From 465a4467adec94bb8fe996732ea378664fcf5e86 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 23 Jan 2015 11:40:58 +0200
Subject: Handle SQL name limits in MySQL and SQL Server

---
 NEWS                             | 21 +++++++++++++--------
 odb/relational/mssql/context.cxx | 12 ++++++++++++
 odb/relational/mysql/context.cxx | 14 +++++++++++++-
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/NEWS b/NEWS
index 49e4aa4..ccbedde 100644
--- a/NEWS
+++ b/NEWS
@@ -36,16 +36,21 @@ Version 2.4.0
  * Support for calling MySQL stored procedures. For details and limitations
    refer to Section 17.7, "MySQL Stored Procedures" in the ODB manual.
 
- * New option, --statement-regex, can be used to process prepared statement
-   names that are used by PostgreSQL. This can be useful, for example, to
-   shorten names that exceed the PostgreSQL name limit. To this effect, ODB
-   now also warns when an SQL name exceeds the default PostgreSQL limit of
-   63 characters.
-
  * New option, --oracle-warn-truncation, makes ODB warn about SQL names
    that are longer than 30 characters and are therefore truncated. ODB
-   now also detects when such truncations lead to name conflicts and
-   issues diagnostics even without this option specified.
+   now also detects when such truncations lead to Oracle name conflicts
+   and issues diagnostics even without this option specified.
+
+ * For MySQL, PostgreSQL, and SQL Server, ODB now warns when an SQL name
+   exceeds the database limit (64, 63, and 128 characters, respectively).
+   SQLite has no limitation on name lengths. For Oracle, which has a limit
+   that is much more likely to be reached in normal circumstances (30
+   characters), a more comprehensive detection is implemented (see item
+   above).
+
+ * New option, --statement-regex, can be used to process prepared statement
+   names that are used by PostgreSQL. This can be useful, for example, to
+   shorten names that exceed the PostgreSQL name limit.
 
 Version 2.3.0
 
diff --git a/odb/relational/mssql/context.cxx b/odb/relational/mssql/context.cxx
index e99cdaf..eac4a95 100644
--- a/odb/relational/mssql/context.cxx
+++ b/odb/relational/mssql/context.cxx
@@ -133,6 +133,18 @@ namespace relational
         if (i->empty ())
           continue;
 
+        // Warn if the name is greater than the 128 limit.
+        //
+        if (i->size () > 128)
+        {
+          cerr << "warning: SQL name '" << *i << "' is longer than the "
+               << "SQL Server name limit of 128 characters and will be "
+               << "truncated" << endl;
+
+          cerr << "info: consider shortening it using #pragma db "
+               << "table/column/index or --*-regex options" << endl;
+        }
+
         if (f)
           f = false;
         else
diff --git a/odb/relational/mysql/context.cxx b/odb/relational/mysql/context.cxx
index 4ccb206..945a3a9 100644
--- a/odb/relational/mysql/context.cxx
+++ b/odb/relational/mysql/context.cxx
@@ -129,13 +129,25 @@ namespace relational
         if (i->empty ())
           continue;
 
+        // Warn if the name is greater than the 64 limit.
+        //
+        if (i->size () > 64)
+        {
+          cerr << "warning: SQL name '" << *i << "' is longer than "
+               << "the MySQL name limit of 64 characters and will "
+               << "be truncated" << endl;
+
+          cerr << "info: consider shortening it using #pragma db "
+               << "table/column/index or --*-regex options" << endl;
+        }
+
         if (f)
           f = false;
         else
           r += '.';
 
         r += '`';
-        r += *i;
+        r.append (*i, 0, 64); // Max identifier length is 64.
         r += '`';
       }
 
-- 
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