Merge pull request #75 from strongloop/refactor-discovery

Refactor SQL discovery methods

lib/sql.js

@@ -1508,3 +1508,300 @@ SQLConnector.prototype.getInsertedId = function(model, info) {
 SQLConnector.prototype.executeSQL = function(sql, params, options, callback) {
   throw new Error(g.f('{{executeSQL()}} must be implemented by the connector'));
 };
+
+// Refactored Discovery methods
+
+/**
+ * Build sql for listing schemas
+ * @param {Object} options Options for discoverDatabaseSchemas
+ */
+SQLConnector.prototype.buildQuerySchemas = function(options) {
+  var sql = 'SELECT catalog_name as "catalog",' +
+   ' schema_name as "schema"' +
+   ' FROM information_schema.schemata';
+  return this.paginateSQL(sql, 'schema_name', options);
+};
+
+/**
+ * Paginate the results returned from database
+ * @param {String} sql The sql to execute
+ * @param {Object} orderBy The property name by which results are ordered
+ * @param {Object} options Options for discoverDatabaseSchemas
+ */
+SQLConnector.prototype.paginateSQL = function(sql, orderBy, options) {
+  throw new Error(g.f('{{paginateSQL}} must be implemented by the connector'));
+};
+/**
+ * Discover database schemas
+ *
+ // * @param {Object} options Options for discovery
+ * @param {Function} [cb] The callback function
+ */
+SQLConnector.prototype.discoverDatabaseSchemas = function(options, cb) {
+  if (!cb && typeof options === 'function') {
+    cb = options;
+    options = {};
+  }
+  options = options || {};
+  var self = this;
+  this.execute(self.buildQuerySchemas(options), cb);
+};
+
+/*!
+ * Build sql for listing tables
+ * @param options {all: for all owners, owner: for a given owner}
+ * @returns {string} The sql statement
+ */
+ // Due to the different implementation structure of information_schema across
+ // connectors, each connector will have to generate its own query
+SQLConnector.prototype.buildQueryTables = function(options) {
+  throw new Error(g.f('{{buildQueryTables}} must be implemented by the connector'));
+};
+
+/*!
+ * Build sql for listing views
+ * @param options {all: for all owners, owner: for a given owner}
+ * @returns {string} The sql statement
+ */
+ // Due to the different implementation structure of information_schema across
+ // connectors, each connector will have to generate its own query
+SQLConnector.prototype.buildQueryViews = function(options) {
+  throw new Error(g.f('{{buildQueryViews}} must be implemented by the connector'));
+};
+
+/**
+ * Discover model definitions
+ *
+ * @param {Object} options Options for discovery
+ * @param {Function} [cb] The callback function
+ */
+SQLConnector.prototype.discoverModelDefinitions = function(options, cb) {
+  if (!cb && typeof options === 'function') {
+    cb = options;
+    options = {};
+  }
+  options = options || {};
+
+  var self = this;
+  var calls = [function(callback) {
+    self.execute(self.buildQueryTables(options), callback);
+  }];
+
+  if (options.views) {
+    calls.push(function(callback) {
+      self.execute(self.buildQueryViews(options), callback);
+    });
+  }
+  async.parallel(calls, function(err, data) {
+    if (err) {
+      cb(err, data);
+    } else {
+      var merged = [];
+      merged = merged.concat(data.shift());
+      if (data.length) {
+        merged = merged.concat(data.shift());
+      }
+      cb(err, merged);
+    }
+  });
+};
+
+/**
+ * Build sql for listing columns
+ * @param {String} schema The schema name
+ * @param {String} table The table name
+ */
+// Due to the different implementation structure of information_schema across
+// connectors, each connector will have to generate its own query
+SQLConnector.prototype.buildQueryColumns = function(schema, table) {
+  throw new Error(g.f('{{buildQueryColumns}} must be implemented by the connector'));
+};
+
+/**
+ * Map the property type from database to loopback
+ * @param {Object} columnDefinition The columnDefinition of the table/schema
+ * @param {Object} options The options for the connector
+ */
+SQLConnector.prototype.buildPropertyType = function(columnDefinition, options) {
+  throw new Error(g.f('{{buildPropertyType}} must be implemented by the connector'));
+};
+
+/*!
+ * Normalize the arguments
+ * @param table string, required
+ * @param options object, optional
+ * @param cb function, optional
+ */
+SQLConnector.prototype.getArgs = function(table, options, cb) {
+  throw new Error(g.f('{{getArgs}} must be implemented by the connector'));
+};
+
+/**
+ * Discover model properties from a table
+ * @param {String} table The table name
+ * @param {Object} options The options for discovery
+ * @param {Function} [cb] The callback function
+ */
+SQLConnector.prototype.discoverModelProperties = function(table, options, cb) {
+  var self = this;
+  var args = self.getArgs(table, options, cb);
+  var schema = args.schema;
+
+  table = args.table;
+  options = args.options;
+
+  if (!schema) {
+    schema = self.getDefaultSchema();
+  }
+
+  self.setDefaultOptions(options);
+  cb = args.cb;
+
+  var sql = self.buildQueryColumns(schema, table);
+  var callback = function(err, results) {
+    if (err) {
+      cb(err, results);
+    } else {
+      results.map(function(r) {
+        r.type = self.buildPropertyType(r, options);
+        self.setNullableProperty(r);
+      });
+      cb(err, results);
+    }
+  };
+  this.execute(sql, callback);
+};
+
+/*!
+ * Build the sql statement for querying primary keys of a given table
+ * @param schema
+ * @param table
+ * @returns {string}
+ */
+// http://docs.oracle.com/javase/6/docs/api/java/sql/DatabaseMetaData.html
+// #getPrimaryKeys(java.lang.String, java.lang.String, java.lang.String)
+// Due to the different implementation structure of information_schema across
+// connectors, each connector will have to generate its own query
+SQLConnector.prototype.buildQueryPrimaryKeys = function(schema, table) {
+  throw new Error(g.f('{{buildQueryPrimaryKeys}} must be implemented by the connector'));
+};
+
+/**
+ * Discover primary keys for a given table
+ * @param {String} table The table name
+ * @param {Object} options The options for discovery
+ * @param {Function} [cb] The callback function
+ */
+SQLConnector.prototype.discoverPrimaryKeys = function(table, options, cb) {
+  var self = this;
+  var args = self.getArgs(table, options, cb);
+  var schema = args.schema;
+
+  if (typeof(self.getDefaultSchema) === 'function' && !schema) {
+    schema = self.getDefaultSchema();
+  }
+  table = args.table;
+  options = args.options;
+  cb = args.cb;
+
+  var sql = self.buildQueryPrimaryKeys(schema, table);
+  this.execute(sql, cb);
+};
+
+/*!
+ * Build the sql statement for querying foreign keys of a given table
+ * @param schema
+ * @param table
+ * @returns {string}
+ */
+ // Due to the different implementation structure of information_schema across
+ // connectors, each connector will have to generate its own query
+SQLConnector.prototype.buildQueryForeignKeys = function(schema, table) {
+  throw new Error(g.f('{{buildQueryForeignKeys}} must be implemented by the connector'));
+};
+
+/**
+ * Discover foreign keys for a given table
+ * @param {String} table The table name
+ * @param {Object} options The options for discovery
+ * @param {Function} [cb] The callback function
+ */
+SQLConnector.prototype.discoverForeignKeys = function(table, options, cb) {
+  var self = this;
+  var args = self.getArgs(table, options, cb);
+  var schema = args.schema;
+
+  if (typeof(self.getDefaultSchema) === 'function' && !schema) {
+    schema = self.getDefaultSchema();
+  }
+  table = args.table;
+  options = args.options;
+  cb = args.cb;
+
+  var sql = self.buildQueryForeignKeys(schema, table);
+  this.execute(sql, cb);
+};
+
+/*!
+ * Retrieves a description of the foreign key columns that reference the
+ * given table's primary key columns (the foreign keys exported by a table).
+ * They are ordered by fkTableOwner, fkTableName, and keySeq.
+ * @param schema
+ * @param table
+ * @returns {string}
+ */
+ // Due to the different implementation structure of information_schema across
+ // connectors, each connector will have to generate its own query
+SQLConnector.prototype.buildQueryExportedForeignKeys = function(schema, table) {
+  throw new Error(g.f('{{buildQueryExportedForeignKeys}} must be implemented by' +
+  'the connector'));
+};
+
+/**
+ * Discover foreign keys that reference to the primary key of this table
+ * @param {String} table The table name
+ * @param {Object} options The options for discovery
+ * @param {Function} [cb] The callback function
+ */
+SQLConnector.prototype.discoverExportedForeignKeys = function(table, options, cb) {
+  var self = this;
+  var args = self.getArgs(table, options, cb);
+  var schema = args.schema;
+
+  if (typeof(self.getDefaultSchema) === 'function' && !schema) {
+    schema = self.getDefaultSchema();
+  }
+  table = args.table;
+  options = args.options;
+  cb = args.cb;
+
+  var sql = self.buildQueryExportedForeignKeys(schema, table);
+  this.execute(sql, cb);
+};
+
+/**
+ * Discover default schema of a database
+ * @param {Object} options The options for discovery
+ */
+SQLConnector.prototype.getDefaultSchema = function(options) {
+  throw new Error(g.f('{{getDefaultSchema}} must be implemented by' +
+  'the connector'));
+};
+
+/**
+ * Set default options for the connector
+ * @param {Object} options The options for discovery
+ */
+SQLConnector.prototype.setDefaultOptions = function(options) {
+  throw new Error(g.f('{{setDefaultOptions}} must be implemented by' +
+  'the connector'));
+};
+
+/**
+ * Set the nullable value for the property
+ * @param {Object} property The property to set nullable
+ */
+SQLConnector.prototype.setNullableProperty = function(property) {
+  throw new Error(g.f('{{setNullableProperty}} must be implemented by' +
+  'the connector'));
+};