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getting ResultSet row count

Posted on 2001-09-06
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Last Modified: 2007-11-27
Does anybody know how to retrieve the number of rows in a ResultSet before you start processing it.  I know that if the ResultSet is scrollable, you can move to the last row, use getRow() and move back.  The problem is that the ResultSet i'm dealing with is type forward only.
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Question by:steeks
11 Comments
 
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Expert Comment

by:pagladasu
ID: 6463143
Assuming that you are using JDBC 2.0, and there is a resulset called 'rs' created in your program. You can try  this:
int nrows=0;
if(rs.last()){
  nrows=rs.getRow();
}

nrows will contain the number of rows.
thanx.
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Accepted Solution

by:
objects earned 50 total points
ID: 6463302
There is no way to find the number of rows in a ResultSet before processing it.
One workaround is to do get the number of rows using a database query. ie. select count(*) from .....
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Expert Comment

by:RBertora
ID: 6464300
One workaround is to do get the number of rows using a database query. ie. select count(*) from .....


.... and pray nothing hits the database to change the count before your result set is returned to you!

aaayeeee!
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Expert Comment

by:kanthonym
ID: 6464614
ResultSet Rs
ResultSetMetaData meta
int rowCount;
if( rs.next() )
{
  rowCount = meta.getColumnCount();
}


Meta Data does not include row count however, you may be interested in more data about the result set....


Method Summary
 String getCatalogName(int column)
          Gets the designated column's table's catalog name.
 String getColumnClassName(int column)
          Returns the fully-qualified name of the Java class whose instances are manufactured if the method ResultSet.getObject is called to retrieve a value from the column.
 int getColumnCount()
          Returns the number of columns in this ResultSet object.
 int getColumnDisplaySize(int column)
          Indicates the designated column's normal maximum width in characters.
 String getColumnLabel(int column)
          Gets the designated column's suggested title for use in printouts and displays.
 String getColumnName(int column)
          Get the designated column's name.
 int getColumnType(int column)
          Retrieves the designated column's SQL type.
 String getColumnTypeName(int column)
          Retrieves the designated column's database-specific type name.
 int getPrecision(int column)
          Get the designated column's number of decimal digits.
 int getScale(int column)
          Gets the designated column's number of digits to right of the decimal point.
 String getSchemaName(int column)
          Get the designated column's table's schema.
 String getTableName(int column)
          Gets the designated column's table name.
 boolean isAutoIncrement(int column)
          Indicates whether the designated column is automatically numbered, thus read-only.
 boolean isCaseSensitive(int column)
          Indicates whether a column's case matters.
 boolean isCurrency(int column)
          Indicates whether the designated column is a cash value.
 boolean isDefinitelyWritable(int column)
          Indicates whether a write on the designated column will definitely succeed.
 int isNullable(int column)
          Indicates the nullability of values in the designated column.
 boolean isReadOnly(int column)
          Indicates whether the designated column is definitely not writable.
 boolean isSearchable(int column)
          Indicates whether the designated column can be used in a where clause.
 boolean isSigned(int column)
          Indicates whether values in the designated column are signed numbers.
 boolean isWritable(int column)
          Indicates whether it is possible for a write on the designated column to succeed.
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Author Comment

by:steeks
ID: 6466408
Would packaging the count query and data query in a transaction ensure the number returned in the count query is the same as the number of rows in the data query?

Would this work, or are transactions only used for insertions/updates/deletes
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Expert Comment

by:dnoelpp
ID: 6516590
I think so. Transaction should be for exact this type of a problem.
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by:Moondancer
ID: 6956284
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Expert Comment

by:knightEknight
ID: 7114473
  Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY );

   ResultSet rst = stmt.executeQuery( strSQL );

   rst.last();
   int numberOfRows = rst.getRow();
   rst.beforeFirst();
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Expert Comment

by:Moondancer
ID: 7118723
Please update and finalize this.
Moondancer - EE Moderator
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by:Venabili
ID: 8908467
No comment has been added lately, so it's time to clean up this TA.
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