fixup! Provide a correct MaxAliasLength for various dialects

Author: fredericDelaporte

src/NHibernate/Dialect/Dialect.cs

@@ -2282,10 +2282,11 @@ public virtual string LowercaseFunction
 			get { return "lower"; }
 		}
 
+		// 18 is the smallest of all dialects we handle.
 		/// <summary>
-		/// The maximal length a SQL alias can have.
+		/// The maximum length a SQL alias can have.
 		/// </summary>
-		public virtual int MaxAliasLength => 10;
+		public virtual int MaxAliasLength => 18;
 
 		/// <summary>
 		/// The syntax used to add a column to a table. Note this is deprecated

src/NHibernate/Dialect/IngresDialect.cs

@@ -54,7 +54,11 @@ public IngresDialect()
 		}
 
 		// Ingres 10.2 supports 256 bytes (so worst unicode case would mean 64 characters), but I am unable to find
-		// the limit for older versions, excepted many various sites mention a 32 length limit. Being conservative.
+		// the limit for older versions, excepted many various sites mention a 32 length limit.
+		// https://unifaceinfo.com/docs/0906/Uniface_Library_HTML/ulibrary/INS_NAMING_RULES_8EEFC1A489331BF969D2A8AA36AF2832.html
+		// There are traces of a ticket for increasing this in version 10: http://lists.ingres.com/pipermail/bugs/2010-May/000052.html
+		// This dialect seems to target version below 9, since there is Ingres9Dialect deriving from it.
+		// So sticking to 32.
 		/// <inheritdoc />
 		public override int MaxAliasLength => 32;
 

src/NHibernate/Dialect/MsSql2000Dialect.cs

@@ -677,9 +677,10 @@ public override bool SupportsSqlBatches
 			get { return true; }
 		}
 
-		// SQL Server 2005 supports 128, unable to find the information about SQL Server 2000.
+		// Was 30 in "earlier version", without telling to which version the document apply.
+		// https://msdn.microsoft.com/en-us/library/ms191240.aspx#Anchor_3
 		/// <inheritdoc />
-		public override int MaxAliasLength => 128;
+		public override int MaxAliasLength => 30;
 
 		#region Overridden informational metadata
 

src/NHibernate/Dialect/MsSql2005Dialect.cs

@@ -103,6 +103,10 @@ public override string AppendLockHint(LockMode lockMode, string tableName)
 			return tableName;
 		}
 
+		// SQL Server 2005 supports 128.
+		/// <inheritdoc />
+		public override int MaxAliasLength => 128;
+
 		#region Overridden informational metadata
 
 		/// <summary>

src/NHibernate/Dialect/MySQL5Dialect.cs

@@ -61,5 +61,10 @@ public override bool SupportsInsertSelectIdentity
 		{
 			get { return true; }
 		}
+
+		// At least MySQL 5 is said to support 64 characters for columns, but 5.7 supports 256 for aliases.
+		// 64 seems quite good enough, being conservative.
+		/// <inheritdoc />
+		public override int MaxAliasLength => 64;
 	}
 }

src/NHibernate/Dialect/MySQLDialect.cs

@@ -514,11 +514,6 @@ public override long TimestampResolutionInTicks
 		/// </remarks>
 		public override bool SupportsConcurrentWritingConnectionsInSameTransaction => false;
 
-		// At least MySQL 5 is said to support 64 characters for columns, but 5.7 supports 256 for aliases.
-		// Unable to find the information about previous version, being conservative.
-		/// <inheritdoc />
-		public override int MaxAliasLength => 64;
-
 		#region Overridden informational metadata
 
 		public override bool SupportsEmptyInList => false;

src/NHibernate/Dialect/Oracle12cDialect.cs

@@ -3,7 +3,7 @@
 namespace NHibernate.Dialect
 {
 	/// <summary> 
-	/// A dialect specifically for use with Oracle 12c. Assume 12.2 at least.
+	/// A dialect specifically for use with Oracle 12c.
 	/// </summary>
 	/// <remarks>
 	/// The main difference between this dialect and <see cref="Oracle12cDialect"/>
@@ -39,8 +39,9 @@ public override SqlString GetLimitString(SqlString querySqlString, SqlString off
 			return result.ToSqlString();
 		}
 
-		// 128 since 12.2. https://stackoverflow.com/a/756569/1178314
-		/// <inheritdoc />
-		public override int MaxAliasLength => 128;
+		// 128 since 12.2. https://stackoverflow.com/a/756569/1178314, will
+		// have to do a 12-2c dialect for exploiting it, or wait for 13.
+		// / <inheritdoc />
+		//public override int MaxAliasLength => 128;
 	}
 }

src/NHibernate/Dialect/PostgreSQL81Dialect.cs

@@ -116,5 +116,9 @@ public override bool SupportsInsertSelectIdentity
 
 		/// <inheritdoc />
 		public override bool SupportsDateTimeScale => true;
+
+		// Said to be 63 bytes at least since v8.
+		/// <inheritdoc />
+		public override int MaxAliasLength => 63;
 	}
 }

src/NHibernate/Dialect/PostgreSQLDialect.cs

@@ -291,10 +291,6 @@ public override string CurrentTimestampSelectString
 			get { return "SELECT CURRENT_TIMESTAMP"; }
 		}
 
-		// Said to be 63 bytes at least since v8.
-		/// <inheritdoc />
-		public override int MaxAliasLength => 63;
-
 		#region Overridden informational metadata
 
 		public override bool SupportsEmptyInList => false;

src/NHibernate/Dialect/SQLiteDialect.cs

@@ -397,7 +397,7 @@ public override bool SupportsForeignKeyConstraintInAlterTable
 
 		// Said to be unlimited. http://sqlite.1065341.n5.nabble.com/Max-limits-on-the-following-td37859.html
 		/// <inheritdoc />
-		public override int MaxAliasLength => 100;
+		public override int MaxAliasLength => 128;
 
 		[Serializable]
 		protected class SQLiteCastFunction : CastFunction

src/NHibernate/Dialect/SybaseASA9Dialect.cs

@@ -185,9 +185,5 @@ private static int GetAfterSelectInsertPoint(SqlString sql)
 			}
 			return 0;
 		}
-
-		// Not found documentation for this version, using the lowest from similar products.
-		/// <inheritdoc />
-		public override int MaxAliasLength => 30;
 	}
 }