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//! `MigrationEngine` SQL generation — Up/Down DDL from `SchemaChange` lists.
use super::dialect::MigrationDialect;
use super::diff::index_name;
use super::engine::MigrationEngine;
use super::history::{MIGRATION_HISTORY_TABLE, PRODUCT_VERSION};
use super::schema_change::SchemaChange;
use super::types::{ModelSnapshot, SnapshotColumn};
impl MigrationEngine {
pub(crate) fn initial_create_with_fks(&self, current: &ModelSnapshot) -> Vec<SchemaChange> {
let mut changes = self.initial_create(current);
for et in ¤t.entity_types {
Self::append_create_table_fks(&mut changes, &et.table_name, &et.columns);
Self::append_create_table_indexes(&mut changes, &et.table_name, &et.columns);
}
changes
}
// -----------------------------------------------------------------------
// SQL generation
// -----------------------------------------------------------------------
/// Standard foreign-key constraint name used by Add/DropForeignKey.
pub fn foreign_key_name(table: &str, column: &str, referenced_table: &str) -> String {
format!("fk_{}_{}_{}", table, column, referenced_table)
}
/// Standard index name used by CreateIndex/DropIndex.
pub fn index_name(table: &str, column: &str) -> String {
format!("ix_{}_{}", table, column)
}
pub fn generate_alter_column_sql(
&self,
table: &str,
column_name: &str,
new: &SnapshotColumn,
) -> String {
let q = |s: &str| self.dialect.quote(s);
let col_type = self.dialect.map_column_type(new);
match self.dialect {
MigrationDialect::Postgres => {
let nullable = if new.is_required {
"SET NOT NULL"
} else {
"DROP NOT NULL"
};
format!(
"ALTER TABLE {} ALTER COLUMN {} TYPE {};\nALTER TABLE {} ALTER COLUMN {} {};\n",
q(table),
q(column_name),
col_type,
q(table),
q(column_name),
nullable
)
}
MigrationDialect::MySql => {
let nullable = if new.is_required { "NOT NULL" } else { "NULL" };
format!(
"ALTER TABLE {} MODIFY COLUMN {} {} {};\n",
q(table),
q(column_name),
col_type,
nullable
)
}
MigrationDialect::Sqlite => format!(
"-- SQLite does not support ALTER COLUMN type changes; \
rebuild table manually for {}.{}\n",
q(table),
q(column_name)
),
}
}
pub(crate) fn generate_up_sql(&self, changes: &[SchemaChange]) -> String {
self.generate_up_sql_inner(changes, true)
}
pub(crate) fn generate_ddl_sql(&self, changes: &[SchemaChange]) -> String {
self.generate_up_sql_inner(changes, false)
}
fn generate_up_sql_inner(&self, changes: &[SchemaChange], record_history: bool) -> String {
let mut sql = String::from("-- Up Migration (auto-generated by rust-ef)\n\n");
let q = |s: &str| self.dialect.quote(s);
let create_kw = if record_history {
"CREATE TABLE"
} else {
"CREATE TABLE IF NOT EXISTS"
};
for change in changes {
match change {
SchemaChange::CreateTable { table, columns } => {
// PostgreSQL: create sequences before the table
if self.dialect == MigrationDialect::Postgres {
for c in columns {
if c.is_sequence {
if let Some(seq_name) = &c.sequence_name {
sql.push_str(&format!(
"CREATE SEQUENCE IF NOT EXISTS {};\n",
q(seq_name)
));
}
}
}
}
sql.push_str(&format!("{} {} (\n", create_kw, q(table)));
// Separate primary key columns from regular columns
let pk_columns: Vec<&str> = columns
.iter()
.filter(|c| c.is_primary_key)
.map(|c| c.column_name.as_str())
.collect();
let col_defs: Vec<String> = columns
.iter()
.map(|c| {
let nullable = if c.is_required { "NOT NULL" } else { "NULL" };
let col_type = self.dialect.map_column_type(c);
// PostgreSQL sequence column: add DEFAULT nextval('seq_name')
if c.is_sequence && self.dialect == MigrationDialect::Postgres {
if let Some(seq_name) = &c.sequence_name {
return format!(
"{} {} DEFAULT nextval('{}') {}",
q(&c.column_name),
col_type,
seq_name,
nullable
);
}
}
// Don't put PRIMARY KEY on individual columns; handle separately
[q(&c.column_name), col_type, nullable.to_string()]
.into_iter()
.filter(|s| !s.is_empty())
.collect::<Vec<_>>()
.join(" ")
})
.collect();
sql.push_str(&format!(" {}\n", col_defs.join(",\n ")));
// Composite primary key constraint
if pk_columns.len() == 1 {
sql.push_str(&format!(" ,PRIMARY KEY ({})\n", q(pk_columns[0])));
} else if pk_columns.len() > 1 {
let pk_list: Vec<String> = pk_columns.iter().map(|c| q(c)).collect();
sql.push_str(&format!(" ,PRIMARY KEY ({})\n", pk_list.join(", ")));
}
sql.push_str(");\n\n");
}
SchemaChange::DropTable { table } => {
sql.push_str(&format!("DROP TABLE IF EXISTS {};\n", q(table)));
}
SchemaChange::AddColumn { table, column } => {
let col_type = self.dialect.map_column_type(column);
let nullable = if column.is_required {
"NOT NULL"
} else {
"NULL"
};
sql.push_str(&format!(
"ALTER TABLE {} ADD COLUMN {} {} {};\n",
q(table),
q(&column.column_name),
col_type,
nullable
));
}
SchemaChange::DropColumn { table, column_name } => {
sql.push_str(&format!(
"ALTER TABLE {} DROP COLUMN IF EXISTS {};\n",
q(table),
q(column_name)
));
}
SchemaChange::AlterColumn {
table,
column_name,
old: _,
new,
} => {
sql.push_str(&self.generate_alter_column_sql(table, column_name, new));
}
SchemaChange::AddForeignKey {
table,
column,
referenced_table,
referenced_column,
on_delete,
} => {
let fk_name = Self::foreign_key_name(table, column, referenced_table);
let on_delete_clause = on_delete
.as_deref()
.map(|c| format!(" ON DELETE {}", c))
.unwrap_or_default();
sql.push_str(&format!(
"ALTER TABLE {} ADD CONSTRAINT {} FOREIGN KEY ({}) REFERENCES {} ({}){};\n",
q(table),
q(&fk_name),
q(column),
q(referenced_table),
q(referenced_column),
on_delete_clause
));
}
SchemaChange::DropForeignKey {
table,
column,
referenced_table,
} => {
let fk_name = Self::foreign_key_name(table, column, referenced_table);
match self.dialect {
MigrationDialect::MySql => sql.push_str(&format!(
"ALTER TABLE {} DROP FOREIGN KEY {};\n",
q(table),
q(&fk_name)
)),
_ => sql.push_str(&format!(
"ALTER TABLE {} DROP CONSTRAINT IF EXISTS {};\n",
q(table),
q(&fk_name)
)),
}
}
SchemaChange::CreateIndex {
table,
column,
is_unique,
} => {
let unique_kw = if *is_unique { "UNIQUE " } else { "" };
let idx_name = index_name(table, column);
sql.push_str(&format!(
"CREATE {unique_kw}INDEX {} ON {} ({});\n",
q(&idx_name),
q(table),
q(column)
));
}
SchemaChange::DropIndex {
table,
column,
is_unique: _,
} => {
let idx_name = index_name(table, column);
match self.dialect {
MigrationDialect::MySql => {
sql.push_str(&format!("DROP INDEX {} ON {};\n", q(&idx_name), q(table)))
}
_ => sql.push_str(&format!("DROP INDEX IF EXISTS {};\n", q(&idx_name))),
}
}
}
}
if record_history {
sql.push_str(&format!(
"INSERT INTO {}(migration_id, product_version) VALUES ('{{migration_id}}', '{}');\n",
q(MIGRATION_HISTORY_TABLE),
PRODUCT_VERSION
));
}
sql
}
pub(super) fn generate_down_sql(&self, changes: &[SchemaChange]) -> String {
let mut sql = String::from("-- Down Migration (auto-generated by rust-ef)\n\n");
let q = |s: &str| self.dialect.quote(s);
// Reverse the changes for the down migration
for change in changes.iter().rev() {
match change {
SchemaChange::CreateTable { table, .. } => {
sql.push_str(&format!("DROP TABLE IF EXISTS {};\n", q(table)));
}
SchemaChange::DropTable { table } => {
sql.push_str(&format!(
"-- WARNING: Cannot restore table {} (original schema unknown)\n",
q(table)
));
}
SchemaChange::AddColumn { table, column } => {
sql.push_str(&format!(
"ALTER TABLE {} DROP COLUMN IF EXISTS {};\n",
q(table),
q(&column.column_name)
));
}
SchemaChange::DropColumn { table, column_name } => {
sql.push_str(&format!(
"-- WARNING: Cannot restore column {} on {} (original type unknown)\n",
q(column_name),
q(table)
));
}
SchemaChange::AlterColumn {
table,
column_name,
old,
new: _,
} => {
sql.push_str(&self.generate_alter_column_sql(table, column_name, old));
}
SchemaChange::AddForeignKey {
table,
column,
referenced_table,
..
} => {
let fk_name = Self::foreign_key_name(table, column, referenced_table);
match self.dialect {
MigrationDialect::MySql => sql.push_str(&format!(
"ALTER TABLE {} DROP FOREIGN KEY {};\n",
q(table),
q(&fk_name)
)),
_ => sql.push_str(&format!(
"ALTER TABLE {} DROP CONSTRAINT IF EXISTS {};\n",
q(table),
q(&fk_name)
)),
}
}
SchemaChange::DropForeignKey {
table,
column,
referenced_table,
..
} => {
sql.push_str(&format!(
"-- WARNING: Cannot restore foreign key constraint {} on {}.{}\n",
q(&Self::foreign_key_name(table, column, referenced_table)),
q(table),
q(column)
));
}
SchemaChange::CreateIndex {
table,
column,
is_unique: _,
} => {
let idx_name = index_name(table, column);
match self.dialect {
MigrationDialect::MySql => {
sql.push_str(&format!("DROP INDEX {} ON {};\n", q(&idx_name), q(table)))
}
_ => sql.push_str(&format!("DROP INDEX IF EXISTS {};\n", q(&idx_name))),
}
}
SchemaChange::DropIndex {
table,
column,
is_unique,
} => {
let unique_kw = if *is_unique { "UNIQUE " } else { "" };
let idx_name = index_name(table, column);
sql.push_str(&format!(
"CREATE {unique_kw}INDEX {} ON {} ({});\n",
q(&idx_name),
q(table),
q(column)
));
}
}
}
sql.push_str(&format!(
"DELETE FROM {} WHERE migration_id = '{{migration_id}}';\n",
q(MIGRATION_HISTORY_TABLE)
));
sql
}
}