zeus
85 lines
3.2 KiB
Swift
85 lines
3.2 KiB
Swift
struct SQLTableAlterationGenerator {
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private enum TableAlterationKind {
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case addColumn(SQLColumnGenerator)
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case addIndex(SQLIndexGenerator)
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case renameColumn(old: String, new: String)
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case dropColumn(String)
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}
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private var name: String
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private var alterations: [TableAlterationKind] = []
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func sql(_ db: Database) throws -> String {
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var statements: [String] = []
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for alteration in alterations {
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switch alteration {
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case let .addColumn(column):
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var chunks: [String] = []
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chunks.append("ALTER TABLE")
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chunks.append(name.quotedDatabaseIdentifier)
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chunks.append("ADD COLUMN")
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let sql = try column.sql(db, tableName: name, primaryKeyColumns: {
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try db.primaryKey(name).columnInfos.map { columnInfos in
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columnInfos.map { SQLColumnDescriptor($0) }
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}
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})
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chunks.append(sql)
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let statement = chunks.joined(separator: " ")
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statements.append(statement)
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case let .addIndex(index):
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try statements.append(index.sql(db))
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case let .renameColumn(oldName, newName):
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var chunks: [String] = []
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chunks.append("ALTER TABLE")
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chunks.append(name.quotedDatabaseIdentifier)
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chunks.append("RENAME COLUMN")
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chunks.append(oldName.quotedDatabaseIdentifier)
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chunks.append("TO")
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chunks.append(newName.quotedDatabaseIdentifier)
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let statement = chunks.joined(separator: " ")
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statements.append(statement)
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case let .dropColumn(column):
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var chunks: [String] = []
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chunks.append("ALTER TABLE")
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chunks.append(name.quotedDatabaseIdentifier)
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chunks.append("DROP COLUMN")
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chunks.append(column.quotedDatabaseIdentifier)
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let statement = chunks.joined(separator: " ")
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statements.append(statement)
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}
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}
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return statements.joined(separator: "; ")
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}
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}
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extension SQLTableAlterationGenerator {
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init(_ tableAlteration: TableAlteration) {
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self.name = tableAlteration.name
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self.alterations = []
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for alteration in tableAlteration.alterations {
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switch alteration {
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case let .add(column):
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alterations.append(.addColumn(.columnDefinition(column)))
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if let indexDefinition = column.indexDefinition(in: name) {
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alterations.append(.addIndex(SQLIndexGenerator(index: indexDefinition)))
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}
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case let .addColumnLiteral(sql):
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alterations.append(.addColumn(.columnLiteral(sql)))
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case let .rename(old: oldName, new: newName):
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alterations.append(.renameColumn(old: oldName, new: newName))
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case let .drop(column):
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alterations.append(.dropColumn(column))
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}
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}
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}
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}
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