Add headers to examples

docs/operations/add_column.mdx

@@ -41,29 +41,41 @@ Default values are subject to the usual rules for quoting SQL expressions. In pa
 
 ## Examples
 
+### Add multiple columns
+
 Add three new columns to the `products` table. Each column addition is a separate operation:
 
 <ExampleSnippet example="03_add_column.json" language="json" />
 
+### Add column with `up` SQL
+
 Add a new column to the `users` table and define `up` SQL to ensure that the new column is populated with a value when a row is added to the old version of the table:
 
 <ExampleSnippet example="06_add_column_to_sql_table.json" language="json" />
 
+### Add column without `up` SQL
+
 Add a new column to the `reviews` table. There is no need for `up` SQL because the column has a default:
 
 <ExampleSnippet example="17_add_rating_column.json" language="json" />
 
+### Add column with `CHECK` constraint
+
 Add a new column to the `people` table with a `CHECK` constraint defined:
 
 <ExampleSnippet
   example="26_add_column_with_check_constraint.json"
   language="json"
 />
 
+### Add column with comment
+
 Add a new column to the `people` table with a comment defined on the new column:
 
 <ExampleSnippet example="30_add_column_simple_up.json" language="json" />
 
+### Add column with a user defined type
+
 Add a new column to the `fruits` table that has an enum type, defined in an earlier migration:
 
 <ExampleSnippet example="41_add_enum_column.json" language="json" />

docs/operations/alter_column/add_check_constraint.mdx

@@ -24,6 +24,8 @@ The `up` SQL expression is used to migrate values from the column in the old sch
 
 ## Examples
 
+### Add a `CHECK` constraint
+
 Add a `CHECK` constraint to the `title` column in the `posts` table. 
 
 The `up` SQL migrates values to ensure they meet the constraint. The `down` SQL copies values without modification from column in the new schema version to the column in the old schema version:

docs/operations/alter_column/add_foreign_key.mdx

@@ -24,6 +24,8 @@ description: Add a foreign key constraint to a column.
 
 ## Examples
 
+### Add a foreign key constraint
+
 Add a `FOREIGN KEY` constraint to the `user_id` column in the `posts` table:
 
 <ExampleSnippet example="21_add_foreign_key_constraint.json" language="json" />

docs/operations/alter_column/add_not_null_constraint.mdx

@@ -21,6 +21,8 @@ Use `up` to migrate values from the nullable column in the old schema view to th
 
 ## Examples
 
+### Add a `NOT NULL` constraint
+
 Add a `NOT NULL` constraint to the `review` column in the `reviews` table.
 
 <ExampleSnippet example="16_set_nullable.json" language="json" />

docs/operations/alter_column/add_unique_constraint.mdx

@@ -23,6 +23,8 @@ Use the `up` SQL expression to migrate values from the old non-unique column in
 
 ## Examples
 
+### Add a `UNIQUE` constraint
+
 Add a `UNIQUE` constraint to the `review` column in the `reviews` table. The `up` SQL appends a random suffix to ensure uniqueness:
 
 <ExampleSnippet example="15_set_column_unique.json" language="json" />

docs/operations/alter_column/change_comment.mdx

@@ -21,10 +21,14 @@ The comment is added directly to the column on migration start.
 
 ## Examples
 
+### Alter many column properties
+
 An alter column migration performs many operations, including setting a comment: 
 
 <ExampleSnippet example="35_alter_column_multiple.json" language="json" />
 
+### Remove a comment
+
 To remove a comment from a column set `comment` to `NULL`:
 
 <ExampleSnippet example="36_set_comment_to_null.json" language="json" />

docs/operations/alter_column/change_default.mdx

@@ -23,10 +23,14 @@ To remove a column default, set the `default` field to `NULL`.
 
 ## Examples
 
+### Make multiple column changes
+
 An alter column migration that makes multiple changes including setting the default:
 
 <ExampleSnippet example="35_alter_column_multiple.json" language="json" />
 
+### Drop a column default
+
 Drop a default by setting the `default` field to `null`.
 
 <ExampleSnippet example="46_alter_column_drop_default.json" language="json" />

docs/operations/alter_column/change_type.mdx

@@ -23,6 +23,8 @@ Use the `down` SQL expression to do data conversion in the other direction; from
 
 ## Examples
 
+### Change column type
+
 Change the type of the `rating` column on the `reviews` table:
 
 <ExampleSnippet example="18_change_column_type.json" language="json" />

docs/operations/alter_column/drop_not_null_constraint.mdx

@@ -19,6 +19,8 @@ description: Drop not null operations drop a `NOT NULL` constraint from a column
 
 ## Examples
 
+### Remove `NOT NULL` from a column
+
 Remove `NOT NULL` from the `title` column in the `posts` table:
 
 <ExampleSnippet example="31_unset_not_null.json" language="json" />

docs/operations/alter_column/rename_column.mdx

@@ -19,6 +19,8 @@ In the new schema version, the column will have its new name. In the old schema
 
 ## Examples
 
+### Rename a column
+
 Rename the `role` column in the `employees` table:
 
 <ExampleSnippet example="13_rename_column.json" language="json" />

docs/operations/create_constraint.mdx

@@ -52,14 +52,20 @@ An `up` and `down` SQL expression is required for each column covered by the con
 
 ## Examples
 
+### Add a `UNIQUE` constraint
+
 Add a multi-column unique constraint on the `tickets` table:
 
 <ExampleSnippet example="44_add_table_unique_constraint.json" language="json" />
 
+### Add a `CHECK` constraint
+
 Add a check constraint on the `sellers_name` and `sellers_zip` fields on the `ticket` table. The `up` SQL expression ensures that pairs of values not meeting the new constraint on the old columns are data migrated to values that meet the new constraint in the new columns:
 
 <ExampleSnippet example="45_add_table_check_constraint.json" language="json" />
 
+### Add a `FOREIGN KEY` constraint
+
 Add a multi-column foreign key constraint to the the `tickets` table. The `up` SQL expressions here don't do any data transformation:
 
 <ExampleSnippet

docs/operations/create_index.mdx

@@ -24,21 +24,29 @@ description: A create index operation creates a new index on a set of columns.
 
 ## Examples
 
+### Create a `btree` index
+
 Create a `btree` index on the `name` column in the `fruits` table:
 
 <ExampleSnippet example="10_create_index.json" language="json" />
 
+### Create a partial index
+
 Create a partial index on the `id` column in the `fruits` table:
 
 <ExampleSnippet example="37_create_partial_index.json" language="json" />
 
+### Create an index with storage parameters
+
 Set storage parameters and index method:
 
 <ExampleSnippet
   example="38_create_hash_index_with_fillfactor.json"
   language="json"
 />
 
+### Create a unique index
+
 Create a unique index:
 
 <ExampleSnippet example="42_create_unique_index.json" language="json" />

docs/operations/create_table.mdx

@@ -42,33 +42,49 @@ Default values are subject to the usual rules for quoting SQL expressions. In pa
 
 ## Examples
 
+### Create multiple tables
+
 Create multiple tables. Each table is a separate operation in the migration:
 
 <ExampleSnippet example="01_create_tables.json" language="json" />
 
+### Create one table
+
 Create one table:
 
 <ExampleSnippet example="02_create_another_table.json" language="json" />
 
+### Create one table (2)
+
 Create one table:
 
 <ExampleSnippet example="08_create_fruits_table.json" language="json" />
 
+### Create one table (3)
+
+Create one table:
+
+<ExampleSnippet example="20_create_posts_table.json" language="json" />
+
+### Create a table with a comment 
+
 Create a table with a comment on the table:
 
 <ExampleSnippet example="12_create_employees_table.json" language="json" />
 
+### Create a table with nullable and non-nullable columns
+
 Create a table with a mix of nullable and non-nullable columns:
 
 <ExampleSnippet example="14_add_reviews_table.json" language="json" />
 
+### Create a table with a foreign key
+
 Create a table with a foreign key constraint defined on a column:
 
 <ExampleSnippet example="19_create_orders_table.json" language="json" />
 
-Create a table:
-
-<ExampleSnippet example="20_create_posts_table.json" language="json" />
+### Create a table with a `CHECK` constraint
 
 Create a table with a `CHECK` constraint on one column:
 
@@ -77,6 +93,8 @@ Create a table with a `CHECK` constraint on one column:
   language="json"
 />
 
+### Create a table with column defaults
+
 Create a table with different `DEFAULT` values:
 
 <ExampleSnippet example="28_different_defaults.json" language="json" />

docs/operations/drop_column.mdx

@@ -19,6 +19,8 @@ The `down` field above is required in order to backfill the previous version of
 
 ## Examples
 
-Drop a column with a default value - if a new row is inserted against the new schema without a `price` column, the old schema `price` column will be set to `0`.
+### Drop a column
+
+Drop a column - if a new row is inserted against the new schema without a `price` column, the old schema `price` column will be set to `0`.
 
 <ExampleSnippet example="09_drop_column.json" language="json" />

docs/operations/drop_constraint.mdx

@@ -26,14 +26,20 @@ Only `CHECK`, `FOREIGN KEY`, and `UNIQUE` constraints can be dropped.
 
 ## Examples
 
+### Drop a `CHECK` constraint:
+
 Drop a `CHECK` constraint:
 
 <ExampleSnippet example="23_drop_check_constraint.json" language="json" />
 
+### Drop a `FOREIGN KEY` constraint:
+
 Drop a `FOREIGN KEY` constraint:
 
 <ExampleSnippet example="24_drop_foreign_key_constraint.json" language="json" />
 
+### Drop a `UNIQUE` constraint:
+
 Drop a `UNIQUE` constraint:
 
 <ExampleSnippet example="27_drop_unique_constraint.json" language="json" />

docs/operations/drop_index.mdx

@@ -15,6 +15,8 @@ description: A drop index operation drops an index from a table.
 
 ## Examples
 
+### Drop an index
+
 Drop an index defined on the `fruits` table:
 
 <ExampleSnippet example="11_drop_index.json" language="json" />

docs/operations/drop_multi_column_constraint.mdx

@@ -45,6 +45,8 @@ The new versions of the columns will no longer have the constraint, but in the o
 
 ## Examples
 
+### Drop a `CHECK` constraint
+
 Drop a `CHECK` constraint defined on the `tickets` table.
 
 <ExampleSnippet example="48_drop_tickets_check.json" language="json" />

docs/operations/drop_table.mdx

@@ -17,6 +17,8 @@ The table is not visible in the new version of the schema created when the migra
 
 ## Examples
 
+### Drop a table
+
 Drop the products table:
 
 <ExampleSnippet example="07_drop_table.json" language="json" />

docs/operations/raw_sql.mdx

@@ -38,10 +38,14 @@ The `onComplete` flag will make this operation run the `up` expression on the co
 
 ## Examples
 
+### Create a table with a raw SQL migration
+
 A raw SQL migration to create a table:
 
 <ExampleSnippet example="05_sql.json" language="json" />
 
+### Run a SQL migration on migration complete
+
 A raw SQL migration run on migration completion rather than start.
 
 <ExampleSnippet example="32_sql_on_complete.json" language="json" />

docs/operations/rename_constraint.mdx

@@ -19,6 +19,8 @@ The constraint is renamed on migration completion; it retains its old name durin
 
 ## Examples
 
+### Rename a `CHECK` constraint
+
 Rename a `CHECK` constraint:
 
 <ExampleSnippet example="33_rename_check_constraint.json" language="json" />

docs/operations/rename_table.mdx

@@ -20,6 +20,8 @@ The table itself is renamed on migration completion.
 
 ## Examples
 
+### Rename a table
+
 Rename the customers table:
 
 <ExampleSnippet example="04_rename_table.json" language="json" />

docs/operations/set_replica_identity.mdx

@@ -31,4 +31,6 @@ description: A set replica identity operation sets the replica identity for a ta
 
 ## Examples
 
+### Set replica identity
+
 <ExampleSnippet example="29_set_replica_identity.json" language="json" />