How to use the tables.StringCol function in tables

self.h5store.file.remove_node(self.where, self.routes_flows)
            except tables.NoSuchNodeError:
                pass
            finally:
                self._routes_flow_array = self.h5store.file.create_carray(self.where, self.routes_flows, atom, shape, createparents=True)

            # Create routes table. This must be done in reset
            if self.routes is not None:
                group_name, node_name = self.routes.rsplit('/', 1)
                if group_name == "":
                    group_name = "/"

                description = {
                    # TODO make string length configurable
                    'start': tables.StringCol(1024),
                    'end': tables.StringCol(1024),
                }
                try:
                    self.h5store.file.remove_node(group_name, node_name)
                except tables.NoSuchNodeError:
                    pass
                finally:
                    tbl = self.h5store.file.create_table(group_name, node_name, description=description, createparents=True)

                entry = tbl.row
                for route in self.model.solver.routes:
                    node_first = route[0]
                    node_last = route[-1]

                    if node_first.parent is not None:
                        node_first = node_first.parent
                    if node_last.parent is not None:

#      WATER QUALITY CONFIGURATION
#

class ReactionTable(IsDescription):
    net_label = StringCol(64)
    reaction_type = EnumCol(reaction_type, 'BULK', base='uint8')
    value = Float32Col()
    
class SourcesTable(IsDescription):
    node_label = StringCol(64)
    source_type = EnumCol(source_type, 'CONCEN', base='uint8')
    strength = Float32Col()
    source_pattern = StringCol(72)

class MixingTable(IsDescription):
    tank_label = StringCol(64)
    mixing_model = EnumCol(mixing_model, 'MIXED', base='uint8')
    mixing_volume = Float32Col()

class InitialQualityTable(IsDescription):
    node_label = StringCol(64)
    node_quality = Float32Col()



class WNMTablesFile(object):
    
    def __init__(self, filename):
        self._filename = filename
        self._network = None
        self.num_links = 0
        self.num_nodes = 0

def add_meta(simulation, key):
            """Create a node for the simulation and add data to /Metadata"""
            
         
            
            class Meta(tbl.IsDescription):
                SID = tbl.StringCol(itemsize=16)
                path = tbl.StringCol(itemsize=160)
                log_analysed = tbl.BoolCol()
                successful = tbl.BoolCol()
                algorithm = tbl.StringCol(itemsize=16)
                cpu_time = tbl.Float32Col()
                successful_steps = tbl.Int32Col()
                steps_nok = tbl.Int32Col()
                timed_out = tbl.BoolCol()
                perc_wrong = tbl.Float32Col()
                time_events_model = tbl.Int32Col()
                time_events_U = tbl.Int32Col()
                state_events = tbl.Int32Col()
                step_events = tbl.Int32Col()
                step_size_min = tbl.Float32Col()
                step_size_max = tbl.Float32Col()
                int_order_max = tbl.Int32Col()

symbol_name = tables.StringCol(255)  # symbol name in code
    symbol_elf_name = tables.StringCol(255)  # symbol name in elf filie
    region_type = tables.EnumCol(region_types, BOOKKEEPING, base='uint8')
    substagenum = tables.UInt8Col()
    new = tables.BoolCol()
    defined = tables.BoolCol()
    undefined = tables.BoolCol()
    writable = tables.BoolCol()
    reclassified = tables.BoolCol()
    allowed_symbol = tables.BoolCol()
    do_print = tables.BoolCol()


class SubstageContents(tables.IsDescription):
    substagenum = tables.UInt8Col(pos=1)
    functionname = tables.StringCol(255, pos=2)


class SubstageEntry(tables.IsDescription):
    substagenum = tables.UInt8Col(pos=1)
    functionname = tables.StringCol(255)
    name = tables.StringCol(255)
    stack = tables.StringCol(255)
    comments = tables.StringCol(255)
    substage_type = tables.EnumCol(substage_types,
                                   BOOKKEEPING, base='uint8')


class SubstageWriteIntervals(tables.IsDescription):
    substagenum = tables.UInt8Col()
    minaddr = tables.UInt64Col()
    minaddrlo = tables.UInt32Col()

TARGET   = tables.StringCol(72)
    SOURCEK  = tables.FloatCol()
    SOURCEM  = tables.FloatCol()
    FILTER   = tables.StringCol(72)
    CELL     = tables.FloatCol(shape=(2,6))
    MATRIX   = tables.FloatCol(shape=(2,9))
    LOWTEMP  = tables.IntCol(shape=(1,3))
    ZOOM     = tables.FloatCol(shape=(1,3))
    CENTER   = tables.FloatCol(shape=(1,4))
    DISTANC  = tables.FloatCol(shape=(1,2)) #has to be observed
    TRAILER  = tables.IntCol()
    COMPRES  = tables.StringCol(72)
    LINEAR   = tables.StringCol(72)
    PHD      = tables.FloatCol(shape=(1,2))
    PREAMP   = tables.FloatCol(shape=(1,2)) #has to be observed
    CORRECT  = tables.StringCol(72)
    WARPFIL  = tables.StringCol(72)
    WAVELEN  = tables.FloatCol(shape=(1,4))
    MAXXY    = tables.FloatCol(shape=(1,2))
    AXIS     = tables.IntCol()
    ENDING   = tables.FloatCol(shape=(1,4))
    DETPAR   = tables.FloatCol(shape=(2,6))
    LUT      = tables.StringCol(72)
    DISPLIM  = tables.FloatCol(shape=(1,2))
    PROGRAM  = tables.StringCol(72)
    ROTATE   = tables.IntCol()
    BITMASK  = tables.StringCol(72)
    OCTMASK  = tables.IntCol(shape=(2,8))
    ESDCELL  = tables.FloatCol(shape=(2,6))
    DETTYPE  = tables.StringCol(72)
    NEXP     = tables.IntCol(shape=(1,5))
    CCDPARM  = tables.FloatCol(shape=(1,5))

def get_groups_description():
    groups_description = OrderedDict([
        ('group', tables.UInt8Col()),
        # ('color', tables.UInt8Col()),
        ('name', tables.StringCol(64)),])
    return groups_description

ayjid = tables.StringCol(200)
    doi = tables.StringCol(100)
    pmid = tables.StringCol(100)
    wosid = tables.StringCol(100)
    abstract = tables.StringCol(5000)
    contents = tables.StringCol(100000)
    accession = tables.StringCol(100)
    date = tables.Int32Col()
    citations = tables.StringCol(5000)  # List of citation keys.
    
class Index(tables.IsDescription):
    """
    For storing int : str pairs.
    """
    i = tables.Int32Col()
    mindex = tables.StringCol(1000)

class IntIndex(tables.IsDescription):    
    """
    For storing int : int pairs.
    """
    i = tables.Int32Col()
    mindex = tables.Int32Col()

class StrIndex(tables.IsDescription):
    """
    For storing str : str pairs.
    """
    i = tables.StringCol(100)
    mindex = tables.StringCol(100000)

class HDF5Axes(dict):

class time (tables.IsDescription):
        '''   Time, either epoch or human readable   '''
        type_s = tables.StringCol(
            8)               # 'EPOCH', 'ASCII', or 'BOTH'
        epoch_l = tables.Int64Col()        # Seconds since January 1, 1970
        ascii_s = tables.StringCol(32)              # WWW MMM DD HH:MM:SS YYYY
        micro_seconds_i = tables.Int32Col()
    #
    event_number_i = tables.Int32Col()  # Event number
    channel_number_i = tables.Int8Col()  # Channel number
    sample_rate_i = tables.Int16Col()  # Trace sample rate
    # This will be needed for sample rates < 1 sps
    sample_rate_multiplier_i = tables.Int16Col()
    sample_count_i = tables.Int32Col()  # Version 2007.191a bleeding
    stream_number_i = tables.Int8Col()  # Stream
    raw_file_name_s = tables.StringCol(32)  # Original file name
    # Name of array that contains trace
    array_name_data_a = tables.StringCol(16)
    array_name_SOH_a = tables.StringCol(16)  # The SOH array name
    array_name_event_a = tables.StringCol(16)  # The event table array
    array_name_log_a = tables.StringCol(16)  # The log array


# Sample rate, int sample interval like SEGY (micro-seconds) or like SEED
# (BLOCKETTE 100)?

class Time (tables.IsDescription):
    '''   Time correction table   '''
    class das (tables.IsDescription):
        manufacturer_s = tables.StringCol(64, pos=3)
        model_s = tables.StringCol(64, pos=2)
        serial_number_s = tables.StringCol(64, pos=1)

import tables as pt #@UnresolvedImport
import time
    
#I DON'T THINK THIS FILE IS NEEDED ANYMORE SHREYAS JOSHI 22 JUN 2010    
    
class StrategyDataModel(pt.IsDescription):
    symbol = pt.StringCol(30)           #30 char string; Ticker
    exchange = pt.StringCol(10)         #10 char string; NYSE, NASDAQ, etc.
    adj_high = pt.Float32Col()
    adj_low = pt.Float32Col()
    adj_open = pt.Float32Col()
    adj_close = pt.Float32Col()
    close = pt.Float32Col()
    volume = pt.Int32Col()
    timestamp = pt.Time64Col()
    date = pt.Int32Col()
    interval = pt.Time64Col()
    
    def __init__(selfparams):
        print "In the constructor"
    #constructor done

def generateDataFile():

# increment step, update_history should handle the rest
        step = self.step+1
        name = self.current[step]['step_name']
        self.update_history('step', name, step)

    class History_Table(tables.IsDescription):
        # Class to describe parameter and protocol change history
        # Columns:
            # Timestamp
            # Type of change - protocol, parameter, step
            # Name - Which parameter was changed, name of protocol, manual vs. graduation step change
            # Value - What was the parameter/protocol/etc. changed to, step if protocol.
        time = tables.StringCol(256)
        type = tables.StringCol(256)
        name = tables.StringCol(256)
        value = tables.StringCol(4028)

    class Weight_Table(tables.IsDescription):
        start = tables.Float32Col()
        stop  = tables.Float32Col()
        date  = tables.StringCol(256)
        session = tables.Int32Col()

    class Hash_Table(tables.IsDescription):
        time = tables.StringCol(256)
        hash = tables.StringCol(40)



############################################################################################
# Utility functions and classes