Extract `data_source_sql` to refactor data source statements

8 files changed, 155 insertions, 202 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index bdcdfe4982..1ef2c4c860 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -31,6 +31,8 @@ module ActiveRecord
       # Returns the relation names useable to back Active Record models.
       # For most adapters this means all #tables and #views.
       def data_sources
+        select_values(data_source_sql, "SCHEMA")
+      rescue NotImplementedError
         tables | views
       end
 
@@ -39,12 +41,14 @@ module ActiveRecord
       #   data_source_exists?(:ebooks)
       #
       def data_source_exists?(name)
+        select_values(data_source_sql(name), "SCHEMA").any? if name.present?
+      rescue NotImplementedError
         data_sources.include?(name.to_s)
       end
 
       # Returns an array of table names defined in the database.
       def tables
-        raise NotImplementedError, "#tables is not implemented"
+        select_values(data_source_sql(type: "BASE TABLE"), "SCHEMA")
       end
 
       # Checks to see if the table +table_name+ exists on the database.
@@ -52,12 +56,14 @@ module ActiveRecord
       #   table_exists?(:developers)
       #
       def table_exists?(table_name)
+        select_values(data_source_sql(table_name, type: "BASE TABLE"), "SCHEMA").any? if table_name.present?
+      rescue NotImplementedError
         tables.include?(table_name.to_s)
       end
 
       # Returns an array of view names defined in the database.
       def views
-        raise NotImplementedError, "#views is not implemented"
+        select_values(data_source_sql(type: "VIEW"), "SCHEMA")
       end
 
       # Checks to see if the view +view_name+ exists on the database.
@@ -65,6 +71,8 @@ module ActiveRecord
       #   view_exists?(:ebooks)
       #
       def view_exists?(view_name)
+        select_values(data_source_sql(view_name, type: "VIEW"), "SCHEMA").any? if view_name.present?
+      rescue NotImplementedError
         views.include?(view_name.to_s)
       end
 
@@ -1306,6 +1314,14 @@ module ActiveRecord
         def can_remove_index_by_name?(options)
           options.is_a?(Hash) && options.key?(:name) && options.except(:name, :algorithm).empty?
         end
+
+        def data_source_sql(name = nil, type: nil)
+          raise NotImplementedError
+        end
+
+        def quoted_scope(name = nil, type: nil)
+          raise NotImplementedError
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 14269b4570..286c98228c 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -6,6 +6,7 @@ require "active_record/connection_adapters/mysql/quoting"
 require "active_record/connection_adapters/mysql/schema_creation"
 require "active_record/connection_adapters/mysql/schema_definitions"
 require "active_record/connection_adapters/mysql/schema_dumper"
+require "active_record/connection_adapters/mysql/schema_statements"
 require "active_record/connection_adapters/mysql/type_metadata"
 
 require "active_support/core_ext/string/strip"
@@ -15,6 +16,7 @@ module ActiveRecord
     class AbstractMysqlAdapter < AbstractAdapter
       include MySQL::Quoting
       include MySQL::ColumnDumper
+      include MySQL::SchemaStatements
 
       def update_table_definition(table_name, base) # :nodoc:
         MySQL::Table.new(table_name, base)
@@ -314,57 +316,6 @@ module ActiveRecord
         show_variable "collation_database"
       end
 
-      def tables # :nodoc:
-        sql = "SELECT table_name FROM information_schema.tables WHERE table_type = 'BASE TABLE'"
-        sql << " AND table_schema = #{quote(@config[:database])}"
-
-        select_values(sql, "SCHEMA")
-      end
-
-      def views # :nodoc:
-        select_values("SHOW FULL TABLES WHERE table_type = 'VIEW'", "SCHEMA")
-      end
-
-      def data_sources # :nodoc:
-        sql = "SELECT table_name FROM information_schema.tables "
-        sql << "WHERE table_schema = #{quote(@config[:database])}"
-
-        select_values(sql, "SCHEMA")
-      end
-
-      def table_exists?(table_name) # :nodoc:
-        return false unless table_name.present?
-
-        schema, name = extract_schema_qualified_name(table_name)
-
-        sql = "SELECT table_name FROM information_schema.tables WHERE table_type = 'BASE TABLE'"
-        sql << " AND table_schema = #{quote(schema)} AND table_name = #{quote(name)}"
-
-        select_values(sql, "SCHEMA").any?
-      end
-
-      def data_source_exists?(table_name) # :nodoc:
-        return false unless table_name.present?
-
-        schema, name = extract_schema_qualified_name(table_name)
-
-        sql = "SELECT table_name FROM information_schema.tables "
-        sql << "WHERE table_schema = #{quote(schema)} AND table_name = #{quote(name)}"
-
-        select_values(sql, "SCHEMA").any?
-      end
-
-      def view_exists?(view_name) # :nodoc:
-        return false unless view_name.present?
-
-        schema, name = extract_schema_qualified_name(view_name)
-
-        sql = "SELECT table_name FROM information_schema.tables WHERE table_type = 'VIEW'"
-        sql << " AND table_schema = #{quote(schema)} AND table_name = #{quote(name)}"
-
-        select_values(sql, "SCHEMA").any?
-      end
-
       def truncate(table_name, name = nil)
         execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
       end
@@ -410,13 +361,13 @@ module ActiveRecord
       end
 
       def table_comment(table_name) # :nodoc:
-        schema, name = extract_schema_qualified_name(table_name)
+        scope = quoted_scope(table_name)
 
         select_value(<<-SQL.strip_heredoc, "SCHEMA")
           SELECT table_comment
           FROM information_schema.tables
-          WHERE table_schema = #{quote(schema)}
-            AND table_name = #{quote(name)}
+          WHERE table_schema = #{scope[:schema]}
+            AND table_name = #{scope[:name]}
         SQL
       end
 
@@ -516,7 +467,7 @@ module ActiveRecord
       def foreign_keys(table_name)
         raise ArgumentError unless table_name.present?
 
-        schema, name = extract_schema_qualified_name(table_name)
+        scope = quoted_scope(table_name)
 
         fk_info = select_all(<<-SQL.strip_heredoc, "SCHEMA")
           SELECT fk.referenced_table_name AS 'to_table',
@@ -529,9 +480,9 @@ module ActiveRecord
           JOIN information_schema.referential_constraints rc
           USING (constraint_schema, constraint_name)
           WHERE fk.referenced_column_name IS NOT NULL
-            AND fk.table_schema = #{quote(schema)}
-            AND fk.table_name = #{quote(name)}
-            AND rc.table_name = #{quote(name)}
+            AND fk.table_schema = #{scope[:schema]}
+            AND fk.table_name = #{scope[:name]}
+            AND rc.table_name = #{scope[:name]}
         SQL
 
         fk_info.map do |row|
@@ -603,14 +554,14 @@ module ActiveRecord
       def primary_keys(table_name) # :nodoc:
         raise ArgumentError unless table_name.present?
 
-        schema, name = extract_schema_qualified_name(table_name)
+        scope = quoted_scope(table_name)
 
         select_values(<<-SQL.strip_heredoc, "SCHEMA")
           SELECT column_name
           FROM information_schema.key_column_usage
           WHERE constraint_name = 'PRIMARY'
-            AND table_schema = #{quote(schema)}
-            AND table_name = #{quote(name)}
+            AND table_schema = #{scope[:schema]}
+            AND table_name = #{scope[:name]}
           ORDER BY ordinal_position
         SQL
       end
@@ -948,12 +899,6 @@ module ActiveRecord
           )
         end
 
-        def extract_schema_qualified_name(string) # :nodoc:
-          schema, name = string.to_s.scan(/[^`.\s]+|`[^`]*`/)
-          schema, name = @config[:database], schema unless name
-          [schema, name]
-        end
-
         def integer_to_sql(limit) # :nodoc:
           case limit
           when 1; "tinyint"
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
new file mode 100644
index 0000000000..10c8bd179a
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
@@ -0,0 +1,33 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module SchemaStatements # :nodoc:
+        private
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+
+            sql = "SELECT table_name FROM information_schema.tables"
+            sql << " WHERE table_schema = #{scope[:schema]}"
+            sql << " AND table_name = #{scope[:name]}" if scope[:name]
+            sql << " AND table_type = #{scope[:type]}" if scope[:type]
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            schema, name = extract_schema_qualified_name(name)
+            scope = {}
+            scope[:schema] = schema ? quote(schema) : "database()"
+            scope[:name] = quote(name) if name
+            scope[:type] = quote(type) if type
+            scope
+          end
+
+          def extract_schema_qualified_name(string)
+            schema, name = string.to_s.scan(/[^`.\s]+|`[^`]*`/)
+            schema, name = nil, schema unless name
+            [schema, name]
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index a61d920a73..aaa67a9ea2 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -54,81 +54,13 @@ module ActiveRecord
           execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
         end
 
-        # Returns the list of all tables in the schema search path.
-        def tables
-          select_values("SELECT tablename FROM pg_tables WHERE schemaname = ANY(current_schemas(false))", "SCHEMA")
-        end
-
-        def data_sources # :nodoc
-          select_values(<<-SQL, "SCHEMA")
-            SELECT c.relname
-            FROM pg_class c
-            LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
-            WHERE c.relkind IN ('r','v','m') -- (r)elation/table, (v)iew, (m)aterialized view
-            AND n.nspname = ANY (current_schemas(false))
-          SQL
-        end
-
-        def views # :nodoc:
-          select_values(<<-SQL, "SCHEMA")
-            SELECT c.relname
-            FROM pg_class c
-            LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
-            WHERE c.relkind IN ('v','m') -- (v)iew, (m)aterialized view
-            AND n.nspname = ANY (current_schemas(false))
-          SQL
-        end
-
-        # Returns true if table exists.
-        # If the schema is not specified as part of +name+ then it will only find tables within
-        # the current schema search path (regardless of permissions to access tables in other schemas)
-        def table_exists?(name)
-          name = Utils.extract_schema_qualified_name(name.to_s)
-          return false unless name.identifier
-
-          select_values(<<-SQL, "SCHEMA").any?
-            SELECT tablename
-            FROM pg_tables
-            WHERE tablename = #{quote(name.identifier)}
-            AND schemaname = #{name.schema ? quote(name.schema) : "ANY (current_schemas(false))"}
-          SQL
-        end
-
-        def data_source_exists?(name) # :nodoc:
-          name = Utils.extract_schema_qualified_name(name.to_s)
-          return false unless name.identifier
-
-          select_values(<<-SQL, "SCHEMA").any?
-            SELECT c.relname
-            FROM pg_class c
-            LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
-            WHERE c.relkind IN ('r','v','m') -- (r)elation/table, (v)iew, (m)aterialized view
-            AND c.relname = #{quote(name.identifier)}
-            AND n.nspname = #{name.schema ? quote(name.schema) : "ANY (current_schemas(false))"}
-          SQL
-        end
-
-        def view_exists?(view_name) # :nodoc:
-          name = Utils.extract_schema_qualified_name(view_name.to_s)
-          return false unless name.identifier
-
-          select_values(<<-SQL, "SCHEMA").any?
-            SELECT c.relname
-            FROM pg_class c
-            LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
-            WHERE c.relkind IN ('v','m') -- (v)iew, (m)aterialized view
-            AND c.relname = #{quote(name.identifier)}
-            AND n.nspname = #{name.schema ? quote(name.schema) : "ANY (current_schemas(false))"}
-          SQL
-        end
-
         def drop_table(table_name, options = {}) # :nodoc:
           execute "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
         end
 
         # Returns true if schema exists.
         def schema_exists?(name)
-          select_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = '#{name}'", "SCHEMA").to_i > 0
+          select_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = #{quote(name)}", "SCHEMA").to_i > 0
         end
 
         # Verifies existence of an index with a given name.
@@ -138,8 +70,8 @@ module ActiveRecord
               Passing default to #index_name_exists? is deprecated without replacement.
             MSG
           end
-          table = Utils.extract_schema_qualified_name(table_name.to_s)
-          index = Utils.extract_schema_qualified_name(index_name.to_s)
+          table = quoted_scope(table_name)
+          index = quoted_scope(index_name)
 
           select_value(<<-SQL, "SCHEMA").to_i > 0
             SELECT COUNT(*)
@@ -148,9 +80,9 @@ module ActiveRecord
             INNER JOIN pg_class i ON d.indexrelid = i.oid
             LEFT JOIN pg_namespace n ON n.oid = i.relnamespace
             WHERE i.relkind = 'i'
-              AND i.relname = '#{index.identifier}'
-              AND t.relname = '#{table.identifier}'
-              AND n.nspname = #{index.schema ? "'#{index.schema}'" : 'ANY (current_schemas(false))'}
+              AND i.relname = #{index[:name]}
+              AND t.relname = #{table[:name]}
+              AND n.nspname = #{index[:schema]}
           SQL
         end
 
@@ -162,7 +94,7 @@ module ActiveRecord
             MSG
           end
 
-          table = Utils.extract_schema_qualified_name(table_name.to_s)
+          scope = quoted_scope(table_name)
 
           result = query(<<-SQL, "SCHEMA")
             SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
@@ -176,8 +108,8 @@ module ActiveRecord
             LEFT JOIN pg_namespace n ON n.oid = i.relnamespace
             WHERE i.relkind = 'i'
               AND d.indisprimary = 'f'
-              AND t.relname = '#{table.identifier}'
-              AND n.nspname = #{table.schema ? "'#{table.schema}'" : 'ANY (current_schemas(false))'}
+              AND t.relname = #{scope[:name]}
+              AND n.nspname = #{scope[:schema]}
             ORDER BY i.relname
           SQL
 
@@ -239,22 +171,22 @@ module ActiveRecord
 
         # Returns a comment stored in database for given table
         def table_comment(table_name) # :nodoc:
-          name = Utils.extract_schema_qualified_name(table_name.to_s)
-          if name.identifier
+          scope = quoted_scope(table_name, type: "BASE TABLE")
+          if scope[:name]
             select_value(<<-SQL.strip_heredoc, "SCHEMA")
               SELECT pg_catalog.obj_description(c.oid, 'pg_class')
               FROM pg_catalog.pg_class c
                 LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
-              WHERE c.relname = #{quote(name.identifier)}
-                AND c.relkind IN ('r') -- (r)elation/table
-                AND n.nspname = #{name.schema ? quote(name.schema) : 'ANY (current_schemas(false))'}
+              WHERE c.relname = #{scope[:name]}
+                AND c.relkind IN (#{scope[:type]})
+                AND n.nspname = #{scope[:schema]}
             SQL
           end
         end
 
         # Returns the current database name.
         def current_database
-          select_value("select current_database()", "SCHEMA")
+          select_value("SELECT current_database()", "SCHEMA")
         end
 
         # Returns the current schema name.
@@ -430,7 +362,7 @@ module ActiveRecord
         end
 
         def primary_keys(table_name) # :nodoc:
-          name = Utils.extract_schema_qualified_name(table_name.to_s)
+          scope = quoted_scope(table_name)
           select_values(<<-SQL.strip_heredoc, "SCHEMA")
             SELECT column_name
               FROM information_schema.key_column_usage kcu
@@ -439,8 +371,8 @@ module ActiveRecord
                AND kcu.table_schema = tc.table_schema
                AND kcu.constraint_name = tc.constraint_name
              WHERE constraint_type = 'PRIMARY KEY'
-               AND kcu.table_name = #{quote(name.identifier)}
-               AND kcu.table_schema = #{name.schema ? quote(name.schema) : "ANY (current_schemas(false))"}
+               AND kcu.table_name = #{scope[:name]}
+               AND kcu.table_schema = #{scope[:schema]}
              ORDER BY kcu.ordinal_position
           SQL
         end
@@ -579,6 +511,7 @@ module ActiveRecord
         end
 
         def foreign_keys(table_name)
+          scope = quoted_scope(table_name)
           fk_info = select_all(<<-SQL.strip_heredoc, "SCHEMA")
             SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
             FROM pg_constraint c
@@ -588,8 +521,8 @@ module ActiveRecord
             JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
             JOIN pg_namespace t3 ON c.connamespace = t3.oid
             WHERE c.contype = 'f'
-              AND t1.relname = #{quote(table_name)}
-              AND t3.nspname = ANY (current_schemas(false))
+              AND t1.relname = #{scope[:name]}
+              AND t3.nspname = #{scope[:schema]}
             ORDER BY c.conname
           SQL
 
@@ -677,6 +610,39 @@ module ActiveRecord
           )
           PostgreSQLTypeMetadata.new(simple_type, oid: oid, fmod: fmod)
         end
+
+        private
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+            scope[:type] ||= "'r','v','m'" # (r)elation/table, (v)iew, (m)aterialized view
+
+            sql = "SELECT c.relname FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace"
+            sql << " WHERE n.nspname = #{scope[:schema]}"
+            sql << " AND c.relname = #{scope[:name]}" if scope[:name]
+            sql << " AND c.relkind IN (#{scope[:type]})"
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            schema, name = extract_schema_qualified_name(name)
+            type = \
+              case type
+              when "BASE TABLE"
+                "'r'"
+              when "VIEW"
+                "'v','m'"
+              end
+            scope = {}
+            scope[:schema] = schema ? quote(schema) : "ANY (current_schemas(false))"
+            scope[:name] = quote(name) if name
+            scope[:type] = type if type
+            scope
+          end
+
+          def extract_schema_qualified_name(string)
+            name = Utils.extract_schema_qualified_name(string.to_s)
+            [name.schema, name.identifier]
+          end
       end
     end
   end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 36c9815547..b6f595c86c 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -3,6 +3,7 @@ gem "pg", "~> 0.18"
 require "pg"
 
 require "active_record/connection_adapters/abstract_adapter"
+require "active_record/connection_adapters/statement_pool"
 require "active_record/connection_adapters/postgresql/column"
 require "active_record/connection_adapters/postgresql/database_statements"
 require "active_record/connection_adapters/postgresql/explain_pretty_printer"
@@ -15,7 +16,6 @@ require "active_record/connection_adapters/postgresql/schema_dumper"
 require "active_record/connection_adapters/postgresql/schema_statements"
 require "active_record/connection_adapters/postgresql/type_metadata"
 require "active_record/connection_adapters/postgresql/utils"
-require "active_record/connection_adapters/statement_pool"
 
 module ActiveRecord
   module ConnectionHandling # :nodoc:
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
new file mode 100644
index 0000000000..4ba245a0d8
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
@@ -0,0 +1,32 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      module SchemaStatements # :nodoc:
+        private
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+            scope[:type] ||= "'table','view'"
+
+            sql = "SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence'"
+            sql << " AND name = #{scope[:name]}" if scope[:name]
+            sql << " AND type IN (#{scope[:type]})"
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            type = \
+              case type
+              when "BASE TABLE"
+                "'table'"
+              when "VIEW"
+                "'view'"
+              end
+            scope = {}
+            scope[:name] = quote(name) if name
+            scope[:type] = type if type
+            scope
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index 16ef195bfc..1226383cad 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -5,6 +5,7 @@ require "active_record/connection_adapters/sqlite3/quoting"
 require "active_record/connection_adapters/sqlite3/schema_creation"
 require "active_record/connection_adapters/sqlite3/schema_definitions"
 require "active_record/connection_adapters/sqlite3/schema_dumper"
+require "active_record/connection_adapters/sqlite3/schema_statements"
 
 gem "sqlite3", "~> 1.3.6"
 require "sqlite3"
@@ -55,6 +56,7 @@ module ActiveRecord
 
       include SQLite3::Quoting
       include SQLite3::ColumnDumper
+      include SQLite3::SchemaStatements
 
       NATIVE_DATABASE_TYPES = {
         primary_key:  "INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL",
@@ -274,45 +276,6 @@ module ActiveRecord
 
       # SCHEMA STATEMENTS ========================================
 
-      def tables # :nodoc:
-        select_values("SELECT name FROM sqlite_master WHERE type = 'table' AND name <> 'sqlite_sequence'", "SCHEMA")
-      end
-
-      def data_sources # :nodoc:
-        select_values("SELECT name FROM sqlite_master WHERE type IN ('table','view') AND name <> 'sqlite_sequence'", "SCHEMA")
-      end
-
-      def views # :nodoc:
-        select_values("SELECT name FROM sqlite_master WHERE type = 'view' AND name <> 'sqlite_sequence'", "SCHEMA")
-      end
-
-      def table_exists?(table_name) # :nodoc:
-        return false unless table_name.present?
-
-        sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name <> 'sqlite_sequence'"
-        sql << " AND name = #{quote(table_name)}"
-
-        select_values(sql, "SCHEMA").any?
-      end
-
-      def data_source_exists?(table_name) # :nodoc:
-        return false unless table_name.present?
-
-        sql = "SELECT name FROM sqlite_master WHERE type IN ('table','view') AND name <> 'sqlite_sequence'"
-        sql << " AND name = #{quote(table_name)}"
-
-        select_values(sql, "SCHEMA").any?
-      end
-
-      def view_exists?(view_name) # :nodoc:
-        return false unless view_name.present?
-
-        sql = "SELECT name FROM sqlite_master WHERE type = 'view' AND name <> 'sqlite_sequence'"
-        sql << " AND name = #{quote(view_name)}"
-
-        select_values(sql, "SCHEMA").any?
-      end
-
       def new_column_from_field(table_name, field) # :nondoc:
         case field["dflt_value"]
         when /^null$/i
@@ -545,7 +508,7 @@ module ActiveRecord
         end
 
         def sqlite_version
-          @sqlite_version ||= SQLite3Adapter::Version.new(select_value("select sqlite_version(*)"))
+          @sqlite_version ||= SQLite3Adapter::Version.new(select_value("SELECT sqlite_version(*)"))
         end
 
         def translate_exception(exception, message)
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index a6afb7816b..fc5b95f26e 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -276,8 +276,7 @@ module ActiveRecord
 
       def test_tables_logs_name
         sql = <<-SQL
-          SELECT name FROM sqlite_master
-          WHERE type = 'table' AND name <> 'sqlite_sequence'
+          SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence' AND type IN ('table')
         SQL
         assert_logged [[sql.squish, "SCHEMA", []]] do
           @conn.tables
@@ -295,8 +294,7 @@ module ActiveRecord
       def test_table_exists_logs_name
         with_example_table do
           sql = <<-SQL
-            SELECT name FROM sqlite_master
-            WHERE type = 'table' AND name <> 'sqlite_sequence' AND name = 'ex'
+            SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence' AND name = 'ex' AND type IN ('table')
           SQL
           assert_logged [[sql.squish, "SCHEMA", []]] do
             assert @conn.table_exists?("ex")