/**
*
* Deletes Columns from tableName, given a vector of
* column definition (tsColumn) arrays.<br>
*
* ALTER TABLE table DROP [ COLUMN ] column { RESTRICT | CASCADE }
*
* @param tableName the name of the table
* @param v a Vector containing arrays of column definitions.
* @see tinySQL#AlterTableDropCol
*
*/
internal override void AlterTableDropCol(String tableName, java.util.Vector <Object> v)
{//throws IOException, tinySQLException {
// rename the file ...
String fullpath = dataDir + java.io.File.separator + tableName + DBFFileTable.dbfExtension;
String tmppath = dataDir + java.io.File.separator + tableName + "-tmp" + DBFFileTable.dbfExtension;
if (Utils.renameFile(fullpath, tmppath) == false)
{
throw new TinySQLException("ALTER TABLE DROP COL error in renaming " + fullpath);
}
try
{
// open the old file ...
java.io.RandomAccessFile ftbl_tmp = new java.io.RandomAccessFile(tmppath, "r");
// read the first 32 bytes ...
DBFHeader dbfHeader_tmp = new DBFHeader(ftbl_tmp);
// read the column info ...
java.util.Vector <Object> coldef_list = new java.util.Vector <Object>(dbfHeader_tmp.numFields - v.size());
int locn = 0; // offset of the current column
nextCol : for (int i = 1; i <= dbfHeader_tmp.numFields; i++)
{
TsColumn coldef = readColdef(ftbl_tmp, tableName, i, locn);
// remove the DROP columns from the existing cols ...
for (int jj = 0; jj < v.size(); jj++)
{
String colName = (String)v.elementAt(jj);
if (coldef.name.equals(colName))
{
Utils.log("Dropping " + colName);
goto nextCol;
}
}
locn += coldef.size; // increment locn by the length of this field.
// Utils.log("Recycling " + coldef.name);
coldef_list.addElement(coldef);
}
// create the new table ...
CreateTable(tableName, coldef_list);
// copy the data from old to new
// opening new created dBase file ...
java.io.RandomAccessFile ftbl = new java.io.RandomAccessFile(fullpath, "rw");
ftbl.seek(ftbl.length()); // go to end of file
int numRec = 0;
for (int iRec = 1; iRec <= dbfHeader_tmp.numRecords; iRec++)
{
if (DBFFileTable.isDeleted(ftbl_tmp, dbfHeader_tmp, iRec) == true)
{
continue;
}
numRec++;
ftbl.write(DBFFileTable.RECORD_IS_NOT_DELETED); // write flag
// Read the whole column into the table's cache
String column = DBFFileTable._GetCol(ftbl_tmp, dbfHeader_tmp, iRec);
for (int iCol = 0; iCol < coldef_list.size(); iCol++) // write columns
{
TsColumn coldef = (TsColumn)coldef_list.elementAt(iCol);
// Extract column values from cache
String value = DBFFileTable.getColumn(coldef, column);
java.lang.SystemJ.outJ.println("From cache column value" + value);
value = Utils.forceToSize(value, coldef.size, " "); // enforce the correct column length
byte[] b = value.getBytes(Utils.encode); // transform to byte and write to file
ftbl.write(b);
}
}
ftbl_tmp.close();
// remove temp file
java.io.File f = new java.io.File(tmppath);
if (f.exists())
{
f.delete();
}
DBFHeader.writeNumRecords(ftbl, numRec);
ftbl.close();
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}
/**
* Creates new Columns in tableName, given a vector of
* column definition (tsColumn) arrays.<br>
* It is necessary to copy the whole file to do this task.
*
* ALTER TABLE table [ * ] ADD [ COLUMN ] column type
*
* @param tableName the name of the table
* @param v a Vector containing arrays of column definitions.
* @see tinySQL#AlterTableAddCol
*/
internal override void AlterTableAddCol(String tableName, java.util.Vector <Object> v)
{//throws IOException, tinySQLException {
// rename the file ...
String fullpath = dataDir + java.io.File.separator + tableName + DBFFileTable.dbfExtension;
String tmppath = dataDir + java.io.File.separator + tableName + "_tmp_tmp" + DBFFileTable.dbfExtension;
if (Utils.renameFile(fullpath, tmppath) == false)
{
throw new TinySQLException("ALTER TABLE ADD COL error in renaming " + fullpath);
}
try
{
// open the old file ...
java.io.RandomAccessFile ftbl_tmp = new java.io.RandomAccessFile(tmppath, "r");
// read the first 32 bytes ...
DBFHeader dbfHeader_tmp = new DBFHeader(ftbl_tmp);
// read the column info ...
java.util.Vector <Object> coldef_list = new java.util.Vector <Object>(dbfHeader_tmp.numFields + v.size());
int locn = 0; // offset of the current column
for (int i = 1; i <= dbfHeader_tmp.numFields; i++)
{
TsColumn coldef = readColdef(ftbl_tmp, tableName, i, locn);
locn += coldef.size; // increment locn by the length of this field.
coldef_list.addElement(coldef);
}
// add the new column definitions to the existing ...
for (int jj = 0; jj < v.size(); jj++)
{
coldef_list.addElement(v.elementAt(jj));
}
// create the new table ...
CreateTable(tableName, coldef_list);
// copy the data from old to new
// opening new created dBase file ...
java.io.RandomAccessFile ftbl = new java.io.RandomAccessFile(fullpath, "rw");
ftbl.seek(ftbl.length()); // go to end of file
int numRec = 0;
for (int iRec = 1; iRec <= dbfHeader_tmp.numRecords; iRec++)
{
String str = GetRecord(ftbl_tmp, dbfHeader_tmp, iRec);
// Utils.log("Copy of record#" + iRec + " str='" + str + "' ...");
if (str == null)
{
continue; // record was marked as deleted, ignore it
}
ftbl.write(str.getBytes(Utils.encode)); // write original record
numRec++;
for (int iCol = 0; iCol < v.size(); iCol++) // write added columns
{
TsColumn coldef = (TsColumn)v.elementAt(iCol);
// enforce the correct column length
String value = Utils.forceToSize(coldef.defaultVal, coldef.size, " ");
// transform to byte and write to file
byte[] b = value.getBytes(Utils.encode);
ftbl.write(b);
}
}
ftbl_tmp.close();
DBFHeader.writeNumRecords(ftbl, numRec);
ftbl.close();
Utils.delFile(tmppath);
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}