internal override void CreateTable(String tableName, java.util.Vector <Object> v)
{// throws IOException, tinySQLException {
//---------------------------------------------------
// determin meta data ....
int numCols = v.size();
int recordLength = 1; // 1 byte for the flag field
for (int i = 0; i < numCols; i++)
{
TsColumn coldef = ((TsColumn)v.elementAt(i));
recordLength += coldef.size;
}
//---------------------------------------------------
// create the new dBase file ...
DBFHeader dbfHeader = new DBFHeader(numCols, recordLength);
java.io.RandomAccessFile ftbl = dbfHeader.create(dataDir, tableName);
//---------------------------------------------------
// write out the rest of the columns' definition.
for (int i = 0; i < v.size(); i++)
{
TsColumn coldef = ((TsColumn)v.elementAt(i));
Utils.log("CREATING COL=" + coldef.name);
writeColdef(ftbl, coldef);
}
ftbl.write((byte)0x0d); // header section ends with CR (carriage return)
ftbl.close();
}
/*
* Rename columns
*
* ALTER TABLE table RENAME war TO peace
*/
internal override void AlterTableRenameCol(String tableName, String oldColname, String newColname)
//throws tinySQLException
{
String fullpath = dataDir + java.io.File.separator + tableName + DBFFileTable.dbfExtension;
try
{
java.io.RandomAccessFile ftbl = new java.io.RandomAccessFile(fullpath, "rw");
DBFHeader dbfHeader = new DBFHeader(ftbl); // read the first 32 bytes ...
int locn = 0; // offset of the current column
for (int iCol = 1; iCol <= dbfHeader.numFields; iCol++)
{
TsColumn coldef = readColdef(ftbl, tableName, iCol, locn);
if (coldef.name.equals(oldColname))
{
Utils.log("Replacing column name '" + oldColname + "' with '" + newColname + "'");
ftbl.seek((iCol - 1) * 32 + 32);
ftbl.write(Utils.forceToSize(newColname,
DBFFileTable.FIELD_TYPE_INDEX - DBFFileTable.FIELD_NAME_INDEX,
(byte)0));
ftbl.close();
return;
}
}
ftbl.close();
throw new TinySQLException("Renaming of column name '" + oldColname + "' to '" + newColname + "' failed, no column '" + oldColname + "' found");
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}
/**
* Retrieve a record (=row)
* @param dbfHeader dBase meta info
* @param recordNumber starts with 1
* @return the String with the complete record
* or null if the record is marked as deleted
* @see tinySQLTable#GetCol
*/
public String GetRecord(java.io.RandomAccessFile ff, DBFHeader dbfHeader, int recordNumber) //throws tinySQLException
{
if (recordNumber < 1)
{
throw new TinySQLException("Internal error - current record number < 1");
}
try
{
// seek the starting offset of the current record,
// as indicated by recordNumber
ff.seek(dbfHeader.headerLength + (recordNumber - 1) * dbfHeader.recordLength);
// fully read a byte array out to the length of
// the record.
byte[] b = new byte[dbfHeader.recordLength];
ff.readFully(b);
// make it into a String
String record = new java.lang.StringJ(b, Utils.encode);
// remove deleted records
if (DBFFileTable.isDeleted(record))
{
return(null);
}
return(record);
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}
/*
* Retrieve a column's string value from the given row and given colName
* @param ff the file handle
* @param colName the column name
* @param the wanted record (starts with 1)
* @see tinySQLTable#GetCol
*
* @author Thomas Morgner <*****@*****.**> This function retrieves a
* row, perhaps the name should changed to reflect the new function.
*/
public static String _GetCol(java.io.RandomAccessFile ff, DBFHeader dbfHeader,
int currentRow) //throws TinySQLException
{
try
{
/*
* Seek the starting offset of the current record,
* as indicated by currentRow
*/
ff.seek(dbfHeader.headerLength + (currentRow - 1) * dbfHeader.recordLength);
/*
* Fully read a byte array out to the length of the record and convert
* it into a String.
*/
byte[] b = new byte[dbfHeader.recordLength];
ff.readFully(b);
return(new java.lang.StringJ(b, Utils.encode)); // "Cp437"
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}
/*
* opens a DBF file. This is based on Pratap Pereira's
* Xbase.pm perl module
* @return column definition list (java.util.Hashtable<Object,Object>)
*
* @author Thomas Morgner <*****@*****.**> added check for
* file exists, before the file is opened. Opening a non existing
* file will create a new file, and we get errors while trying
* to read the non-existend headers
*/
java.util.Hashtable <Object, Object> open_dbf() //throws TinySQLException
{
try
{
java.io.File f = new java.io.File(fullPath);
if (TinySQLGlobals.DEBUG)
{
java.lang.SystemJ.outJ.println("Try to open " + f.getAbsolutePath());
}
if (!f.exists())
{
throw new TinySQLException("Unable to open " + f.getAbsolutePath()
+ " - does not exist. or can't be read.");
}
else if (!f.canRead())
{
throw new TinySQLException("Unable to open " + f.getAbsolutePath()
+ " - file can't be read (permissions?).");
}
if (f.canWrite())
{
ftbl = new java.io.RandomAccessFile(f, "rw");
}
else
{
/*
* Open readonly if the file is not writeable. Needed for
* databases on CD-Rom
*/
ftbl = new java.io.RandomAccessFile(f, "r");
}
/*
* Read the first 32 bytes ...
*/
dbfHeader = new DBFHeader(ftbl);
/*
* read the column info (each is a 32 byte bulk) ...
*/
java.util.Hashtable <Object, Object> coldef_list = new java.util.Hashtable <Object, Object>();
columnNameKeys = new java.util.Vector <Object>();
int locn = 0; // offset of the current column
for (int i = 1; i <= dbfHeader.numFields; i++)
{
TsColumn coldef = DBFFile.readColdef(ftbl, table, i, locn);
locn += coldef.size; // increment locn by the length of this field.
coldef_list.put(coldef.name, coldef);
columnNameKeys.addElement(coldef.name);
}
fileOpen = true;
return(coldef_list);
}
catch (Exception e)
{
if (TinySQLGlobals.DEBUG)
{
java.lang.SystemJ.err.println(e.ToString()); // e.printStackTrace();
}
throw new TinySQLException(e.getMessage());
}
}
/*
* Checks whether the row is deleted.
*/
public static bool isDeleted(java.io.RandomAccessFile ff, DBFHeader dbfHeader, int currentRow) //throws TinySQLException
{
char del = _GetCol(ff, dbfHeader, currentRow).charAt(0); // "_DELETED"
return(del == RECORD_IS_DELETED);
}
/**
*
* The DBF File class provides read-only access to DBF
* files, so this baby should throw an exception.
*
* @param fname table name
* @see tinySQL#DropTable
*
*/
internal override void DropTable(String fname)
{//throws tinySQLException {
DBFHeader.dropTable(dataDir, fname);
}
/**
*
* 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());
}
}
