Database policy support for PUT/PATCH operations - PostgreSQL

config-generators/postgresql-commands.txt

@@ -58,8 +58,9 @@ update Publisher --config "dab-config.PostgreSql.json" --permissions "database_p
 update Publisher --config "dab-config.PostgreSql.json" --permissions "database_policy_tester:create"
 update Publisher --config "dab-config.PostgreSql.json" --permissions "database_policy_tester:update" --policy-database "@item.id ne 1234"
 update Stock --config "dab-config.PostgreSql.json" --permissions "authenticated:create,read,update,delete" --rest commodities --graphql true --relationship stocks_price --target.entity stocks_price --cardinality one
-update Stock --config "dab-config.PostgreSql.json" --permissions "database_policy_tester:create,read"
 update Stock --config "dab-config.PostgreSql.json" --permissions "database_policy_tester:update" --policy-database "@item.pieceid ne 1"
+update Stock --config "dab-config.PostgreSql.json" --permissions "database_policy_tester:create" --policy-database "@item.pieceid ne 6 and @item.piecesAvailable gt 0"
+update Stock --config "dab-config.PostgreSql.json" --permissions "database_policy_tester:read"
 update Stock --config "dab-config.PostgreSql.json" --permissions "test_role_with_noread:create,update,delete"
 update Stock --config "dab-config.PostgreSql.json" --permissions "test_role_with_excluded_fields:create,update,delete"
 update Stock --config "dab-config.PostgreSql.json" --permissions "test_role_with_excluded_fields:read" --fields.exclude "categoryName"

src/Core/Configurations/RuntimeConfigValidator.cs

@@ -47,7 +47,8 @@ public class RuntimeConfigValidator : IConfigValidator
     private static readonly HashSet<DatabaseType> _databaseTypesSupportingCreatePolicy =
     [
         DatabaseType.MSSQL,
-        DatabaseType.DWSQL
+        DatabaseType.DWSQL,
+        DatabaseType.PostgreSQL
     ];
 
     // Error messages for user-delegated authentication configuration.

src/Core/Resolvers/PostgreSqlExecutor.cs

@@ -2,11 +2,13 @@
 // Licensed under the MIT License.
 
 using System.Data.Common;
+using System.Net;
 using Azure.Core;
 using Azure.DataApiBuilder.Config;
 using Azure.DataApiBuilder.Config.ObjectModel;
 using Azure.DataApiBuilder.Core.Configurations;
 using Azure.DataApiBuilder.Core.Models;
+using Azure.DataApiBuilder.Service.Exceptions;
 using Azure.Identity;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
@@ -146,6 +148,87 @@ private static bool ShouldManagedIdentityAccessBeAttempted(NpgsqlConnectionStrin
             return string.IsNullOrEmpty(builder.Password);
         }
 
+        /// <inheritdoc/>
+        public override async Task<DbResultSet> GetMultipleResultSetsIfAnyAsync(
+            DbDataReader dbDataReader, List<string>? args = null)
+        {
+            // RS1: COUNT of rows matching PK (no policy) — used to distinguish
+            // "row doesn't exist" from "row exists but policy blocked".
+            DbResultSet resultSetWithCountOfRowsWithGivenPk = await ExtractResultSetFromDbDataReaderAsync(dbDataReader);
+            DbResultSetRow? resultSetRowWithCountOfRowsWithGivenPk = resultSetWithCountOfRowsWithGivenPk.Rows.FirstOrDefault();
+            int numOfRecordsWithGivenPK;
+            bool isFallbackToUpdate;
+
+            if (resultSetRowWithCountOfRowsWithGivenPk is not null &&
+                resultSetRowWithCountOfRowsWithGivenPk.Columns.TryGetValue(PostgresQueryBuilder.COUNT_ROWS_WITH_GIVEN_PK, out object? rowsWithGivenPK) &&
+                resultSetRowWithCountOfRowsWithGivenPk.Columns.TryGetValue(PostgresQueryBuilder.IS_FALLBACK_TO_UPDATE, out object? fallbackToUpdate))
+            {
+                // PostgreSQL COUNT(*) returns Int64; convert to int.
+                numOfRecordsWithGivenPK = Convert.ToInt32(rowsWithGivenPK!);
+                isFallbackToUpdate = Convert.ToBoolean(fallbackToUpdate!);
+            }
+            else
+            {
+                throw new DataApiBuilderException(
+                    message: $"Neither insert nor update could be performed.",
+                    statusCode: HttpStatusCode.InternalServerError,
+                    subStatusCode: DataApiBuilderException.SubStatusCodes.UnexpectedError);
+            }
+
+            // RS2: UPDATE result, or UPDATE+INSERT CTE result.
+            DbResultSet dbResultSet = await dbDataReader.NextResultAsync()
+                ? await ExtractResultSetFromDbDataReaderAsync(dbDataReader)
+                : throw new DataApiBuilderException(
+                    message: $"Neither insert nor update could be performed.",
+                    statusCode: HttpStatusCode.InternalServerError,
+                    subStatusCode: DataApiBuilderException.SubStatusCodes.UnexpectedError);
+
+            if (numOfRecordsWithGivenPK == 1) // Row existed — we attempted an UPDATE.
+            {
+                if (dbResultSet.Rows.Count == 0)
+                {
+                    // Row exists but UPDATE returned no rows — update policy blocked it.
+                    throw new DataApiBuilderException(
+                        message: DataApiBuilderException.AUTHORIZATION_FAILURE,
+                        statusCode: HttpStatusCode.Forbidden,
+                        subStatusCode: DataApiBuilderException.SubStatusCodes.DatabasePolicyFailure);
+                }
+            }
+            else if (dbResultSet.Rows.Count == 0)
+            {
+                // If true, the row simply didn't exist — return 404 (same as MsSql's null-RS2 path).
+                // If false, the INSERT ran but create policy blocked it — return 403.
+
+                if (isFallbackToUpdate)
+                {
+                    if (args is not null && args.Count > 1)
+                    {
+                        string prettyPrintPk = args[0];
+                        string entityName = args[1];
+
+                        throw new DataApiBuilderException(
+                            message: $"Cannot perform INSERT and could not find {entityName} " +
+                            $"with primary key {prettyPrintPk} to perform UPDATE on.",
+                            statusCode: HttpStatusCode.NotFound,
+                            subStatusCode: DataApiBuilderException.SubStatusCodes.ItemNotFound);
+                    }
+
+                    throw new DataApiBuilderException(
+                        message: $"Neither insert nor update could be performed.",
+                        statusCode: HttpStatusCode.InternalServerError,
+                        subStatusCode: DataApiBuilderException.SubStatusCodes.UnexpectedError);
+                }
+
+                // Row didn't exist but INSERT returned no rows — create policy blocked it.
+                throw new DataApiBuilderException(
+                    message: DataApiBuilderException.AUTHORIZATION_FAILURE,
+                    statusCode: HttpStatusCode.Forbidden,
+                    subStatusCode: DataApiBuilderException.SubStatusCodes.DatabasePolicyFailure);
+            }
+
+            return dbResultSet;
+        }
+
         /// <summary>
         /// Determines if the saved default azure credential's access token is valid and not expired.
         /// </summary>

src/Core/Resolvers/PostgresQueryBuilder.cs

@@ -17,6 +17,8 @@ public class PostgresQueryBuilder : BaseSqlQueryBuilder, IQueryBuilder
         private const string UPSERT_IDENTIFIER_COLUMN_NAME = "___upsert_op___";
         private const string INSERT_UPSERT = "inserted";
         private const string UPDATE_UPSERT = "updated";
+        public const string COUNT_ROWS_WITH_GIVEN_PK = "cnt_rows_to_update";
+        public const string IS_FALLBACK_TO_UPDATE = "is_fallback_to_update";
 
         private static DbCommandBuilder _builder = new NpgsqlCommandBuilder();
 
@@ -67,11 +69,17 @@ public string Build(SqlQueryStructure structure)
         /// <inheritdoc />
         public string Build(SqlInsertStructure structure)
         {
-            string insertQuery = $"INSERT INTO {QuoteIdentifier(structure.DatabaseObject.SchemaName)}.{QuoteIdentifier(structure.DatabaseObject.Name)} ";
+            string tableName = $"{QuoteIdentifier(structure.DatabaseObject.SchemaName)}.{QuoteIdentifier(structure.DatabaseObject.Name)}";
+            string dbPolicyPredicates = JoinPredicateStrings(structure.GetDbPolicyForOperation(EntityActionOperation.Create));
+            string insertQuery = $"INSERT INTO {tableName} ";
+
             if (structure.InsertColumns.Any())
             {
-                insertQuery += $"({Build(structure.InsertColumns)}) " +
-                    $"VALUES ({string.Join(", ", (structure.Values))}) ";
+                string insertColumns = Build(structure.InsertColumns);
+                string insertValues = dbPolicyPredicates.Equals(BASE_PREDICATE)
+                    ? $"({insertColumns}) VALUES ({string.Join(", ", structure.Values)})"
+                    : $"({insertColumns}) SELECT {insertColumns} FROM (SELECT {string.Join(", ", structure.InsertColumns.Zip(structure.Values, (col, val) => $"{val} AS {QuoteIdentifier(col)}"))}) AS T WHERE {dbPolicyPredicates}";
+                insertQuery += insertValues;
             }
             else
             {
@@ -117,25 +125,53 @@ public string Build(SqlUpsertQueryStructure structure)
         {
             // https://stackoverflow.com/questions/42668720/check-if-postgres-query-inserted-or-updated-via-upsert
             // relying on xmax to detect insert vs update breaks for views
-            string updatePredicates = JoinPredicateStrings(Build(structure.Predicates), structure.GetDbPolicyForOperation(EntityActionOperation.Update));
-            string updateQuery = $"UPDATE {QuoteIdentifier(structure.DatabaseObject.SchemaName)}.{QuoteIdentifier(structure.DatabaseObject.Name)} " +
+            string tableName = $"{QuoteIdentifier(structure.DatabaseObject.SchemaName)}.{QuoteIdentifier(structure.DatabaseObject.Name)}";
+            string pkPredicates = Build(structure.Predicates);
+            string isFallbackToUpdateSqlLiteral = structure.IsFallbackToUpdate ? "TRUE" : "FALSE";
+
+            // RS1: COUNT of rows matching PK (no policy) — used to distinguish
+            // "row doesn't exist" from "row exists but policy blocked" in the executor.
+            string countQuery = $"SELECT COUNT(*) AS {COUNT_ROWS_WITH_GIVEN_PK}, " +
+                $"{isFallbackToUpdateSqlLiteral} AS {IS_FALLBACK_TO_UPDATE} " +
+                $"FROM {tableName} WHERE {pkPredicates}";
+
+            string updatePredicates = JoinPredicateStrings(pkPredicates, structure.GetDbPolicyForOperation(EntityActionOperation.Update));
+            string updateQuery = $"UPDATE {tableName} " +
                 $"SET {Build(structure.UpdateOperations, ", ")} " +
                 $"WHERE {updatePredicates} " +
                 $"RETURNING {Build(structure.OutputColumns)}, '{UPDATE_UPSERT}' AS {UPSERT_IDENTIFIER_COLUMN_NAME}";
 
             if (structure.IsFallbackToUpdate)
             {
-                return updateQuery + ";";
+                // RS2: UPDATE only — no INSERT branch for autogen PK or missing required columns.
+                return $"{countQuery}; {updateQuery};";
             }
             else
             {
-                return $"WITH update_cte AS ( {updateQuery} ), insert_cte AS ( " +
-                    $"INSERT INTO {QuoteIdentifier(structure.DatabaseObject.SchemaName)}.{QuoteIdentifier(structure.DatabaseObject.Name)} ({Build(structure.InsertColumns)}) " +
-                    $"SELECT {string.Join(", ", (structure.Values))} " +
-                    $"WHERE NOT EXISTS (SELECT 1 FROM update_cte) " +
+                // INSERT only runs when row doesn't exist (pkPredicates match nothing)
+                // AND the create policy (if any) is satisfied.
+                string insertPredicates = JoinPredicateStrings(
+                    $"NOT EXISTS (SELECT 1 FROM {tableName} WHERE {pkPredicates})",
+                    structure.GetDbPolicyForOperation(EntityActionOperation.Create));
+
+                // Alias each value with its column name so that policy predicates referencing
+                // column names (e.g. "pieceid" != @param) can be resolved in the WHERE clause.
+                // Using SELECT ... FROM (SELECT @p1 AS col1, ...) AS T avoids both the VALUES(NULL)
+                // type inference issue and the unnamed-column resolution issue.
+                string namedValues = string.Join(", ",
+                    structure.InsertColumns.Zip(structure.Values,
+                        (col, val) => $"{val} AS {QuoteIdentifier(col)}"));
+
+                // RS2: CTE that attempts UPDATE first; falls through to INSERT only when row is absent.
+                string cteQuery = $"WITH update_cte AS ( {updateQuery} ), insert_cte AS ( " +
+                    $"INSERT INTO {tableName} ({Build(structure.InsertColumns)}) " +
+                    $"SELECT {Build(structure.InsertColumns)} FROM (SELECT {namedValues}) AS T " +
+                    $"WHERE {insertPredicates} " +
                     $"RETURNING {Build(structure.OutputColumns)}, '{INSERT_UPSERT}' AS {UPSERT_IDENTIFIER_COLUMN_NAME} ) " +
-                    $"SELECT {BuildListOfLabels(structure.OutputColumns)}, {UPSERT_IDENTIFIER_COLUMN_NAME} FROM update_cte UNION " +
+                    $"SELECT {BuildListOfLabels(structure.OutputColumns)}, {UPSERT_IDENTIFIER_COLUMN_NAME} FROM update_cte UNION ALL " +
                     $"SELECT {BuildListOfLabels(structure.OutputColumns)}, {UPSERT_IDENTIFIER_COLUMN_NAME} FROM insert_cte;";
+
+                return $"{countQuery}; {cteQuery}";
             }
         }
 

src/Core/Resolvers/SqlMutationEngine.cs

@@ -715,52 +715,37 @@ await PerformMutationOperation(
                                             parameters: parameters,
                                             sqlMetadataProvider: sqlMetadataProvider);
 
-                                if (mutationResultRow is null || mutationResultRow.Columns.Count == 0)
+                                if (mutationResultRow is null)
+                                {
+                                    HttpStatusCode statusCode = effectiveOperationType is EntityActionOperation.Insert
+                                        ? HttpStatusCode.InternalServerError
+                                        : HttpStatusCode.NotFound;
+
+                                    // Ideally this case should not happen, however may occur due to unexpected reasons,
+                                    // like the DbDataReader being null. We throw an exception
+                                    // which will be returned as an UnexpectedError.
+                                    throw new DataApiBuilderException(
+                                        message: "An unexpected error occurred while trying to execute the query.",
+                                        statusCode: statusCode,
+                                        subStatusCode: DataApiBuilderException.SubStatusCodes.UnexpectedError);
+                                }
+
+                                if (mutationResultRow.Columns.Count == 0)
                                 {
                                     if (effectiveOperationType is EntityActionOperation.Insert)
                                     {
-                                        if (mutationResultRow is null)
-                                        {
-                                            // Ideally this case should not happen, however may occur due to unexpected reasons,
-                                            // like the DbDataReader being null. We throw an exception
-                                            // which will be returned as an UnexpectedError.
-                                            throw new DataApiBuilderException(
-                                                message: "An unexpected error occurred while trying to execute the query.",
-                                                statusCode: HttpStatusCode.InternalServerError,
-                                                subStatusCode: DataApiBuilderException.SubStatusCodes.UnexpectedError);
-                                        }
-
-                                        if (mutationResultRow.Columns.Count == 0)
-                                        {
-                                            throw new DataApiBuilderException(
-                                                message: "Could not insert row with given values.",
-                                                statusCode: HttpStatusCode.Forbidden,
-                                                subStatusCode: DataApiBuilderException.SubStatusCodes.DatabasePolicyFailure
-                                                );
-                                        }
+                                        throw new DataApiBuilderException(
+                                            message: "Could not insert row with given values.",
+                                            statusCode: HttpStatusCode.Forbidden,
+                                            subStatusCode: DataApiBuilderException.SubStatusCodes.DatabasePolicyFailure
+                                            );
                                     }
-                                    else
-                                    {
-                                        if (mutationResultRow is null)
-                                        {
-                                            // Ideally this case should not happen, however may occur due to unexpected reasons,
-                                            // like the DbDataReader being null. We throw an exception
-                                            // which will be returned as an UnexpectedError
-                                            throw new DataApiBuilderException(message: "An unexpected error occurred while trying to execute the query.",
-                                                                                statusCode: HttpStatusCode.NotFound,
-                                                                                subStatusCode: DataApiBuilderException.SubStatusCodes.UnexpectedError);
-                                        }
-
-                                        if (mutationResultRow.Columns.Count == 0)
-                                        {
-                                            // This code block is reached when Update or UpdateIncremental operation does not successfully find the record to
-                                            // update. An exception is thrown which will be returned as a 404 NotFound response.
-                                            throw new DataApiBuilderException(message: "No Update could be performed, record not found",
-                                                                                statusCode: HttpStatusCode.NotFound,
-                                                                                subStatusCode: DataApiBuilderException.SubStatusCodes.EntityNotFound);
-                                        }
 
-                                    }
+                                    // This code block is reached when Update or UpdateIncremental operation does not successfully find the record to
+                                    // update. An exception is thrown which will be returned as a 404 NotFound response.
+                                    throw new DataApiBuilderException(message: "No Update could be performed, record not found",
+                                                                        statusCode: HttpStatusCode.NotFound,
+                                                                        subStatusCode: DataApiBuilderException.SubStatusCodes.EntityNotFound);
                                 }
 
                                 // The role with which the REST request is executed can have database policies defined for the read action.
@@ -2264,7 +2249,7 @@ private void AuthorizeEntityAndFieldsForMutation(
         ///     }
         /// }
         /// </code>
-        /// 
+        ///
         /// Example 2 - Multiple items creation:
         /// <code>
         /// mutation {