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NpgsqlDataReader.cs
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1721 lines (1546 loc) · 64.4 KB
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// Npgsql.NpgsqlDataReader.cs
//
// Author:
// Francisco Jr. (fxjrlists@yahoo.com.br)
//
// Copyright (C) 2002 The Npgsql Development Team
// npgsql-general@gborg.postgresql.org
// http://gborg.postgresql.org/project/npgsql/projdisplay.php
//
//
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose, without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph and the following two paragraphs appear in all copies.
//
// IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
// INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
// DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
// THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
// ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Text;
using System.Reflection;
using System.Threading;
using NpgsqlTypes;
namespace Npgsql
{
/// <summary>
/// Provides a means of reading a forward-only stream of rows from a PostgreSQL backend. This class cannot be inherited.
/// </summary>
public abstract class NpgsqlDataReader : DbDataReader
{
//NpgsqlDataReader is abstract because the desired implementation depends upon whether the user
//is using the backwards-compatibility option of preloading the entire reader (configurable from the
//connection string).
//Everything that can be done here is, but where the implementation must be different between the
//two modi operandi, that code will differ between the two implementations, ForwardsOnlyDataReader
//and CachingDataReader.
//Since the concrete classes are internal and returned to the user through an NpgsqlDataReader reference,
//the differences between the two is hidden from the user. Because CachingDataReader is a less efficient
//class supplied only to resolve some backwards-compatibility issues that are possible with some code, all
//internal use uses ForwardsOnlyDataReader directly.
internal NpgsqlConnector _connector;
internal NpgsqlConnection _connection;
internal DataTable _currentResultsetSchema;
internal CommandBehavior _behavior;
internal NpgsqlCommand _command;
internal Version Npgsql205 = new Version("2.0.5");
internal NpgsqlDataReader(NpgsqlCommand command, CommandBehavior behavior)
{
_behavior = behavior;
_connection = (_command = command).Connection;
_connector = command.Connector;
}
internal bool _isClosed = false;
/// <summary>
/// Is raised whenever Close() is called.
/// </summary>
public event EventHandler ReaderClosed;
internal abstract long? LastInsertedOID { get; }
internal bool TryGetTypeInfo(int fieldIndex, out NpgsqlBackendTypeInfo backendTypeInfo)
{
if (CurrentDescription == null)
{
throw new IndexOutOfRangeException(); //Essentially, all indices are out of range.
}
return (backendTypeInfo = CurrentDescription[fieldIndex].TypeInfo) != null;
}
internal abstract void CheckHaveRow();
internal abstract NpgsqlRowDescription CurrentDescription { get; }
/// <summary>
/// Return the data type name of the column at index <param name="Index"></param>.
/// </summary>
public override String GetDataTypeName(Int32 Index)
{
NpgsqlBackendTypeInfo TI;
return TryGetTypeInfo(Index, out TI) ? TI.Name : GetDataTypeOID(Index);
}
/// <summary>
/// Return the data type of the column at index <param name="Index"></param>.
/// </summary>
public override Type GetFieldType(Int32 Index)
{
NpgsqlBackendTypeInfo TI;
return TryGetTypeInfo(Index, out TI) ? TI.FrameworkType : typeof (string); //Default type is string.
}
/// <summary>
/// Return the Npgsql specific data type of the column at requested ordinal.
/// </summary>
/// <param name="ordinal">column position</param>
/// <returns>Appropriate Npgsql type for column.</returns>
public override Type GetProviderSpecificFieldType(int ordinal)
{
NpgsqlBackendTypeInfo TI;
return TryGetTypeInfo(ordinal, out TI) ? TI.Type : typeof(string); //Default type is string.
}
/// <summary>
/// Gets the number of columns in the current row.
/// </summary>
public override Int32 FieldCount
{
get {
if (_connector.CompatVersion <= Npgsql205)
return CurrentDescription == null ? -1 : CurrentDescription.NumFields;
else
// We read msdn documentation and bug report #1010649 that the common return value is 0.
return CurrentDescription == null ? 0 : CurrentDescription.NumFields;
}
}
/// <summary>
/// Return the column name of the column at index <param name="Index"></param>.
/// </summary>
public override String GetName(Int32 Index)
{
if (CurrentDescription == null)
{
throw new IndexOutOfRangeException(); //Essentially, all indices are out of range.
}
return CurrentDescription[Index].Name;
}
/// <summary>
/// Return the data type OID of the column at index <param name="Index"></param>.
/// </summary>
/// FIXME: Why this method returns String?
public String GetDataTypeOID(Int32 Index)
{
if (CurrentDescription == null)
{
throw new IndexOutOfRangeException(); //Essentially, all indices are out of range.
}
return CurrentDescription[Index].TypeOID.ToString();
}
/// <summary>
/// Gets the value of a column in its native format.
/// </summary>
public override Object this[Int32 i]
{
get { return GetValue(i); }
}
public bool HasOrdinal(string fieldName)
{
if(CurrentDescription == null)
throw new InvalidOperationException("Invalid attempt to read when no data is present.");
return CurrentDescription.HasOrdinal(fieldName);
}
/// <summary>
/// Return the column name of the column named <param name="Name"></param>.
/// </summary>
public override Int32 GetOrdinal(String Name)
{
if (CurrentDescription == null)
throw new InvalidOperationException("Invalid attempt to read when no data is present.");
return CurrentDescription.FieldIndex(Name);
}
/// <summary>
/// Gets the value of a column in its native format.
/// </summary>
public override Object this[String name]
{
get
{
return GetValue(GetOrdinal(name));
}
}
/// <summary>
/// Return the data DbType of the column at index <param name="Index"></param>.
/// </summary>
public DbType GetFieldDbType(Int32 Index)
{
NpgsqlBackendTypeInfo TI;
return TryGetTypeInfo(Index, out TI) ? TI.DbType : DbType.String;
}
/// <summary>
/// Return the data NpgsqlDbType of the column at index <param name="Index"></param>.
/// </summary>
public NpgsqlDbType GetFieldNpgsqlDbType(Int32 Index)
{
NpgsqlBackendTypeInfo TI;
return TryGetTypeInfo(Index, out TI) ? TI.NpgsqlDbType : NpgsqlDbType.Text;
}
public BitString GetBitString(int i)
{
object ret = GetValue(i);
if(ret is bool)
return new BitString((bool)ret);
else
return (BitString)ret;
}
/// <summary>
/// Get the value of a column as a <see cref="NpgsqlInterval"/>.
/// <remarks>If the differences between <see cref="NpgsqlInterval"/> and <see cref="System.TimeSpan"/>
/// in handling of days and months is not important to your application, use <see cref="GetTimeSpan(Int32)"/>
/// instead.</remarks>
/// </summary>
/// <param name="i">Index of the field to find.</param>
/// <returns><see cref="NpgsqlInterval"/> value of the field.</returns>
public NpgsqlInterval GetInterval(Int32 i)
{
return (NpgsqlInterval)GetProviderSpecificValue(i);
}
public NpgsqlTime GetTime(int i)
{
return (NpgsqlTime)GetProviderSpecificValue(i);
}
public NpgsqlTimeTZ GetTimeTZ(int i)
{
return (NpgsqlTimeTZ)GetProviderSpecificValue(i);
}
public NpgsqlTimeStamp GetTimeStamp(int i)
{
return (NpgsqlTimeStamp)GetProviderSpecificValue(i);
}
public NpgsqlTimeStampTZ GetTimeStampTZ(int i)
{
return (NpgsqlTimeStampTZ)GetProviderSpecificValue(i);
}
public NpgsqlDate GetDate(int i)
{
return (NpgsqlDate)GetProviderSpecificValue(i);
}
protected void SendClosedEvent()
{
if (this.ReaderClosed != null)
{
this.ReaderClosed(this, EventArgs.Empty);
}
}
/// <summary>
/// Gets the value of a column converted to a Guid.
/// </summary>
public override Guid GetGuid(Int32 i)
{
return (Guid) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Int16.
/// </summary>
public override Int16 GetInt16(Int32 i)
{
return (Int16) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Int32.
/// </summary>
public override Int32 GetInt32(Int32 i)
{
return (Int32) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Int64.
/// </summary>
public override Int64 GetInt64(Int32 i)
{
return (Int64) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Single.
/// </summary>
public override Single GetFloat(Int32 i)
{
return (Single) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Double.
/// </summary>
public override Double GetDouble(Int32 i)
{
return (Double) GetValue(i);
}
/// <summary>
/// Gets the value of a column as String.
/// </summary>
public override String GetString(Int32 i)
{
return (String) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Decimal.
/// </summary>
public override Decimal GetDecimal(Int32 i)
{
return (Decimal) GetValue(i);
}
/// <summary>
/// Gets the value of a column as TimeSpan.
/// </summary>
public TimeSpan GetTimeSpan(Int32 i)
{
return (TimeSpan) GetValue(i);
}
/// <summary>
/// Gets a value indicating the depth of nesting for the current row. Always returns zero.
/// </summary>
public override Int32 Depth
{
get { return 0; }
}
/// <summary>
/// Gets a value indicating whether the data reader is closed.
/// </summary>
public override Boolean IsClosed
{
get { return _isClosed; }
}
/// <summary>
/// Copy values from each column in the current row into <paramref name="values"/>.
/// </summary>
/// <param name="values">Destination for column values.</param>
/// <returns>The number of column values copied.</returns>
public override Int32 GetValues(Object[] values)
{
return LoadValues(values, GetValue);
}
/// <summary>
/// Copy values from each column in the current row into <paramref name="values"></paramref>.
/// </summary>
/// <param name="values">An array appropriately sized to store values from all columns.</param>
/// <returns>The number of column values copied.</returns>
public override int GetProviderSpecificValues(object[] values)
{
return LoadValues(values, GetProviderSpecificValue);
}
private delegate object ValueLoader(int ordinal);
private int LoadValues(object[] values, ValueLoader getValue)
{
CheckHaveRow();
// Only the number of elements in the array are filled.
// It's also possible to pass an array with more that FieldCount elements.
Int32 maxColumnIndex = (values.Length < FieldCount) ? values.Length : FieldCount;
for (Int32 i = 0; i < maxColumnIndex; i++)
{
values[i] = getValue(i);
}
return maxColumnIndex;
}
/// <summary>
/// Gets the value of a column as Boolean.
/// </summary>
public override Boolean GetBoolean(Int32 i)
{
// Should this be done using the GetValue directly and not by converting to String
// and parsing from there?
return (Boolean) GetValue(i);
}
/// <summary>
/// Gets the value of a column as Byte. Not implemented.
/// </summary>
public override Byte GetByte(Int32 i)
{
throw new NotImplementedException();
}
/// <summary>
/// Gets the value of a column as Char.
/// </summary>
public override Char GetChar(Int32 i)
{
//This is an interesting one. In the world of databases we've the idea of chars which is 0 to n characters
//where n is stated (and can perhaps be infinite) and various variations upon that (postgres is admirable
//in being relatively consistent and in not generally encouraging limiting n purely for performance reasons,
//but across many different platforms we'll find such things as text, ntext, char, nchar, varchar, nvarchar,
//and so on with some platforms not having them all and many implementaiton differences).
//
//In the world of .NET, and many other languages, we have the idea of characters and of strings - which are
//sequences of characters with differing degress of encapsulation from C just having char* through to .NET
//having full-blown objects
//
//Database char, varchar, text, etc. are all generally mapped to strings. There's a bit of a question as to
//what maps to a .NET char. Interestingly enough, SQLDataReader doesn't support GetChar() and neither do
//a few other providers (Oracle for example). It would seem that IDataReader.GetChar() was defined largely
//to have a complete set of .NET base types. Still, the closets thing in the database world to a char value
//is a char(1) or varchar(1) - that is to say the value of a string of length one, so that's what is used here.
string s = GetString(i);
if (s.Length != 1)
{
throw new InvalidCastException();
}
return s[0];
}
/// <summary>
/// Gets the value of a column as DateTime.
/// </summary>
public override DateTime GetDateTime(Int32 i)
{
return (DateTime) GetValue(i);
}
/// <summary>
/// Returns a System.Data.DataTable that describes the column metadata of the DataReader.
/// </summary>
public override DataTable GetSchemaTable()
{
return _currentResultsetSchema = _currentResultsetSchema ?? GetResultsetSchema();
}
private DataTable GetResultsetSchema()
{
DataTable result = null;
if (CurrentDescription.NumFields > 0)
{
result = new DataTable("SchemaTable");
result.Columns.Add("ColumnName", typeof (string));
result.Columns.Add("ColumnOrdinal", typeof (int));
result.Columns.Add("ColumnSize", typeof (int));
result.Columns.Add("NumericPrecision", typeof (int));
result.Columns.Add("NumericScale", typeof (int));
result.Columns.Add("IsUnique", typeof (bool));
result.Columns.Add("IsKey", typeof (bool));
result.Columns.Add("BaseCatalogName", typeof (string));
result.Columns.Add("BaseColumnName", typeof (string));
result.Columns.Add("BaseSchemaName", typeof (string));
result.Columns.Add("BaseTableName", typeof (string));
result.Columns.Add("DataType", typeof (Type));
result.Columns.Add("AllowDBNull", typeof (bool));
result.Columns.Add("ProviderType", typeof (string));
result.Columns.Add("IsAliased", typeof (bool));
result.Columns.Add("IsExpression", typeof (bool));
result.Columns.Add("IsIdentity", typeof (bool));
result.Columns.Add("IsAutoIncrement", typeof (bool));
result.Columns.Add("IsRowVersion", typeof (bool));
result.Columns.Add("IsHidden", typeof (bool));
result.Columns.Add("IsLong", typeof (bool));
result.Columns.Add("IsReadOnly", typeof (bool));
if (_connector.BackendProtocolVersion == ProtocolVersion.Version2)
{
FillSchemaTable_v2(result);
}
else if (_connector.BackendProtocolVersion == ProtocolVersion.Version3)
{
FillSchemaTable_v3(result);
}
}
return result;
}
private void FillSchemaTable_v2(DataTable schema)
{
List<string> keyList = (_behavior & CommandBehavior.KeyInfo) == CommandBehavior.KeyInfo
? new List<string>(GetPrimaryKeys(GetTableNameFromQuery()))
: new List<string>();
for (Int16 i = 0; i < CurrentDescription.NumFields; i++)
{
DataRow row = schema.NewRow();
row["ColumnName"] = GetName(i);
row["ColumnOrdinal"] = i + 1;
if (CurrentDescription[i].TypeModifier != -1 && CurrentDescription[i].TypeInfo != null &&
(CurrentDescription[i].TypeInfo.Name == "varchar" || CurrentDescription[i].TypeInfo.Name == "bpchar"))
{
row["ColumnSize"] = CurrentDescription[i].TypeModifier - 4;
}
else if (CurrentDescription[i].TypeModifier != -1 && CurrentDescription[i].TypeInfo != null &&
(CurrentDescription[i].TypeInfo.Name == "bit" || CurrentDescription[i].TypeInfo.Name == "varbit"))
{
row["ColumnSize"] = CurrentDescription[i].TypeModifier;
}
else
{
row["ColumnSize"] = (int) CurrentDescription[i].TypeSize;
}
if (CurrentDescription[i].TypeModifier != -1 && CurrentDescription[i].TypeInfo != null &&
CurrentDescription[i].TypeInfo.Name == "numeric")
{
row["NumericPrecision"] = ((CurrentDescription[i].TypeModifier - 4) >> 16) & ushort.MaxValue;
row["NumericScale"] = (CurrentDescription[i].TypeModifier - 4) & ushort.MaxValue;
}
else
{
row["NumericPrecision"] = 0;
row["NumericScale"] = 0;
}
row["IsUnique"] = false;
row["IsKey"] = IsKey(GetName(i), keyList);
row["BaseCatalogName"] = "";
row["BaseSchemaName"] = "";
row["BaseTableName"] = "";
row["BaseColumnName"] = GetName(i);
row["DataType"] = GetFieldType(i);
row["AllowDBNull"] = true;
// without other information, must allow dbnull on the client
if (CurrentDescription[i].TypeInfo != null)
{
row["ProviderType"] = CurrentDescription[i].TypeInfo.Name;
}
row["IsAliased"] = false;
row["IsExpression"] = false;
row["IsIdentity"] = false;
row["IsAutoIncrement"] = false;
row["IsRowVersion"] = false;
row["IsHidden"] = false;
row["IsLong"] = false;
row["IsReadOnly"] = false;
schema.Rows.Add(row);
}
}
private void FillSchemaTable_v3(DataTable schema)
{
Dictionary<long, Table> oidTableLookup = new Dictionary<long, Table>();
KeyLookup keyLookup = new KeyLookup();
// needs to be null because there is a difference
// between an empty dictionary and not setting it
// the default values will be different
Dictionary<string, Column> columnLookup = null;
if ((_behavior & CommandBehavior.KeyInfo) == CommandBehavior.KeyInfo)
{
List<int> tableOids = new List<int>();
for (int i = 0; i != CurrentDescription.NumFields; ++i)
{
if (CurrentDescription[i].TableOID != 0 && !tableOids.Contains(CurrentDescription[i].TableOID))
{
tableOids.Add(CurrentDescription[i].TableOID);
}
}
oidTableLookup = GetTablesFromOids(tableOids);
if (oidTableLookup.Count == 1)
{
// only 1, but we can't index into the Dictionary
foreach (int key in oidTableLookup.Keys)
{
keyLookup = GetKeys(key);
}
}
columnLookup = GetColumns();
}
for (Int16 i = 0; i < CurrentDescription.NumFields; i++)
{
DataRow row = schema.NewRow();
string baseColumnName = GetBaseColumnName(columnLookup, i);
row["ColumnName"] = GetName(i);
row["ColumnOrdinal"] = i + 1;
if (CurrentDescription[i].TypeModifier != -1 && CurrentDescription[i].TypeInfo != null &&
(CurrentDescription[i].TypeInfo.Name == "varchar" || CurrentDescription[i].TypeInfo.Name == "bpchar"))
{
row["ColumnSize"] = CurrentDescription[i].TypeModifier - 4;
}
else if (CurrentDescription[i].TypeModifier != -1 && CurrentDescription[i].TypeInfo != null &&
(CurrentDescription[i].TypeInfo.Name == "bit" || CurrentDescription[i].TypeInfo.Name == "varbit"))
{
row["ColumnSize"] = CurrentDescription[i].TypeModifier;
}
else
{
row["ColumnSize"] = (int) CurrentDescription[i].TypeSize;
}
if (CurrentDescription[i].TypeModifier != -1 && CurrentDescription[i].TypeInfo != null &&
CurrentDescription[i].TypeInfo.Name == "numeric")
{
row["NumericPrecision"] = ((CurrentDescription[i].TypeModifier - 4) >> 16) & ushort.MaxValue;
row["NumericScale"] = (CurrentDescription[i].TypeModifier - 4) & ushort.MaxValue;
}
else
{
row["NumericPrecision"] = 0;
row["NumericScale"] = 0;
}
row["IsUnique"] = IsUnique(keyLookup, baseColumnName);
row["IsKey"] = IsKey(keyLookup, baseColumnName);
if (CurrentDescription[i].TableOID != 0 && oidTableLookup.ContainsKey(CurrentDescription[i].TableOID))
{
row["BaseCatalogName"] = oidTableLookup[CurrentDescription[i].TableOID].Catalog;
row["BaseSchemaName"] = oidTableLookup[CurrentDescription[i].TableOID].Schema;
row["BaseTableName"] = oidTableLookup[CurrentDescription[i].TableOID].Name;
}
else
{
row["BaseCatalogName"] = row["BaseSchemaName"] = row["BaseTableName"] = "";
}
row["BaseColumnName"] = baseColumnName;
row["DataType"] = GetFieldType(i);
row["AllowDBNull"] = IsNullable(columnLookup, i);
if (CurrentDescription[i].TypeInfo != null)
{
row["ProviderType"] = CurrentDescription[i].TypeInfo.Name;
}
row["IsAliased"] = string.CompareOrdinal((string) row["ColumnName"], baseColumnName) != 0;
row["IsExpression"] = false;
row["IsIdentity"] = false;
row["IsAutoIncrement"] = IsAutoIncrement(columnLookup, i);
row["IsRowVersion"] = false;
row["IsHidden"] = false;
row["IsLong"] = false;
row["IsReadOnly"] = false;
schema.Rows.Add(row);
}
}
private static Boolean IsKey(String ColumnName, IEnumerable<string> ListOfKeys)
{
foreach (String s in ListOfKeys)
{
if (s == ColumnName)
{
return true;
}
}
return false;
}
private IEnumerable<string> GetPrimaryKeys(String tablename)
{
if (string.IsNullOrEmpty(tablename))
{
yield break;
}
String getPKColumns =
"select a.attname from pg_catalog.pg_class ct, pg_catalog.pg_class ci, pg_catalog.pg_attribute a, pg_catalog.pg_index i WHERE ct.oid=i.indrelid AND ci.oid=i.indexrelid AND a.attrelid=ci.oid AND i.indisprimary AND ct.relname = :tablename";
using (NpgsqlConnection metadataConn = _connection.Clone())
{
using (NpgsqlCommand c = new NpgsqlCommand(getPKColumns, metadataConn))
{
c.Parameters.Add(new NpgsqlParameter("tablename", NpgsqlDbType.Text));
c.Parameters["tablename"].Value = tablename;
using (NpgsqlDataReader dr = c.GetReader(CommandBehavior.SingleResult | CommandBehavior.SequentialAccess))
{
while (dr.Read())
{
yield return dr.GetString(0);
}
}
}
}
}
private static bool IsKey(KeyLookup keyLookup, string fieldName)
{
return keyLookup.primaryKey.Contains(fieldName);
}
private static bool IsUnique(KeyLookup keyLookup, string fieldName)
{
return keyLookup.uniqueColumns.Contains(fieldName);
}
private class KeyLookup
{
/// <summary>
/// Contains the column names as the keys
/// </summary>
public readonly List<string> primaryKey = new List<string>();
/// <summary>
/// Contains all unique columns
/// </summary>
public readonly List<string> uniqueColumns = new List<string>();
}
private KeyLookup GetKeys(Int32 tableOid)
{
string getKeys =
"select a.attname, ci.relname, i.indisprimary from pg_catalog.pg_class ct, pg_catalog.pg_class ci, pg_catalog.pg_attribute a, pg_catalog.pg_index i WHERE ct.oid=i.indrelid AND ci.oid=i.indexrelid AND a.attrelid=ci.oid AND i.indisunique AND ct.oid = :tableOid order by ci.relname";
KeyLookup lookup = new KeyLookup();
using (NpgsqlConnection metadataConn = _connection.Clone())
{
NpgsqlCommand c = new NpgsqlCommand(getKeys, metadataConn);
c.Parameters.Add(new NpgsqlParameter("tableOid", NpgsqlDbType.Integer)).Value = tableOid;
using (NpgsqlDataReader dr = c.GetReader(CommandBehavior.SequentialAccess | CommandBehavior.SingleResult))
{
string previousKeyName = null;
string possiblyUniqueColumn = null;
string columnName;
string currentKeyName;
// loop through adding any column that is primary to the primary key list
// add any column that is the only column for that key to the unique list
// unique here doesn't mean general unique constraint (with possibly multiple columns)
// it means all values in this single column must be unique
while (dr.Read())
{
columnName = dr.GetString(0);
currentKeyName = dr.GetString(1);
// if i.indisprimary
if (dr.GetBoolean(2))
{
// add column name as part of the primary key
lookup.primaryKey.Add(columnName);
}
if (currentKeyName != previousKeyName)
{
if (possiblyUniqueColumn != null)
{
lookup.uniqueColumns.Add(possiblyUniqueColumn);
}
possiblyUniqueColumn = columnName;
}
else
{
possiblyUniqueColumn = null;
}
previousKeyName = currentKeyName;
}
// if finished reading and have a possiblyUniqueColumn name that is
// not null, then it is the name of a unique column
if (possiblyUniqueColumn != null)
{
lookup.uniqueColumns.Add(possiblyUniqueColumn);
}
return lookup;
}
}
}
private Boolean IsNullable(Dictionary<string, Column> columnLookup, Int32 FieldIndex)
{
if (columnLookup == null || CurrentDescription[FieldIndex].TableOID == 0)
{
return true;
}
string lookupKey = string.Format("{0},{1}", CurrentDescription[FieldIndex].TableOID, CurrentDescription[FieldIndex].ColumnAttributeNumber);
Column col = null;
return columnLookup.TryGetValue(lookupKey, out col) ? !col.NotNull : true;
}
private string GetBaseColumnName(Dictionary<string, Column> columnLookup, Int32 FieldIndex)
{
if (columnLookup == null || CurrentDescription[FieldIndex].TableOID == 0)
{
return GetName(FieldIndex);
}
string lookupKey = string.Format("{0},{1}", CurrentDescription[FieldIndex].TableOID, CurrentDescription[FieldIndex].ColumnAttributeNumber);
Column col = null;
return columnLookup.TryGetValue(lookupKey, out col) ? col.Name : GetName(FieldIndex);
}
private bool IsAutoIncrement(Dictionary<string, Column> columnLookup, Int32 FieldIndex)
{
if (columnLookup == null || CurrentDescription[FieldIndex].TableOID == 0)
{
return false;
}
string lookupKey = string.Format("{0},{1}", CurrentDescription[FieldIndex].TableOID, CurrentDescription[FieldIndex].ColumnAttributeNumber);
Column col = null;
return
columnLookup.TryGetValue(lookupKey, out col)
? col.ColumnDefault is string && col.ColumnDefault.ToString().StartsWith("nextval(")
: true;
}
///<summary>
/// This methods parses the command text and tries to get the tablename
/// from it.
///</summary>
private String GetTableNameFromQuery()
{
Int32 fromClauseIndex = _command.CommandText.ToLowerInvariant().IndexOf("from");
String tableName = _command.CommandText.Substring(fromClauseIndex + 4).Trim();
if (string.IsNullOrEmpty(tableName))// == String.Empty)
{
return String.Empty;
}
/*if (tableName.EndsWith("."));
return String.Empty;
*/
foreach (Char c in tableName.Substring(0, tableName.Length - 1))
{
if (!Char.IsLetterOrDigit(c) && c != '_' && c != '.')
{
return String.Empty;
}
}
return tableName;
}
private struct Table
{
public readonly string Catalog;
public readonly string Schema;
public readonly string Name;
public readonly int Id;
public Table(IDataReader rdr)
{
Catalog = rdr.GetString(0);
Schema = rdr.GetString(1);
Name = rdr.GetString(2);
Id = rdr.GetInt32(3);
}
}
private Dictionary<long, Table> GetTablesFromOids(List<int> oids)
{
if (oids.Count == 0)
{
return new Dictionary<long, Table>(); //Empty collection is simpler than requiring tests for null;
}
// the column index is used to find data.
// any changes to the order of the columns needs to be reflected in struct Tables
StringBuilder sb =
new StringBuilder(
"SELECT current_database(), nc.nspname, c.relname, c.oid FROM pg_namespace nc, pg_class c WHERE c.relnamespace = nc.oid AND (c.relkind = 'r' OR c.relkind = 'v') AND c.oid IN (");
bool first = true;
foreach (int oid in oids)
{
if (!first)
{
sb.Append(',');
}
sb.Append(oid);
first = false;
}
sb.Append(')');
using (NpgsqlConnection connection = _connection.Clone())
{
using (NpgsqlCommand command = new NpgsqlCommand(sb.ToString(), connection))
{
using (NpgsqlDataReader reader = command.GetReader(CommandBehavior.SequentialAccess | CommandBehavior.SingleResult)
)
{
Dictionary<long, Table> oidLookup = new Dictionary<long, Table>(oids.Count);
int columnCount = reader.FieldCount;
while (reader.Read())
{
Table t = new Table(reader);
oidLookup.Add(t.Id, t);
}
return oidLookup;
}
}
}
}
private class Column
{
public readonly string Name;
public readonly bool NotNull;
public readonly int TableId;
public readonly short ColumnNum;
public readonly object ColumnDefault;
public string Key
{
get { return string.Format("{0},{1}", TableId, ColumnNum); }
}
public Column(IDataReader rdr)
{
Name = rdr.GetString(0);
NotNull = rdr.GetBoolean(1);
TableId = rdr.GetInt32(2);
ColumnNum = rdr.GetInt16(3);
ColumnDefault = rdr.GetValue(4);
}
}
private Dictionary<string, Column> GetColumns()
{
StringBuilder sb = new StringBuilder();
// the column index is used to find data.
// any changes to the order of the columns needs to be reflected in struct Columns
sb.Append(
"SELECT a.attname AS column_name, a.attnotnull AS column_notnull, a.attrelid AS table_id, a.attnum AS column_num, d.adsrc as column_default");
sb.Append(
" FROM pg_attribute a LEFT OUTER JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum WHERE a.attnum > 0 AND (");
bool first = true;
for (int i = 0; i < CurrentDescription.NumFields; ++i)
{
if (CurrentDescription[i].TableOID != 0)
{
if (!first)
{
sb.Append(" OR ");
}
sb.AppendFormat("(a.attrelid={0} AND a.attnum={1})", CurrentDescription[i].TableOID,
CurrentDescription[i].ColumnAttributeNumber);
first = false;
}
}
sb.Append(')');
// if the loop ended without setting first to false, then there will be no results from the query
if (first)
{
return null;
}
using (NpgsqlConnection connection = _connection.Clone())
{
using (NpgsqlCommand command = new NpgsqlCommand(sb.ToString(), connection))
{
using (NpgsqlDataReader reader = command.GetReader(CommandBehavior.SequentialAccess | CommandBehavior.SingleResult)
)
{
Dictionary<string, Column> columnLookup = new Dictionary<string, Column>();
while (reader.Read())
{
Column column = new Column(reader);
columnLookup.Add(column.Key, column);
}
return columnLookup;
}
}
}
}
public override IEnumerator GetEnumerator()
{
return new DbEnumerator(this);
}
}
/// <summary>
/// This is the primary implementation of NpgsqlDataReader. It is the one used in normal cases (where the
/// preload-reader option is not set in the connection string to resolve some potential backwards-compatibility
/// issues), the only implementation used internally, and in cases where CachingDataReader is used, it is still
/// used to do the actual "leg-work" of turning a response stream from the server into a datareader-style
/// object - with CachingDataReader then filling it's cache from here.
/// </summary>
internal class ForwardsOnlyDataReader : NpgsqlDataReader, IStreamOwner
{