Database schema definition, discovery and conversion
[](https://crates.io/crates/sea-schema) [](https://docs.rs/sea-schema) [](https://github.com/SeaQL/sea-schema/actions/workflows/rust.yml) Built with ❤️ by 🌊🦀🐚SeaSchema is a library to help you manage database schema. It provides data structures for representing schema definition and query helpers to discover such schema from INFORMATION_SCHEMA.
For now, MySQL support is almost done and Postgres support is in progress. At the end, we'd want to support schema conversion between MySQL and Postgres.
Take the MySQL Sakila Sample Database as example, given the following table:
``SQL
CREATE TABLE film_actor (
actor_id SMALLINT UNSIGNED NOT NULL,
film_id SMALLINT UNSIGNED NOT NULL,
last_update TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (actor_id,film_id),
KEY idx_fk_film_id (filmid`),
CONSTRAINT fkfilmactoractor FOREIGN KEY (actorid) REFERENCES actor (actorid) ON DELETE RESTRICT ON UPDATE CASCADE,
CONSTRAINT fkfilmactorfilm FOREIGN KEY (filmid) REFERENCES film (film_id) ON DELETE RESTRICT ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
```
The discovered schema by querying INFORMATION_SCHEMA results in:
rust
TableDef {
info: TableInfo {
name: "film_actor",
engine: InnoDb,
auto_increment: None,
char_set: Utf8Mb4,
collation: Utf8Mb40900AiCi,
comment: "",
},
columns: [
ColumnInfo {
name: "actor_id",
col_type: SmallInt(
NumericAttr {
maximum: None,
decimal: None,
unsigned: Some(
true,
),
zero_fill: None,
},
),
null: false,
key: Primary,
default: None,
extra: ColumnExtra {
auto_increment: false,
on_update_current_timestamp: false,
generated: false,
default_generated: false,
},
expression: None,
comment: "",
},
ColumnInfo {
name: "film_id",
col_type: SmallInt(
NumericAttr {
maximum: None,
decimal: None,
unsigned: Some(
true,
),
zero_fill: None,
},
),
null: false,
key: Primary,
default: None,
extra: ColumnExtra {
auto_increment: false,
on_update_current_timestamp: false,
generated: false,
default_generated: false,
},
expression: None,
comment: "",
},
ColumnInfo {
name: "last_update",
col_type: Timestamp(
TimeAttr {
fractional: None,
},
),
null: false,
key: NotKey,
default: Some(
ColumnDefault {
expr: "CURRENT_TIMESTAMP",
},
),
extra: ColumnExtra {
auto_increment: false,
on_update_current_timestamp: true,
generated: false,
default_generated: true,
},
expression: None,
comment: "",
},
],
indexes: [
IndexInfo {
unique: false,
name: "idx_fk_film_id",
columns: [
"film_id",
],
order: Ascending,
sub_part: None,
nullable: false,
idx_type: BTree,
comment: "",
functional: false,
},
IndexInfo {
unique: true,
name: "PRIMARY",
columns: [
"actor_id",
"film_id",
],
order: Ascending,
sub_part: None,
nullable: false,
idx_type: BTree,
comment: "",
functional: false,
},
],
foreign_keys: [
ForeignKeyInfo {
name: "fk_film_actor_actor",
columns: [
"actor_id",
],
referenced_table: "actor",
referenced_columns: [
"actor_id",
],
on_update: Cascade,
on_delete: Restrict,
},
ForeignKeyInfo {
name: "fk_film_actor_film",
columns: [
"film_id",
],
referenced_table: "film",
referenced_columns: [
"film_id",
],
on_update: Cascade,
on_delete: Restrict,
},
],
},