113726
Can I have the size of the columns that is already defined in the DB?
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LVL 86

Expert Comment

by:CEHJ
ID: 17113742
>>Can I have the size of the columns that is already defined in the DB?

That would be db-specific. Check for your db. You could build your own mapping between column type and size
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Author Comment

by:javamate06
ID: 17113960
I use:

 java.sql

and I want to retrieve the size of the column from “desc tableName“ query because the second column has the type and the size ,
I tried with this code
 
        ResultSet rs = stmt.executeQuery("desc TABLE2");
            ResultSetMetaData rsmd = rs.getMetaData();
           int numberOfColumns = rsmd.getColumnCount();
          
                while(numberOfColumns !=  0)
                {
                 System.out.println(rsmd.getColumDisplaySize(numberOfColumns));
                 numberOfColumns--;
                 }

It gave me
 
ORA-00900 Invalid SQL statement
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LVL 86

Accepted Solution

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CEHJ earned 80 total points
ID: 17114130
Try

 ResultSet rs = stmt.executeQuery("describe TABLE2");
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Author Comment

by:javamate06
ID: 17114531
For you information use

select count(1) from tab where tname like 'table name';


if count(1) > 0
then table exit;
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LVL 86

Expert Comment

by:CEHJ
ID: 17120368
:-)
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