feat: query to fetch unique columns

Signed-off-by: Muhammad Aaqil <[email protected]>

Author: aaqilniz

lib/discovery.js

@@ -335,6 +335,32 @@ function mixinDiscovery(PostgreSQL) {
     return sql;
   };
 
+  /**
+   * Discover unique keys for a given table
+   * @param {String} table The table name
+   * @param {Object} options The options for discovery
+   */
+
+  /*!
+   * Retrieves a list of column names that have unique key index
+   * @param schema
+   * @param table
+   * @returns {string}
+   */
+  PostgreSQL.prototype.buildQueryUniqueKeys = function(schema, table) {
+    const sql = 'SELECT a.attname AS "columnName", n.nspname AS "owner", c.relname AS "tableName" '
+      + 'FROM pg_index i '
+      + 'JOIN pg_class c ON c.oid = i.indrelid '
+      + 'JOIN pg_namespace n ON n.oid = c.relnamespace '
+      + 'JOIN pg_attribute a ON a.attrelid = c.oid AND a.attnum = ANY(i.indkey) '
+      + 'WHERE i.indisunique = true '
+      + 'AND i.indisprimary = false '
+      + 'AND n.nspname = \'' + schema + '\' '
+      + 'AND c.relname = \'' + table + '\' '
+      + 'ORDER BY a.attnum';
+    return sql;
+  };
+
   /**
    * Discover foreign keys that reference to the primary key of this table
    * @param {String} table The table name

package-lock.json

@@ -33,7 +33,7 @@
     "bluebird": "^3.4.6",
     "chalk": "^4.0.0",
     "debug": "^4.1.1",
-    "loopback-connector": "^6.0.0",
+    "loopback-connector": "^6.2.1",
     "pg": "^8.0.2",
     "strong-globalize": "^6.0.0",
     "uuid": "^11.0.0"
@@ -44,7 +44,7 @@
     "eslint": "^8.0.0",
     "eslint-config-loopback": "^13.1.0",
     "lodash": "^4.17.4",
-    "loopback-datasource-juggler": "^5.0.0",
+    "loopback-datasource-juggler": "^5.1.5",
     "mocha": "^11.0.0",
     "rc": "^1.0.0",
     "should": "^13.2.3",

package.json

@@ -394,6 +394,17 @@ describe('Discover LDL schema from a table', function() {
   });
 });
 
+describe('Discover unique properties', function() {
+  it('should validate unique key for user', function(done) {
+    db.discoverSchema('user', {owner: 'strongloop'}, function(err, schema) {
+      console.log('This is our err: ', err);
+      console.log('This is our schema: ', schema);
+      assert(schema.properties.email.index.unique, true);
+      done(null, schema);
+    });
+  });
+});
+
 describe('Discover and map correctly database types', function() {
   it('should handle character varying, date, timestamp with time zone, timestamp without time zone', function(done) {
     db.discoverSchema('customer', {owner: 'strongloop'}, function(err, schema) {

test/postgresql.discover.test.js

@@ -276,6 +276,7 @@ CREATE TABLE "user" (
     email character varying(100)
 );
 
+ALTER TABLE "user" ADD CONSTRAINT user_email_unique UNIQUE (email);
 --
 -- Name: GeoPoint_id_seq; Type: SEQUENCE; Schema: strongloop; Owner: strongloop
 --